Great and blue tits as indicators of heavy metal contamination in terrestrial ecosystems

The first ecological contamination study of avian mercury and lead in southeast Iran, Hamun International Wetlands

The concentrations of mercury (Hg) and lead (Pb) in feather samples of nine bird's species (n = 65) were determined from southeastern areas of Iran, Hamun International Wetlands. Hg concentrations were ranged from 0.40 to 3.00 mg/kg dry wt and from 0.38 to 1.76 mg/kg for primary and secondary feathers, respectively. Furthermore, Pb concentrations were ranged from 1.43 to 4.10 mg/kg and from 1.28 to 3.65 mg/kg for primary and secondary feathers, respectively. Deposition of metals varied significantly among the primary and secondary feathers of systematic category (families) for Hg and Pb (p < 0.001). It was found that there is a significant difference in feather Hg and Pb concentrations across species (p < 0.001) with highest concentrations in saker falcon (Falconidae) (Hg = 3.00 mg/kg and Pb = 4.10 mg/kg, primary feather) followed by little owl (Strigidae). Grey francolin (Phasianidae) contained the least amount of Hg (0.40 mg/kg) and Pb (1.43 mg/kg) in primary feather. The results showed that the highest concentrations of heavy metals were related to carnivores. Fish predators, omnivores, and insectivores were examined at the next level of metal concentration, with herbivores having the lowest concentrations of lead (1.43 mg/kg) and mercury (0.40 mg/kg). Birds with an open grasslands feeding strategy had the highest mercury and lead concentration. The average value for Pb was on the border of harmful effects (4 mg/kg). The results of this study indicate that mercury levels are lower than the threshold level for reproductive and behavioral harm (5 mg/kg).

The Effects of Natural Sounds and Proxemic Distances on the Perception of a Noisy Domestic Flying Robot

When flying robots are used in close-range interaction with humans, the noise they generate, also called consequential sound, is a critical parameter for user acceptance. We conjecture that there is a benefit in adding natural sounds to noisy domestic drones. To test our hypothesis experimentally, we carried out a mixed-methods research study (N=56) on reported user perception of a sonified domestic flying robot with three sound conditions at three distances. The natural sounds studied were respectively added to the robot’s inherent noises during flying; namely a bird song and a rain sound, plus a control condition of no added sound. The distances studied were set according to proxemics; namely near , middle , and far . Our results show that adding bird song or rain sound affects the participants’ perceptions, and the proxemic distances play a nonnegligible role. For instance, we found that participants liked the bird condition the most when the drone was at far , while they disliked the same sound the most when at near . We also found that participants’ perceptions strongly depended on their associations and interpretations deriving from previous experience. We derived six concrete design recommendations.

Multiple trace elements exposure of Grey-cheeked Fulvettas Alcippe morrisonia, a nuclear member in bird mixed-species flocks, and implications for bioindicator

Birds are vulnerable to metal pollution, which can serve as indicators of environmental safety monitoring. In this study, we evaluated three non-essential (Pb, Cd, and As) and two essential (Cu and Zn) trace elements of living (only feathers) and deceased (feathers and tissues) Grey-cheeked Fulvetta (Alcippe morrisonia) at a highly polluted mine tailings and a reference site. Five metal concentrations in the feathers of living Grey-cheeked Fulvettas were higher at the mine site. Among these, the levels of Cd and Pb in most feathers exceeded the threshold, resulting in an ecotoxicological concern. The correlation analysis suggested that feathers from Grey-cheeked Fulvettas might be useful bioindicators for local metal contamination assessment. The toxicological effects of trace metals on Grey-cheeked Fulvetta might affect its leadership ability. Therefore, understanding the effects of metal pollution on Grey-cheeked Fulvetta would show important practical implications for the conservation of bird communities.

Replicated, urban-driven exposure to metallic trace elements in two passerines

While there are increasing examples of phenotypic and genotypic differences between urban and non-urban populations of plants and animals, few studies identified the mechanisms explaining those dissimilarities. The characterization of the urban landscape, which can only be achieved by measuring variability in relevant environmental factors within and between cities, is a keystone prerequisite to understand the effects of urbanization on wildlife. Here, we measured variation in bird exposure to metal pollution within 8 replicated urbanization gradients and within 2 flagship bird species in urban evolutionary ecology: the blue tit (Cyanistes caeruleus) and the great tit (Parus major). We report on a highly significant, positive linear relationship between the magnitude of urbanization-inferred as either tree cover, impervious surface cover, or an urbanization score computed from several environmental variables, and copper, zinc and lead concentrations in bird feathers. The reverse relationship was measured in the case of mercury, while cadmium and arsenic did not vary in response to the urbanization level. This result, replicated across multiple cities and two passerine species, strongly suggests that copper, zinc, lead and mercury pollution is likely to trigger the emergence of parallel responses at the phenotypic and/or genotypic level between urban environments worldwide.

Are Feathers of a Songbird Model Species (The Great Tit, Parus major) Suitable for Monitoring Perfluoroalkyl Acids (PFAAs) in Blood Plasma?

Feathers have been shown to be useful in the biomonitoring of environmental contaminants, such as metals and persistent organic pollutants. However, little is known regarding the levels of perfluoroalkyl acids (PFAAs) in feathers and the applicability of these structures for the biomonitoring of these compounds. In the present study, we report the extent to which feathers are suitable for monitoring PFAA concentrations in the blood plasma of an insectivorous songbird model species, the great tit (Parus major), settled at and in the vicinity of a fluorochemical plant in Antwerp, Belgium. For most of the target analytes (out of the 15 investigated), the feather PFAA concentrations near the plant are the highest ever reported in free-living birds. As PFAA concentrations did not differ in the adjacent sites, no pollution gradient with distance from the plant was observed. In addition, the PFAA concentrations were not associated with the age and sex of the birds. Perfluorooctanoic acid (PFOA) concentrations were significantly higher in P. major feathers than in blood plasma, but for most other PFAAs, these differences were not observed. The concentrations of perfluorooctanesulfonate (PFOS) and PFOA in P. major feathers and plasma were significantly and positively correlated when combining data from all sites but often not at individual sites. This result was likely caused by lower sample sizes at the individual sites and the use of matrices that represent different time periods. Our results suggest that P. major feathers cannot be used to estimate PFOA and PFOS concentrations in blood plasma, except when there is a great deal of variation in pollutant concentrations among sites/individual birds. Both matrices represent different time frames, providing complementary information on environmental PFAA concentrations, as illustrated by the observation that more PFAA compounds could be detected in P. major feathers than in blood plasma.

Longitudinally monitored lifetime changes in blood heavy metal concentrations and their health effects in urban birds

Urban heavy metal pollution can impair the health of humans and other organisms inhabiting cities. While birds are suggested as one of the appropriate bioindicators for essential and non-essential trace element monitoring, the process of particular elements' accumulation in blood and its possible adverse health effects during ageing of individuals remain unexplored. We have investigated lifetime changes in blood lead (Pb), cadmium (Cd), arsenic (As) and zinc (Zn) concentrations and searched for links to health-related traits in sub-urban free-living great tit (Parus major) population monitored over a long period of time. The blood As concentrations were under the limit of detection in most samples. The blood Pb levels showed a non-linear relationship to individuals age, where the highest Pb concentrations were measured in nestlings and in a very small group of highly senescent birds (over 7 years old), while no clear trend was observed for the majority of the adult age stages. No age-related patterns were found for blood Cd or Zn concentrations. The positive relationship between date of capture and blood Cd and Zn levels may reflect seasonal changes in diet composition. We did not reveal any anaemia-like conditions (decreased total erythrocyte count or increased immature erythrocyte count) in relation to blood heavy metal concentrations in the investigated birds. Total leukocyte counts, heterophil/lymphocyte (H/L) ratio and total heterophil and lymphocyte counts increased with increasing Pb, Cd and Zn concentrations in blood. This study demonstrates the suitability of avian blood for actual heavy metal spatial and temporal biomonitoring even in situations when the precise age of the individuals remains unknown.

Sentinel species for biomonitoring and biosurveillance of environmental heavy metals in Nigeria

Nigeria receives copious annual precipitation to nourish its forests and agriculture, it has an extensive river drainage system, and it possesses valuable mineral deposits that stimulate both commercial and artisan mining activities. The combination of these features complicates Nigeria's efforts to produce adequate amounts of healthy foods to support its population. Toxic heavy metals like lead, cadmium, and mercury, and toxic metalloids such as arsenic, are also present in its mineral deposits and they migrate gradually into the soil and water of Nigeria by natural means. However, mining activities can liberate higher levels of toxic metals, which adversely affect Nigerian ecosystems and its food chains. Thus, environmental pollution due to anthropogenic activities is a major public health concern in Nigeria. This review covers the importance of native Nigerian and African wild and cultivated plants along with livestock and wild animals as sentinel species to evaluate heavy metals as environmental stressors and the use of sentinel species for food safety monitoring and for predicting potential risks to human health.

Non-invasive biomonitoring of mercury in birds near thermal power plants: lessons from Maharashtra, India

Thermal power plants (TPPs) have emerged as a major source of air, water, and soil pollution because of the presence of many toxic metals. The presence of mercury (Hg) in fly ash has proven to be toxic in nature because of its tendency to get bioaccumulated and biomagnified in the food chain. The aim of the present study was to understand the presence of toxic Hg in the feathers of wetland birds undertaking the study around a TPP located in Nagpur, India. Local wetland birds especially cattle egrets, heron, and Moorhen were commonly observed dwelling close to fly ash ponds for various purposes (roosting, breeding, feeding, etc.). Samples of fly ash, soil, water, plants, and bird feather were collected, cleaned, and processed for Hg analysis. A mercury analyzer was used to assess the concentration of toxic levels of Hg in samples. Our results reflect leaching of Hg in soil and uptake by plant samples, whereas in water, ash, and bird feather samples concentrations of Hg were fairly below the prescribed limits (World Health Organization). A non-invasive method for understanding the mercury concentration in wetland birds has been established as a potential important monitoring tool to track the fate of toxic metal Hg in the food chain. In summary, our results indicate fairly low Hg levels in feather samples projecting non-invasive biomonitoring as a promising strategy. The study also suggests that a comprehensive monitoring action plan in place for Hg and other toxic metals in the food chain that comes from TPP will be efficient to avoid any pitfalls. Graphical abstract.

Proximity to roads, but not exposure to metal pollution, is associated with accelerated developmental telomere shortening in nestling great tits

Comprehensively understanding the factors affecting physiology and fitness in urban wildlife requires concurrently considering multiple stressors. To this end, we simultaneously assessed how metal pollution and proximity to roads affect body condition and telomere shortening between days 8 and 15 of age in nestling great tits (Parus major), a common urban bird. We employed a repeated-measures sampling design to compare telomere shortening and body condition between nestlings from four urban study sites south of Antwerp, Belgium, which are located at different distances from a metal pollution point source. In addition, we explored associations between metal exposure and telomere dynamics on the individual level by measuring blood concentrations of five metals/metalloids, of which lead, copper and zinc were present at concentrations above the limit of detection. To assess whether roadway-associated stressors (e.g. noise and air pollution) might affect nestling condition and telomere shortening, we measured the proximity of nest boxes to roads. Metal exposure was not associated with nestling telomere length or body condition, despite elevated blood lead concentrations close to the metal pollution source (mean ± SE = 0.270 ± 0.095 μg/g wet weight at the most polluted study site), suggesting that nestlings may have some capacity to detoxify metals. However, nestlings from nest boxes near roads exhibited more telomere shortening between days 8 and 15 of age, and shorter telomeres at day 15. Nestlings in poorer condition also had shorter telomeres, but proximity to the road was unrelated to body condition. Thus, nutritional stress is unlikely to mediate the relationship between proximity to roads and telomere length. Rather, proximity to roads could have affected telomere shortening by exposing nestlings to air or noise pollution. Our study highlights that traffic-related pollution, which is implicated in human health problems, might also affect urban wildlife.

Carotenoid- but not melanin-based plumage coloration is negatively related to metal exposure and proximity to the road in an urban songbird

Rapid urbanization is a global phenomenon that is increasingly exposing organisms to novel stressors. These novel stressors can affect diverse aspects of organismal function, including development of condition-dependent ornaments, which play critical roles in social and sexual selection. We investigated the relationship between metal pollution, proximity to roads, and carotenoid- and melanin-based plumage coloration in a common songbird, the great tit (Parus major). We studied populations located across a well-characterized metal pollution gradient and surrounded by roadway networks. Metal exposure and road-associated pollution could reduce carotenoid-based pigmentation by inducing oxidative stress or affecting habitat quality, but metals could also enhance melanin-based pigmentation, through effects on melanogenesis and testosterone concentrations. Using a large sample size (N > 500), we found that birds residing close to a point source for metals had reduced ultraviolet chroma, a component of carotenoid-based pigmentation. Moreover, birds with high feather metal concentrations had lower carotenoid chroma, hue, and ultraviolet chroma, with effects modified by age class. Birds residing closer to roads also had lower carotenoid chroma and hue. Melanin-based pigmentation showed high between-year repeatability, and no association with anthropogenic pollution. Results suggest that carotenoid-, but not melanin-, based pigmentation is negatively affected by multiple anthropogenic stressors. We are the first to demonstrate a negative association between roads and a plumage-based signaling trait, which could have important implications for sexual signaling dynamics in urban landscapes.

Trace elements exposure of endangered crested ibis (Nipponia nippon) under in situ and ex situ conservations

Crested ibis (Nipponia nippon), one of the rarest birds in the world, was almost extinct in the historically widespread areas partly due to the environmental pollution. Therefore, non-invasive indicators of feather, eggshell, and excrement were used to investigate the exposure of this endangered bird to eleven trace elements in this study. The results indicated that crested ibises under in situ and ex situ conservations were diversely exposed to trace elements, with higher exposure levels of As, Cd, and Mn in the wild, but higher exposure levels of Hg, Se, and Zn in the captive breeding center. In addition, concentrations of As, Co, Cr, and Ni were significantly greater in the sediments of three types of foraging habitats for wild crested ibis, but concentration of Se was greater in the soil of captive cages. Feather and eggshell of crested ibis exhibited a very consistent indication for most of the trace elements, and concentrations of almost all of the elements in the excrements were very consistent with the results in the environmental samples (sediments or soils). Concentrations of As, Hg, Mn, and Zn in feathers, and Mn and Zn in eggshells of wild and captive crested ibis were greater than those in other similar species. Moreover, As, Cd, Cu, and Mn concentrations in excrement of wild crested ibises were greater than that in captive individuals and other species, but Se and Zn concentrations in excrement of captive crested ibises were greater than that of the wild and other species. The present study provided evidence that both of the wild and captive crested ibis were exposed to trace elements, which may be harmful to their health.

An Important Personality Trait Varies with Blood and Plumage Metal Concentrations in a Free-Living Songbird

Metal pollution is a global problem, which threatens to seriously disrupt behavioral patterns and health in humans and wildlife. Nonetheless, little is known regarding how exposure to metal pollution affects animal personalities, as defined by repeatable among individual differences in behavior. We used a large dataset to investigate the relationship between individual blood and feather metal concentrations and three personality traits (exploration behavior, territorial aggressiveness, and aggressiveness during nest defense) in great tits (Parus major), a model species for animal personality research. We previously demonstrated slower exploration behavior at highly polluted study sites, where exposure to lead, cadmium, and arsenic is high. Here, we demonstrate the across-year repeatability of exploration behavior and aggressiveness during nest defense, providing strong evidence for the existence of personalities in our populations. Furthermore, we demonstrate that individuals with high blood lead concentrations and high concentrations of multiple metals in the feathers exhibit slower exploration behavior but no differences in territorial aggressiveness or nest defense relative to less exposed birds. The mechanism underlying the relationship between metal exposure and exploration behavior remains to be determined but could involve neurotoxic effects. Our study highlights that metal pollution could have underappreciated effects on animal personalities, with implications for individual fitness and societal function.

Transgenerational endocrine disruption: Does elemental pollution affect egg or nestling thyroid hormone levels in a wild songbird?

Endocrine disrupting chemicals (EDCs) include a wide array of pollutants, such as some metals and other toxic elements, which may cause changes in hormonal homeostasis. In addition to affecting physiology of individuals directly, EDCs may alter the transfer of maternal hormones to offspring, i.e. causing transgenerational endocrine disruption. However, such effects have been rarely studied, especially in wild populations. We studied the associations between environmental elemental pollution (As, Cd, Cu, Ni, Pb) and maternally-derived egg thyroid hormones (THs) as well as nestling THs in great tits (Parus major) using extensive sampling of four pairs of polluted and reference populations across Europe (Finland, Belgium, Hungary, Portugal). Previous studies in these populations showed that breeding success, nestling growth and adult and nestling physiology were altered in polluted zones compared to reference zones. We sampled non-incubated eggs to measure maternally-derived egg THs, measured nestling plasma THs and used nestling faeces for assessing local elemental exposure. We also studied whether the effect of elemental pollution on endocrine traits is dependent on calcium (Ca) availability (faecal Ca as a proxy) as low Ca increases toxicity of some elements. Birds in the polluted zones were exposed to markedly higher levels of toxic elements than in reference zones at the populations in Finland, Belgium and Hungary. In contrast to our predictions, we did not find any associations between overall elemental pollution, or individual element concentrations and egg TH and nestling plasma TH levels. However, we found some indication that the effect of metals (Cd and Cu) on egg THs is dependent on Ca availability. In summary, our results suggest that elemental pollution at the studied populations is unlikely to cause overall TH disruption and affect breeding via altered egg or nestling TH levels with the current elemental pollution loads. Associations with Ca availability should be further studied.

Personality and plasticity in neophobia levels vary with anthropogenic disturbance but not toxic metal exposure in urban great tits: Urban disturbance, metal pollution and neophobia

Animal personalities, as defined by repeatable among individual differences in behavior, can vary across urbanization gradients. However, how urbanization affects personalities remains incompletely understood, especially because different urban stressors could affect personality traits in opposing ways, whereas most previous studies have considered only one urban disturbance factor. For instance, novel habitat features could favor reduced neophobia, whereas exposure to pollutants could increase risk sensitivity through neurotoxic or hormonal effects. To address this contingency, we studied object neophobia in four urban populations of great tits (Parus major) that vary in exposure to metal pollution and anthropogenic disturbance, as quantified by proximity to roads and pathways. We measured the return latency of incubating females when flushed from the nest and presented with up to two different novel objects, allowing quantification of behavioral repeatability and plasticity. To separate neophobia from sensitivity to disturbance, we also conducted baseline trials, in which females were flushed but no object was presented. We additionally measured exploration behavior and aggression (hissing) during nest defense, to explore whether suites of behaviors covary with urbanization, and examined whether neophobia affects reproductive success. Sensitivity to disturbance and neophobia were repeatable, and thus represent personality traits. Moreover, females occupying territories near roads and pathways had shorter return latencies during novel object but not baseline trials, suggesting a specific reduction in neophobia in disturbed areas. Plasticity in neophobia also increased with disturbance level. In contrast, metal exposure did not affect neophobia or sensitivity to disturbance, despite negatively correlating with exploration behavior. Neophobia correlated with exploration behavior, but not aggression or reproductive success. Results suggest that shifts in personality types in urbanized areas might involve specific reductions in neophobia, rather than general reductions in sensitivity to disturbance, and unexpectedly indicate no effect of toxic metals on risk sensitivity.

Variation in PFAA concentrations and egg parameters throughout the egg-laying sequence in a free-living songbird (the great tit, Parus major): Implications for biomonitoring studies

Over the past decades, there has been growing scientific attention and public concern towards perfluoroalkyl acids (PFAAs), due to their widespread presence in the environment and associations with adverse effects on various organisms. Bird eggs have often been used as less-invasive biomonitoring tools for toxicological risk assessments of persistent organic pollutants, including some PFAAs. Hereby, it is typically assumed that one random egg is representative for the PFAA concentrations of the whole clutch. However, variation of PFAA concentrations within clutches due to laying sequence influences can have important implications for the egg collection strategy and may impede interpretations of the quantified concentrations. Therefore, the main objective of this paper was to study variation patterns and possible laying sequence associations with PFAA concentrations in eggs of the great tit (Parus major). Eight whole clutches (4-8 eggs) were collected at a location in the Antwerp region, situated about 11 km from a known PFAA point source. The ∑ PFAA concentrations ranged from 8.9 to 75.1 ng g^-1 ww. PFOS concentrations ranged from 6.7 to 55.1 ng g^-1 ww and this compound was the dominant contributor to the total PFAA profile (74%), followed by PFDoA (7%), PFOA (7%), PFDA (5%), PFTrA (4%) and PFNA (3%). The within-clutch variation (70.7%) of the ∑ PFAA concentrations was much larger than the among-clutch variation (29.3%) and concentrations decreased significantly for some PFAA compounds throughout the laying sequence. Nevertheless, PFAA concentrations were positively and significantly correlated between some egg pairs within the same clutch, especially between egg 1 and egg 3. For future PFAA biomonitoring studies, we recommend to consistently collect the same egg along the laying sequence, preferably the first or third egg if maximizing egg exposure metrics is the main objective.

Limited reproductive impairment in a passerine bird species exposed along a perfluoroalkyl acid (PFAA) pollution gradient

Although bird eggs have been used in biomonitoring studies on perfluoroalkyl acids (PFAAs), effects of environmental concentrations on reproduction remain largely unknown in wild birds. In the present study we examined the associations between the concentrations of 4 perfluoroalkyl sulfonic acids (PFSAs) and 11 perfluoroalkyl carboxylic acids (PFCAs) in the eggs of great tits (Parus major), collected along a distance gradient from a pollution source, and multiple reproductive parameters (including the start of egg laying, clutch size, hatching success, fledging success and total breeding success) along with egg shell thickness and body condition of the nestlings. The PFAA concentrations measured at the plant site were among the highest ever reported in wild bird eggs. PFAA concentrations decreased sharply with increasing distance (0-11 km) from the plant, but remained relatively elevated in the adjacent sites. PFAAs were grouped into principal components (PCs) to prevent collinearity. High concentrations of PFOS, PFDS, PFDoDA, PFTrDA and PFTeDA (grouped as PC1) were associated with a reduced hatching success of nests where at least one egg hatched, thinner egg shells and increased survival of the hatched chicks. High concentrations of PFDA (PC2) were associated with a reduced hatching success, especially in nests where no eggs hatched, an earlier start of egg laying and a reduction of total breeding success, mainly caused by the failure in hatching. Although the major manufacturer of PFAAs phased out the production of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA) and related products in 2002, concentrations appear to have increased since previous measurements. Surprisingly, despite the very high concentrations close to the fluorochemical plant, there was no clear evidence for reproductive impairment as the observed associations between PFAA concentrations and reproductive parameters were rather limited compared to previous studies in songbirds. These findings also suggest potential differences in sensitivity between species. CAPSULE: Despite the very high PFAA concentrations at the perfluorochemical hotspot, correlations with reproductive parameters were limited.

Assessment of the exposure to heavy metals and arsenic in captive and free-living black kites (Milvus migrans) nesting in Portugal

Due to their high trophic level, raptor species may serve as important indicators of environmental contamination by heavy metals. This study was conducted to determine if the habitat of the black kite (Milvus migrans) is contaminated by heavy metals and arsenic and to assess the degree and type of exposure that may be present. For this purpose, this study was conducted on a group of captive birds (n = 12) and on a group of free-living birds admitted to two wildlife rehabilitation centers (n = 31). Blood samples were taken for analysis of arsenic (As), mercury (Hg) and lead (Pb) concentrations by inductively coupled plasma mass spectrometry (ICP-MS). Captive birds had the lowest blood concentrations for all toxic elements examined, but significant differences from the concentrations found in free-living birds were only observed for Hg and Pb (p < 0.01). Arsenic concentrations were almost three times higher in free-living birds (4.521 ± 5.695 µg/dl) then in captive birds (1.566 ± 0.753 µg/dl). In all the samples of captive birds' mercury was not detected, while in free-living birds we observed a concentration of 7.493 ± 8.464 µg/dl (p < 0.01). Regarding lead, we observed a concentration almost four-fold higher in free-living birds (19.430 ± 29.294 µg/dl) then in captive birds (4.449 ± 1.987 µg/dl) (p < 0.01). Therefore, available sources of Pb and Hg seem to be present in the habitat of the black kite.

Evidence for exposure to selenium by breeding interior snowy plovers (Charadrius nivosus) in saline systems of the Southern Great Plains

Interior snowy plover (Charadrius nivosus) population declines and deteriorating conditions throughout the Southern Great Plains (SGP) of Texas, New Mexico, and Oklahoma may be linked to environmental contaminants. Concentrations of V, As, Cd, Pb, and Se were quantified in breeding snowy plover blood, feathers (5th primary; P5), and potential prey (tiger beetles [Cicindela circumpicta and C. togata]). Se was (a) most commonly detected relative to other quantified elements and (b) frequently quantified at levels exceeding background or toxicity thresholds. Of samples greater than instrumentation detection limits, 98% of snowy plover blood and 22% of feather samples were greater than Se toxicity thresholds of 1 ppm ww for blood and 5 ppm dw for feathers (blood quantifiable range: 0.83-15.12 ppm; feathers quantifiable range: 1.90-27.47 ppm). Almost all tiger beetle Se concentrations were below reported invertebrate thresholds of 30 ppm dw (quantifiable range: 0.54-45.84 ppm). Snowy plover blood Se concentrations were related to sex, individual body condition, and local tiger beetle Se concentrations, while plover P5 Se concentrations were related to state, sex, and presence of body molt. Tiger beetle Se concentrations were related to individual study sites in Texas. These results provide some of the first evidence of Se exposure risk for interior snowy plovers nesting in saline lake and alkali flat environments of the SGP. Future efforts should focus upon specific Se uptake pathways during breeding and nonbreeding seasons, as snowy plovers breeding in the SGP appear to be exposed to Se throughout their annual cycle.

Variation in personality traits across a metal pollution gradient in a free-living songbird

Anthropogenic contaminants could alter traits central to animal behavioral types, or personalities, including aggressiveness, boldness and activity level. Lead and other toxic metals are persistent inorganic pollutants that affect organisms worldwide. Metal exposure can alter behavior by affecting neurology, endocrinology, and health. However, the direction and magnitude of the behavioral effects of metal exposure remain equivocal. Moreover, the degree to which metal exposure simultaneously affects suites of correlated behavioral traits (behavioral syndromes) that are controlled by common mechanisms remains unclear, with most studies focusing on single behaviors. Using a model species for personality variation, the great tit (Parus major), we explored differences in multiple behavioral traits across a pollution gradient where levels of metals, especially lead and cadmium, are elevated close to a smelter. We employed the novel environment exploration test, a proxy for variation in personality type, and also measured territorial aggressiveness and nest defense behavior. At polluted sites birds of both sexes displayed slower exploration behavior, which could reflect impaired neurological or physiological function. Territorial aggression and nest defense behavior were individually consistent, but did not vary with proximity to the smelter, suggesting that metal exposure does not concurrently affect exploration and aggression. Rather, exploration behavior appears more sensitive to metal pollution. Effects of metal pollution on exploration behavior, a key animal personality trait, could have critical effects on fitness.

Metal concentrations in homing pigeon lung tissue as a biomonitor of atmospheric pollution

Atmospheric pollution in urban areas is a major worldwide concern with potential adverse impacts on wildlife and humans. Biomonitoring can provide direct evidence of the bioavailability and bioaccumulation of toxic metals in the environment that is not available with mechanical air monitoring. The current study continues our evaluation of the usefulness of homing pigeon lung tissue as a biomonitor of atmospheric pollution. Homing pigeons (1-2, 5-6, and 9-10+ year old (yo)) collected from Guangzhou during 2015 were necropsied and concentrations of cadmium (Cd), lead (Pb), and mercury (Hg) were measured in lung tissue. Lung Cd and Pb concentrations were significantly greater in 9-10+-year-old pigeons compared with those in other age groups, indicating their bioavailability and bioaccumulation. Lung Pb and Cd concentrations measured in 5-yo pigeons collected from Guangzhou during 2015 were significantly lower than concentrations reported in 5-yo homing pigeons collected from Guangzhou during 2011 and correlated with concentrations measured using mechanical air monitoring. In addition to temporal differences, spatial differences in concentrations of Cd, Pb, and Hg reported in ambient air samples and in pigeon lung tissues collected from Beijing and Guangzhou are discussed.

Artificial light at night causes an unexpected increase in oxalate in developing male songbirds

Artificial light at night (ALAN) is a widespread and increasing environmental pollutant with known negative impacts on animal physiology and development. Physiological effects could occur through sleep disruption and deprivation, but this is difficult to quantify, especially in small developing birds. Sleep loss can potentially be quantified by using oxalate, a biomarker for sleep debt in adult humans and rats. We examined the effect of ALAN on oxalate in free-living developing great tits (Parus major) as effects during early-life could have long-lasting and irreversible consequences. Nestlings' physiology was quantified at baseline (= 13 days after hatching) and again after two nights of continued darkness (control) or exposure to ALAN (treatment). We found that ALAN increased oxalate levels but only in male nestlings, rather than decreasing it as was found in sleep-deprived humans and rats. Our results using developing birds differ strongly from those obtained with adult mammals. However, we used ALAN to reduce sleep while in rats forced movement was used. Finally, we used free-living opposed to laboratory animals. Whether oxalate is a reliable marker of sleep loss in developing great tits remains to be examined. Potentially the increase of oxalate in male nestlings was unrelated to sleep debt. Nonetheless, our results substantiate physiological effects of ALAN in developing animals and may provide a foundation for future work with free-living animals.

Associations of urban environmental pollution with health-related physiological traits in a free-living bird species

Urban environmental pollution results in contamination of the tissues of synanthropic organisms by toxic trace elements with potential impacts on human health. Passerine birds may serve as convenient indicators of such contamination. In this study we investigated the effect of blood and plumage contamination with heavy metals (lead Pb, cadmium Cd, copper Cu, chromium Cr) and arsenic metalloid (As) on condition, health and ornamental colour in free-living great tit (Parus major) males from 13 cities across the Czech Republic (EU), mist netted during the early breading season (April-May). Our results showed a significant association of heavy metal tissue contamination with immune function, namely leukocyte composition in the avian blood circulation. High heavy metal contamination in bird feathers was linked to a high heterophil/lymphocyte (H/L) ratio, indicating long-term stress in individuals inhabiting heavily polluted environments. In contrast, males with higher concentrations of heavy metals in blood had a lower H/L ratio, assumingly due to the direct toxicity of heavy metals in certain cell types. This is also supported by traits indicative of anaemia-like haemolytic conditions (decreased absolute erythrocyte count) and increased haematopoiesis (a tendency for increased frequencies of immature erythrocytes). We did not find any association of heavy metal contamination with the bacteriolytic activity of plasma complement, feather growth or ornamentation (black breast stripe area and yellow colouration). There was no significant relationship between heavy metal contamination in blood or feathers and PM₁₀ pollution at the study sites. Our correlational study is the first to show on a large geographic scale that despite strict European air pollution regulations and regular monitoring that have allowed general improvements in atmospheric contamination, non-degradable heavy metals persistently contaminate animal blood and feathers in anthropogenic environments at levels that may have subclinical yet physiological effects with varied influence on health.

Artificial light at night affects sleep behaviour differently in two closely related songbird species

Artificial light at night (ALAN) or light pollution is an increasing and worldwide problem. There is growing concern that because of the disruption of natural light cycles, ALAN may pose serious risks for wildlife. While ALAN has been shown to affect many aspects of animal behaviour and physiology, few studies have experimentally studied whether individuals of different species in the wild respond differently to ALAN. Here, we investigated the effect of ALAN on sleep behaviour in two closely related songbird species inhabiting the same study area and roosting/breeding in similar nest boxes. We experimentally exposed free-living great tits (Parus major) and blue tits (Cyanistes caeruleus) to artificial light inside their nest boxes and observed changes in their sleep behaviour compared to the previous night when the nest boxes were dark. In line with previous studies, sleep behaviour of both species did not differ under dark conditions. ALAN disrupted sleep in both great and blue tits. However, compared to blue tits, great tits showed more pronounced effects and more aspects of sleep were affected. Light exposed great tits entered the nest boxes and fell asleep later, woke up and exited the nest boxes earlier, and the total sleep amount and sleep percentage were reduced. By contrast, these changes in sleep behaviour were not found in light exposed blue tits. Our field experiment, using exactly the same light manipulation in both species, provides direct evidence that two closely related species respond differently to ALAN, while their sleep behaviour under dark conditions was similar. Our research suggests that findings for one species cannot necessarily be generalised to other species, even closely-related species. Furthermore, species-specific effects could have implications for community dynamics.

Perfluoroalkylated acids in the eggs of great tits (Parus major) near a fluorochemical plant in Flanders, Belgium

Perfluoroalkyl acids (PFAAs) are highly persistent substances which have been detected in wildlife around the world, including birds. Although bird eggs have often been used to determine and monitor PFAAs levels in the marine environment, this has rarely been done in the terrestrial environment. In the present study we examined the concentrations and composition profile of 12 PFAAs (4 perfluoroalkyl sulfonic acids (PFSAs) and 8 perfluoroalkyl carboxylic acids (PFCAs) in the eggs of great tits (Parus major) collected at a fluorochemical plant and in three other areas, representing a gradient in distance from the pollution source (from 1 to 70 km), in Antwerp, Belgium. The PFSA concentrations measured at the site of the fluorochemical plant were among the highest ever reported in eggs with median concentrations of 10380 ng/g (extrapolated), 99.3 ng/g and 47.7 ng/g for PFOS, PFHxS and PFDS respectively. Furthermore, the median concentration of 19.8 ng/g for PFOA was also among the highest ever reported in bird eggs. Although these concentrations decreased sharply with distance from the fluorochemical plant, levels found in the adjacent sites were still high compared to what has been reported in literature. Moreover, based on what is known in literature, it is likely that these concentrations may cause toxicological effects. PFOS was the dominant contributor to the PFSA and PFAAs (63.4-97.6%) profile at each site, whereas for PFCAs this was PFOA at the plant site and the nearest locations (41.0-52.8%) but PFDoA (37.7%) at the farthest location. Although there is some evidence that PFAAs concentrations close to the plant site are decreasing in comparison with earlier measurements, which may be due to the phase out of PFOS, more research is necessary to understand the extent of the toxicological effects in the vicinity of this PFAAs hotspot.

Heavy metal bioaccumulation in two passerines with differing migration strategies

Various anthropogenic activities have resulted in concentration of heavy metals and contamination of surrounding environments. Historically, heavy metal contamination at the Savannah River Site (SRS) in South Carolina has resulted from accidental releases of stored waste generated from nuclear weapon production in the early 1950s. Songbirds inhabiting and using resources from these areas have the potential to bioaccumulate metals but there is limited information on metal concentration levels in areas suspected of contamination as well as uncontaminated sites. Nonlethal tissues samples from avian blood and feathers provide a reliable approach for determining the bioavailability of these pollutants (As, Cd, Cr, Cu, Hg, Ni, Pb, Se, and Zn). The objectives of this study were to survey terrestrial heavy metal contamination at the SRS on potentially bioavailable contaminated (PBC) sites through blood and feather samples from resident Northern Cardinals (Cardinalis cardinalis) and migratory Great Crested Flycatchers (Myiarchus crinitus) and quantify sex-specific concentrations within species. Samples were collected in April to June of 2016. Cardinals had lower blood concentrations of Hg (β=-0.17, 85% CL=-0.26, -0.09) and Se (β=-0.33, 85% CL=-0.50, -0.16) than flycatchers. Cr feather concentrations were less in cardinals (β=-1.46, 85% CL=-2.44, -0.49) and all feathers of both species from reference locations had significantly less Zn (β=-67.92, 85% CL=-128.71, -7.14). Results indicate flycatchers were exposed to differing heavy metal levels during feather formation on their wintering grounds as compared to their recent exposure (through bloods samples) on their breeding grounds. Sex of individuals did not have a significant impact on bioaccumulation in either species. Overall, metal concentration levels in both species indicate minimal risk for acute toxicity; however, there is limited research on wild passerine populations with similar concentration levels. Therefore, further research on reproductive success of these birds should be explored.

Great tit response to decreasing industrial heavy metal emissions

This study evaluated the effects of environmental pollution on decreasing great tit (Parus major) breeding parameters in an industrial area in the west coast of Portugal. Several great tit breeding parameters were monitored in the industrial area, as well as in a rural area not affected by industrial emissions. Low levels of air pollution in both industrial and rural areas were confirmed by assessing trace element concentrations in pine needles. Concentrations of Cd and Hg in pine needles from the industrial area (Cd = 0.05 ppm; Hg = 0.005 ppm) were significantly lower than those found in needles collected from the reference area (Cd = 0.07 ppm; Hg = 0.007 ppm). Additionally, the breeding success of great tits increased in the industrial area in comparison to the reference area (0.93 ± 0.08 and 0.62 ± 0.22, respectively). The changes on great tit breeding parameters were probably related with changes in the breeding density of other competitive species, together with a decreasing frass-fall biomass. Further long-term ecological studies in industrial areas are necessary to understand the changing breeding performance and strategies used by great tits in response to pollution shifts in the environment.

High levels of PFOS in eggs of three bird species in the neighbourhood of a fluoro-chemical plant

We studied perfluorooctane sulfonate (PFOS) levels in the eggs of three primarily invertivorous bird species sampled in 2006 near a fluoro-chemical plant: the great tit (Parus major), the northern lapwing (Vanellus vanellus) and the Mediterranean gull (Larus melanocephalus). Our study reported some of the highest PFOS levels ever measured in wildlife to date (i.e. up to 46182ng/g ww in lapwing eggs). A pronounced decrease in PFOS concentration in the Northern lapwing eggs with distance from the fluoro-chemical plant was found. A similar relationship was found for the great tit, with eggs being collected close to the fluoro-chemical plant having significantly higher PFOS levels than eggs collected 1700m further away. When comparing the PFOS levels in eggs for the three species, collected between 1700 and 5500m no significant differences were observed. In addition, when comparing PFOS levels in eggs between Northern lapwing and great tits closer to the plant (900-1700m) no significant differences were found neither. Despite the high levels found in great tit eggs, plasmatic biochemical biomarker responses did not appear to be affected.

The use of feather as an indicator for heavy metal contamination in house crow (Corvus splendens) in the Klang area, Selangor, Malaysia

The Klang area of Peninsular Malaysia has experienced rapid industrial growth with intense activities, which can increase the concentration of pollutants in the environment that significantly impact on habitats and the human health. The purpose of this study was to determine the levels of selected heavy metals (Cu, Zn, Ni, Fe, and Pb) in the heart, lung, brain, liver, kidney, muscle tissues, and feathers of house crow, Corvus splendens, in Klang, Peninsular Malaysia. House crow samples were collected from the Klang area through the Department of Public Health at Majlis Perbandaran Klang. Quantitative determination of heavy metals was carried out using atomic absorption spectrophotometer (AAS). The result shows the presence of heavy metals in all biological samples of house crows. For heavy metals in all the house crow tissues analyzed, Fe concentrations were the highest, followed by those of Zn, Cu, Pb, and Ni. The feathers and kidney accumulated high concentrations of Pb, whereas the liver accumulated high concentrations of essential heavy metals (Fe > Zn > Cu > Ni). Significant variations were also detected in the concentrations of Pb among adult and juvenile and male and female bird samples. The results also revealed significant positive correlations between Pb metal concentration in the breast feathers and all internal organs. Accumulation of toxic heavy metals in feathers reflected storing and elimination processes, while the accumulation of toxic heavy metals in the kidney can be consequential to chronic exposure. The present study clearly shows the usefulness of house crow breast feather as a suitable indicator for heavy metal accumulation in the internal organs of house crows in the Klang area.

Corticosterone levels in relation to trace element contamination along an urbanization gradient in the common blackbird (Turdus merula)

In a rapidly urbanizing world, trace element pollution may represent a threat to human health and wildlife, and it is therefore crucial to assess both exposition levels and associated effects of trace element contamination on urban vertebrates. In this study, we investigated the impact of urbanization on trace element contamination and stress physiology in a wild bird species, the common blackbird (Turdus merula), along an urbanization gradient (from rural to moderately urbanized areas). Specifically, we described the contamination levels of blackbirds by 4 non-essential (Ag, Cd, Hg, Pb) and 9 essential trace elements (As, Co, Cr, Cu, Fe, Mn, Ni, Se, Zn), and explored the putative disrupting effects of the non-essential element contamination on corticosterone levels (a hormonal proxy for environmental challenges). We found that non-essential trace element burden (Cd and Pb specifically) increased with increasing urbanization, indicating a significant trace element contamination even in medium sized cities and suburban areas. Interestingly, the increased feather non-essential trace element concentrations were also associated with elevated feather corticosterone levels, suggesting that urbanization probably constrains birds and that this effect may be mediated by trace element contamination. Future experimental studies are now required to disentangle the influence of multiple urban-related constraints on corticosterone levels and to specifically test the influence of each of these trace elements on corticosterone secretion.

Metals and metalloids in nestling tree swallows and their dietary items near oilsands mine operations in Northern Alberta

Tree swallows (Tachycineta bicolor) nesting near oilsands development in northern Alberta are potentially exposed to elevated levels of metals. The objective of this study was to determine whether levels of metals and metalloid elements in dietary items and tissues of nestling tree swallows inhabiting areas near oilsands mine operations were higher compared to those of reference sites. We hypothesized that if there was increased, industry-related exposure to metals, it would be via the diet. We identified the invertebrate prey in the stomach contents of nestlings. We also collected invertebrates using Malaise traps near nest boxes, and analyzed those taxa found in the nestling diet to understand potential variability in metal exposure. For most elements, we found no significant differences in concentrations in the liver, kidney, or stomach contents between sites near to and far from oilsands operations. Concentrations of five elements were positively correlated among tissues and stomach contents. For invertebrates collected from Malaise traps, location differences occurred in some absolute elemental concentrations, which were most often highest at reference sites away from mining operations. We found no evidence that nestling tree swallows accumulated metals approaching toxic levels. Tree swallows consumed relatively high quantities of terrestrial insects, possibly limiting exposure to water borne, food-web-related contaminants. We suggest that annual variability associated with elemental exposure and dietary levels of elements be considered when interpreting concentrations in bird tissues.

Assessment of Trace Element Concentrations in Birds of Prey in Korea

This study presents liver concentrations of trace elements of cinereous vultures (Aegypius monachus), common buzzards (Buteo buteo), common kestrels (Falco tinnunculus), and Eurasian eagle owls (Bubo bubo) collected in Korea from 2007 to 2008. Iron (Fe), manganese (Mn), copper (Cu), lead (Pb), and cadmium (Cd) concentrations in common kestrel juveniles were greater than in other juveniles of birds of prey. Adult cinereous vultures had greater Fe, Pb, and Cd concentrations than in those of other species, but common kestrels had greater Mn and Cu concentrations than in those of other birds of prey. Zinc concentrations in Eurasian eagle owl juveniles and adults were greater than in juveniles and adults of other species, respectively. In common kestrels, Fe, Cu, Pb, and Cd concentrations were significantly greater in adults than in juveniles. In Eurasian eagle owls, only Pb concentrations were greater in adults than in juveniles. Essential elements, such as Fe, Zn, Mn, and Cu concentrations, were within the range of other birds of prey studies. Seventeen individual birds of prey (30 %) were at a level considered Pb exposed (6-30 µg/g dw). This is a greater proportion than reported earlier in herons, egrets, and other birds from Korea. Elevated Pb concentration might be attributed to ingestion of Pb shot and bullet fragments for cinereous vultures and common buzzards, and urbanization for common kestrels. Cadmium concentrations in birds of prey were within the background concentrations (<3 µg/g dw) for wild birds.

Effects of chemical elements in the trophic levels of natural salt marshes

The relationships between the bioaccumulation of Na, K, Ca, Mg, Fe, Zn, Cu, Mn, Co, Cd, and Pb, acidity (pH), salinity (Ec), and organic matter content within trophic levels (water-soil-plants-invertebrates) were studied in saline environments in Poland. Environments included sodium manufactures, wastes utilization areas, dumping grounds, and agriculture cultivation, where disturbed Ca, Mg, and Fe exist and the impact of Cd and Pb is high. We found Zn, Cu, Mn, Co, and Cd accumulation in the leaves of plants and in invertebrates. Our aim was to determine the selectivity exhibited by soil for nutrients and heavy metals and to estimate whether it is important in elucidating how these metals are available for plant/animal uptake in addition to their mobility and stability within soils. We examined four ecological plant groups: trees, shrubs, minor green plants, and water macrophytes. Among invertebrates, we sampled breastplates Malacostraca, small arachnids Arachnida, diplopods Diplopoda, small insects Insecta, and snails Gastropoda. A higher level of chemical elements was found in saline polluted areas (sodium manufactures and anthropogenic sites). Soil acidity and salinity determined the bioaccumulation of free radicals in the trophic levels measured. A pH decrease caused Zn and Cd to increase in sodium manufactures and an increase in Ca, Zn, Cu, Cd, and Pb in the anthropogenic sites. pH increase also caused Na, Mg, and Fe to increase in sodium manufactures and an increase in Na, Fe, Mn, and Co in the anthropogenic sites. There was a significant correlation between these chemical elements and Ec in soils. We found significant relationships between pH and Ec, which were positive in saline areas of sodium manufactures and negative in the anthropogenic and control sites. These dependencies testify that the measurement of the selectivity of cations and their fluctuation in soils provide essential information on the affinity and binding strength in these environments. The chemical elements accumulated in soils and plants; however, further flow is selective and variable. The selectivity exhibited by soil systems for nutrients and heavy metals is important in elucidating how these metals become available for plant/animal uptake and also their mobility and stability in soils.

Use of homing pigeons as biomonitors of atmospheric metal concentrations in Beijing and Guangzhou, China

Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment and in the current study, homing pigeons were used as a biomonitor of atmospheric pollution in Beijing and Guangzhou, China. Cadmium (Cd), lead (Pb), and mercury (Hg) concentrations were measured in lung, kidney, and liver tissues of 25 homing pigeons collected from Beijing (n = 15) and Guangzhou (n = 10). Cadmium concentrations in all tissue and lung Pb concentrations were significantly greater in pigeons collected from Guangzhou compared to those collected from Beijing. Lung Cd and Pb concentrations corresponded to differences in ambient air concentrations between the two cities, suggesting that homing pigeons are valuable biomonitors of atmospheric metal contamination. Liver and kidney Hg concentrations were significantly greater in pigeons collected from Beijing compared to those collected from Guangzhou, while Hg concentrations in lung tissue were not significantly different. Results of the current study support a conclusion that homing pigeons provide valuable data for evaluating exposure and potential effects to environmental metal concentrations.

Effects of breeding habitat (woodland versus urban) and metal pollution on the egg characteristics of great tits (Parus major)

In an urban environment, birds are exposed to metals, which may accumulate in their tissues and cause oxidative stress. Female birds may eliminate these pollutants through depositing them into eggs, thus eggs become suitable bioindicators of pollution. In this study, we aimed to analyse whether eggshell spotting pattern, egg volume, eggshell thickness and egg yolk antioxidant (lutein, tocopherol, retinol and selenium) levels were related to the breeding area (woodland versus urban) and the metal levels in the eggshell of a small passerine species, the great tit (Parus major). In the urban habitat, soil and eggshells contained higher concentrations of metals, and soil calcium level was also higher than that in the woodland. Eggshell spotting intensity and egg volume did not differ between eggs laid in the woodland and the urban park, and these traits were not related to the metal levels of the eggshell, suggesting that these egg characteristics are not sensitive indicators of metal pollution. A more aggregated eggshell spotting distribution indicated a higher Cu concentration of the eggshell. We found that eggshells were thinner in the less polluted woodland habitat, which is likely due to the limited Ca availability of the woodland area. Great tit eggs laid in the urban environment had lower yolk lutein, retinol and selenium concentrations, however, as a possible compensation for these lower antioxidant levels, urban females deposited more tocopherol into the egg yolk. It appears that females from different breeding habitats may provide similar antioxidant protection for their offspring against oxidative damage by depositing different specific dietary antioxidants. Egg yolk lutein and retinol levels showed a negative relationship with lead concentration of the eggshell, which may suggest that lead had a negative impact on the amount of antioxidants available for embryos during development in great tits.

Metals and trace elements in feathers: A geochemical approach to avoid misinterpretation of analytical responses

Assessing trace metal pollution using feathers has long attracted the attention of ecotoxicologists as a cost-effective and non-invasive biomonitoring method. In order to interpret the concentrations in feathers considering the external contamination due to lithic residue particles, we adopted a novel geochemical approach. We analysed 58 element concentrations in feathers of wild Eurasian Greater Flamingo Phoenicopterus roseus fledglings, from 4 colonies in Western Europe (Spain, France, Sardinia, and North-eastern Italy) and one group of adults from zoo. In addition, 53 elements were assessed in soil collected close to the nesting islets. This enabled to compare a wide selection of metals among the colonies, highlighting environmental anomalies and tackling possible causes of misinterpretation of feather results. Most trace elements in feathers (Al, Ce, Co, Cs, Fe, Ga, Li, Mn, Nb, Pb, Rb, Ti, V, Zr, and REEs) were of external origin. Some elements could be constitutive (Cu, Zn) or significantly bioaccumulated (Hg, Se) in flamingos. For As, Cr, and to a lesser extent Pb, it seems that bioaccumulation potentially could be revealed by highly exposed birds, provided feathers are well cleaned. This comprehensive study provides a new dataset and confirms that Hg has been accumulated in feathers in all sites to some extent, with particular concern for the Sardinian colony, which should be studied further including Cr. The Spanish colony appears critical for As pollution and should be urgently investigated in depth. Feathers collected from North-eastern Italy were the hardest to clean, but our methods allowed biological interpretation of Cr and Pb. Our study highlights the importance of external contamination when analysing trace elements in feathers and advances methodological recommendations in order to reduce the presence of residual particles carrying elements of external origin. Geochemical data, when available, can represent a valuable tool for a correct interpretation of the analytical results.

Risk assessment of metals and PAHs for receptor organisms in differently polluted areas in Slovenia

Samples from receptor organisms (small mammals, passerine birds) and their food sources (herbaceous plants, leaves and fruits of wood plants, earthworms) were collected during 2011-2014 from the vicinity of a former lead smelter, from the vicinity of the largest Slovenian thermal power plant, from along a state road and also from a reference area. The samples were then analysed to determine the degree of contamination with the metals (Pb, Cd, Zn, Hg, Cu, Mo) and with polycyclic aromatic hydrocarbons (PAHs). This study provides the first data on metal and PAH exposure to small mammals and passerine birds in southeast Europe, focussing on the transfer of metals and PAHs through the food chain and on risk assessment for differently polluted areas in Slovenia. The results indicate that: (i) earthworms and herbaceous plants (especially roots) can be a source of metal exposure for organisms higher in the food chain; (ii) a risk from Pb and Cd (HQ > 1) in the vicinity of the former lead smelter exists for Myodes glareolus feeding in part on roots and for Apodemus flavicollis and Parus major feeding in part on earthworms; and (iii) mean Pb and Cd concentrations in the liver of small mammal species inhabiting the vicinity of the lead smelter reach effect concentrations in a significant proportion of the specimens (Pb: 40%, Cd: 67%); (iv) the results for P. major confirm that the study area is exposed to Pb, Cd, Hg; (v) metals contribute the major part of the total risk for receptor organisms from vicinity of lead smelter. On the contrary, the risk of PAHs for small mammals trapped close to the state road is insignificant. We can summarize, that the hazards experienced by the local ecosystem due to metal exposure may persist for decades in the vicinity of large emission sources (especially smelters).

Trace element contamination in nestling black-tailed gulls (Larus crassirostris) in Korea

At Hongdo Island, Gyeongsangnam-do, Korea, a breeding site of black-tailed gull (Larus crassirostris), we collected nestlings from two locations: a "reference" site (n = 10) with no known source of lead contamination and "lighthouse" site (n = 10) with suspected lead contamination from leaded paint. Iron concentrations in the kidney and bone, manganese in the muscle, copper in the bone, lead in the muscle and bone, and cadmium in the liver, muscle, and bone at the reference site were significantly higher than at the lighthouse. Manganese concentrations in the liver and kidney, and lead in the kidney were significantly greater at the lighthouse than at the reference site. Iron, zinc, manganese, copper, lead and cadmium concentrations had tissue-specific accumulation at both sites. Lead concentrations in 10 % of livers and in 80 % of kidneys at the lighthouse, and in 20 % of livers from the reference were within a range considered toxic (>6.00 μg/g dw in the liver and kidney). Lead concentrations in 50 % of black-tailed gull nestlings at the reference and 80 % nestlings at the lighthouse were greater in livers than in bones, which is suggestive of acute lead exposure. For cadmium, all liver and kidney concentrations from two sites were at a level considered background in birds. Cadmium concentrations of every sample were higher in kidneys than in livers, suggestive of chronic cadmium exposure. Lead concentrations in gull nestlings in the present study were relatively higher than other gull species worldwide, but cadmium concentrations were relatively lower.

A review on exposure and effects of arsenic in passerine birds

Arsenic (As) is a metalloid of high concern because of its toxic effects for plants and animals. However, it is hard to find information on this metalloid in passerines. This review presents a comprehensive overview of As exposure and effects in birds, and more particularly in passerines, as a result of an extensive search of the literature available. Internal tissues are the most frequently analyzed matrices for As determination in passerines (37.5% of the reviewed studies used internal tissues), followed by feathers and eggs (32.5% each), feces (27.5%), and finally blood (15%). A clear tendency is found in recent years to the use of non-destructive samples. Most studies on As concentrations in passerines have been done in great tit (Parus major; 50%), followed by pied flycatcher (Ficedula hypoleuca; 22.5%). Some factors such as diet and migratory status are crucial on the interspecific differences in As exposure. More studies are needed to elucidate if intraspecific factors like age or gender affect As concentrations in different tissues. The literature review shows that studies on As concentrations in passerines have been done mainly in the United States (30%), followed by Belgium (22.5%), and Finland (20%), making evident the scarce or even lack of information in some countries, so we recommend further research in order to overcome the data gap, particularly in the southern hemisphere. Studies on humans, laboratory animals and birds have found a wide range of effects on different organ systems when they are exposed to different forms of As. This review shows that few field studies on As exposure and effects in passerines have been done, and all of them are correlative so far. Arsenic manipulation experiments on passerines are recommended to explore the adverse effects of As in free-living populations at similar levels to those occurring in the environment.

CAPSULE

This review summarizes the most interesting published studies on As exposure and effects in passerines.

Influence of taxa, trophic level, and location on bioaccumulation of toxic metals in bird's feathers: a preliminary biomonitoring study using multiple bird species from Pakistan

Increasing concentrations of heavy metals in the environment and their effects on ecosystems and biota is still an imminent threat, particularly in developing parts of the globe. The aim of the present study was to screen the heavy metal concentrations in multiple bird species across Pakistan and to preliminary evaluate the influence of taxa, trophic level, and geographical location on heavy metal accumulation in various bird species. For this purpose, we measured the concentration of 9 heavy metals (Pb, Cd, Cr, Ni, Co, Cu, Fe, Zn and Mn) in feathers of 48 bird species from different localities in Pakistan. Species exhibited heterogeneous levels of heavy metals in feathers with marked inter and intra specific variations. Mean concentrations of studied metals in feathers followed the trend Fe>Zn>Cu>Pb>Mn>Cr>Ni>Co>Cd. Species belonging to closely related taxa (families) showed comparable metal concentrations in their feathers, inferring potential phylogenetic similarities in metal exposure or accumulation. In general, concentrations of metals were greatest in carnivorous species followed by omnivorous and insectivorous birds, and granivores showing minimal levels (p<0.000). Furthermore, concentrations of metals varied significantly between locations (p<0.000) exhibiting highest concentrations in Punjab province and Baluchistan, probably due to higher industrial and agricultural activity and runoff, respectively. With certain limitation, influence of trophic level, taxonomic affiliation and sampling location of birds on toxic metal accumulation was also statistically corroborated through principal component analysis (PCA). This study highlights that despite restricted emissions, heavy metals persist in the local environment and may pose elevated risks for the studied bird species in Pakistan.

Avian feathers as a non-destructive bio-monitoring tool of trace metals signatures: a case study from severely contaminated areas

The concentrations of trace metals were assessed using feathers of cattle egrets (Bubulcus ibis), collected within two industrial areas of Pakistan, Lahore and Sialkot. We found, in order of descending concentration: Zinc (Zn), Iron (Fe), Nickel (Ni), Copper (Cu), Cadmium (Cd), and Manganese (Mn), Chromium (Cr), Arsenic (As), and Lithium (Li), without any significant difference (except Fe, Zn, and Ni) between the two areas. The concentrations of trace metals, we recorded were among the highest ever reported in the feathers of avian species worldwide. The concentrations of Cr, Pb, Cd were above the threshold that affects bird reproductive success. The high contamination by heavy metals in the two areas is due to anthropogenic activities as well to natural ones (for As and Fe). The bioaccumulation ratios in eggs and feathers of the cattle egret, their prey, and the sediments from their foraging habitats, confirmed that avian feathers are a convenient and non-destructive sampling tool for the metal contamination. The results of this study will contribute to the environmental management of the Lahore and Sialkot industrial areas.

Concentration of trace elements in feathers of waterfowl, Korea

Cadmium (Cd), lead (Pb), chromium (Cr), copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) were analyzed in the breast feather of white-fronted geese (Anser albifrons, n = 15), mallards (Anas platyrhynchos, n = 4), and spot-billed ducks (Anas poecilorhyncha, n = 13) found dead in Gimpo, Korea. All of the mallards and eight of the 13 spot-billed ducks had embedded shot. Concentrations of Pb, Cr, Cu, Mn, Zn, and Fe were significantly different among waterfowl species. Mallards with embedded shot had relatively higher Pb, Cr, Mn, and Fe concentrations than the other species. Cd and Cr in feathers of waterfowl species were within the range reported for other birds, and no specimen exceeded the tentative threshold effect levels of Cd (2 μg/g dry weight (dw)) and Cr (2.8 μg/g dw) for birds. However, Pb in feathers of all four mallards and two spot-billed ducks exceeded the threshold for deleterious effects (>4 μg/g dw). Essential elements such as Cu, Mn, Zn, and Fe in the feather of waterfowl species were not at toxic levels and within the background or normal range for the homeostatic mechanisms.

Spatial and temporal variation of lead, cadmium, and zinc in feathers of great tit and blue tit nestlings in Central Poland

In this study, we examined heavy-metal concentrations in feathers of nestling great tits Parus major and blue tits Cyanistes caeruleus at two different sites (urban parkland vs. deciduous forest) located in the Łódź agglomeration in relation to interyear variation. We found that tit species did not differ significantly in lead and cadmium concentrations. Zinc concentration was significantly higher in blue tits. We also found that lead and cadmium levels in blue tit nestlings and the level of lead in great tit nestlings were higher in the parkland site than in the woodland site. We explain habitat variation in heavy-metal concentrations in feathers of nestlings by different levels of contamination at study sites. For both tit species, significant variation in heavy-metal amounts accumulated by nestlings was found between years with the lowest value in a year with the lowest value of rainfall. We suggest that the interyear variation may be accounted for by differences in rainfall, thus influencing quantities of trace elements bioavailable in the environment.

Assessment of lead exposure in waterfowl species, Korea

Lead concentrations were analyzed in white-fronted geese (Anser albifrons, n = 15), mallards (Anas platyrhynchos, n = 4), and spot-billed ducks (A. poecilorhyncha, n = 13) found dead near Gimpo, Korea, to determine tissue- and species-specific lead concentration differences and to assess the effect of embedded lead shot. In livers, kidneys, and bones (tarsus), mallards and spot-billed ducks with embedded shot had greater lead concentrations than white-fronted geese and spot-billed ducks without lead shot. Lead concentrations in spot-billed ducks were greater in bones than in livers and kidneys suggesting chronic exposure to lead. Lead concentrations in 8 of 32 livers, 5 of 32 kidneys, and 9 of 32 bones exceeded the threshold level of abnormal exposure for wild birds (>5 µg/g dw in lives, >6 µg/g dw in kidney, and >6.75 µg/g dw in bone). Increased lead concentrations in soft tissues and bones might be attributed to increased lead shot ingestion and embedded shot. Lead concentrations were correlated between livers and kidneys, between livers and bones, and between kidneys and bones. These results suggest that a relationship between acute exposure in livers and kidneys and chronic exposure in bones.

Effect of the environmental quality and food chain on trace element concentrations in Heron and Egret chicks at Pyeongtaek colony, Korea

Trace element concentrations in the diet can affect the levels in birds. Heron and egret chicks have been recommended as useful biological indicators for monitoring trace element contamination in the aquatic ecosystem. Iron, zinc, manganese, copper, lead and cadmium concentrations were measured in the livers and stomach contents of Grey Heron (Ardea cinerea), Intermediate Egret (Egretta intermedia), Little Egret (Egretta garzetta) and Black-crowned Night Heron (Nycticorax nycticorax) chicks from Pyeongtaek colony, Korea in 2008. Iron, zinc, manganese, copper and cadmium concentrations in livers differed among four heron and egret species. Stomach content concentrations of iron, zinc, copper, lead and cadmium concentrations differed among the four species. Essential elements such as iron, zinc, manganese and copper concentrations were within the range of other heron and egret studies and these levels may be regulated by a normal homeostatic mechanism. Two of 11 (18.2%) Grey Heron and two of 10 (20.0%) Black-crowned Night Heron chicks exceeded the background lead level (<6 µg/g dw) for birds and were at a level considered lead exposed (6-30 µg/g dw). Cadmium concentrations did not exceed the background levels for wild birds. In livers of combined heron and egret chicks, lead, but not cadmium concentrations were associated with concentrations in the stomach contents. These results suggest that lead concentrations in chicks can reflect qualities of feeding area such as streams, rivers and paddy fields and chicks represent a bioindicator to evaluate lead contamination in aquatic ecosystems.

The distribution and extent of heavy metal accumulation in song sparrows along Arizona's upper Santa Cruz River

Heavy metals are persistent environmental contaminants, and transport of metals into the environment poses a threat to ecosystems, as plants and wildlife are susceptible to long-term exposure, bioaccumulation, and potential toxicity. We investigated the distribution and cascading extent of heavy metal accumulation in southwestern song sparrows (Melospiza melodia fallax), a resident riparian bird species that occurs along the US/Mexico border in Arizona's upper Santa Cruz River watershed. This study had three goals: (1) quantify the degree of heavy metal accumulation in sparrows and determine the distributional patterns among study sites, (2) compare concentrations of metals found in this study to those found in studies performed prior to a 2009 international wastewater facility upgrade, and (3) assess the condition of song sparrows among sites with differing potential levels of exposure. We examined five study sites along with a reference site that reflect different potential sources of contamination. Body mass residuals and leukocyte counts were used to assess sparrow condition. Birds at our study sites typically had higher metal concentrations than birds at the reference site. Copper, mercury, nickel, and selenium in song sparrows did exceed background levels, although most metals were below background concentrations determined from previous studies. Song sparrows generally showed lower heavy metal concentrations compared to studies conducted prior to the 2009 wastewater facility upgrade. We found no cascading effects as a result of metal exposure.

Large-scale geographical variation in eggshell metal and calcium content in a passerine bird (Ficedula hypoleuca)

Birds have been used as bioindicators of pollution, such as toxic metals. Levels of pollutants in eggs are especially interesting, as developing birds are more sensitive to detrimental effects of pollutants than adults. Only very few studies have monitored intraspecific, large-scale variation in metal pollution across a species' breeding range. We studied large-scale geographic variation in metal levels in the eggs of a small passerine, the pied flycatcher (Ficedula hypoleuca), sampled from 15 populations across Europe. We measured 10 eggshell elements (As, Cd, Cr, Cu, Ni, Pb, Zn, Se, Sr, and Ca) and several shell characteristics (mass, thickness, porosity, and color). We found significant variation among populations in eggshell metal levels for all metals except copper. Eggshell lead, zinc, and chromium levels decreased from central Europe to the north, in line with the gradient in pollution levels over Europe, thus suggesting that eggshell can be used as an indicator of pollution levels. Eggshell lead levels were also correlated with soil lead levels and pH. Most of the metals were not correlated with eggshell characteristics, with the exception of shell mass, or with breeding success, which may suggest that birds can cope well with the current background exposure levels across Europe.

Age-dependent accumulation of heavy metals in liver, kidney and lung tissues of homing pigeons in Beijing, China

Biomonitoring provides direct evidence of the bioavailability and accumulation of toxic elements in the environment. In the current study, 1-2, 5-6, and 9-10+ year old homing pigeons collected from the Haidian District of Beijing during 2011 were necropsied and concentrations of cadmium, lead, and mercury were measured in liver, lung, and kidney tissue. At necropsy, gray/black discoloration of the margins of the lungs was observed in 98 % of the pigeons. There were no significant differences in metal concentrations as a function of gender. Cadmium concentrations in all tissues and Pb concentrations in the lung tissues were significantly greater in 9-10+ year old pigeons compared to other age groups indicating that Cd and Pb were bioavailable. Mercury concentrations were not significantly different among age groups. Cadmium concentrations in kidney and lung tissues of 9-10+ year old pigeons were similar to or exceeded concentrations of Cd reported in pigeons from another high traffic urban area and most wild avian species from Korea suggesting that Cd in this region of Beijing may be of concern. Homing pigeons provide valuable exposure and bioaccumulation data not readily available from air monitoring alone, thus providing information regarding potential health effects in wildlife and humans in urban areas. As environmental quality standards are implemented in China, homing pigeons will serve as a valuable bio-monitor of the efficacy of these actions.

The use of feathers of birds of prey as indicators of metal pollution

Published results concerning metal levels in feathers of birds of prey were listed and evaluated. Mercury concentrations have been studied most and the background values normally vary between 0.1 and 5 mg/kg dry weight the highest concentrations being in birds from aquatic food chains. Pollution causes elevated levels of mercury in feathers. The concentrations of cadmium, copper, lead and zinc show reasonable variation between species, areas and time periods. Feathers of birds of prey have proved to be good indicators of the status of environmental heavy metal pollution. Special attention should be paid to clean sampling and preparation of samples. Interpretation of the results requires knowledge on food habit, molting and migration patterns of the species. Several species representing different food chains should be included in comprehensive monitoring surveys. Chick feathers reflect most reliably local conditions.