Leaky doors: Private captivity as a prominent source of bird introductions in Australia

Returning to the Wilderness: Potential Habitat Suitability of Non-Native Pet Birds in South Africa

The global trade of non-native pet birds has increased in recent decades, and this has accelerated the introduction of invasive birds in the wild. This study employed ensemble species distribution modelling (eSDM) to assess potential habitat suitability and environmental predictor variables influencing the potential distribution of non-native pet bird species reported lost and sighted in South Africa. We used data and information on lost and found pet birds from previous studies to establish and describe scenarios of how pet birds may transition from captivity to the wild. Our study revealed that models fitted and performed well in predicting the suitability for African grey (Psittacus erithacus), Budgerigar (Melopsittacus undulatus), Cockatiel (Nymphicus hollandicus), Green-cheeked conure (Pyrrhura molinae), Monk parakeet (Myiopsitta monachus), and Rose-ringed parakeet (Psittacula krameri), with the mean weighted AUC and TSS values greater than 0.765. The predicted habitat suitability differed among species, with the suitability threshold indicating that between 61% and 87% of areas were predicted as suitable. Species with greater suitability included the African grey, Cockatiel, and Rose-ringed parakeet, which demonstrated significant overlap between their habitat suitability and reported lost cases. Human footprint, bioclimatic variables, and vegetation indices largely influenced predictive habitat suitability. The pathway scenario showed the key mechanisms driving the transition of pet birds from captivity to the wild, including the role of pet owners, animal rescues, adoption practices, and environmental suitability. Our study found that urban landscapes, which are heavily populated, are at high risk of potential invasion by pet birds. Thus, implementing a thorough surveillance survey is crucial for monitoring and evaluating the establishment potential of pet species not yet reported in the wild.

The wild cost of invasive feral animals worldwide

Invasive non-native species are a growing burden to economies worldwide. While domesticated animals (i.e. livestock, beasts of burden or pets) have enabled our ways of life and provide sustenance for countless individuals, they may cause substantial impacts when they escape or are released (i.e. become feral) and then become invasive with impacts. We used the InvaCost database to evaluate monetary impacts from species in the Domestic Animal Diversity Information System database. We found a total cost of $141.95 billion from only 18 invasive feral species. Invasive feral livestock incurred the highest costs at $90.03 billion, with pets contributing $50.93 billion and beasts of burden having much lower costs at $0.98 billion. Agriculture was the most affected sector at $80.79 billion, followed by the Environment ($43.44 billion), and Authorities-Stakeholders sectors ($5.52 billion). Damage costs comprised the majority ($124.94 billion), with management and mixed damage-management costs making up the rest ($9.62 and $7.38 billion, respectively). These economic impacts were observed globally, where Oceania, North America and Europe were the most impacted regions. Islands recorded a higher economic burden than continental areas, with livestock species dominating costs more on islands than mainlands compared to other feral species. The costs of invasive feral animals were on average twice higher than those of wild species. The management of invasive feral populations requires higher investment, updated regulations, and comprehensive risk assessments. These are especially complex when considering the potential conflicts arising from interventions with species that have close ties to humans. Effective communication to raise public awareness of the impacts of feral populations and appropriate legislation to prevent or control such invasive feral populations will substantially contribute to minimizing their socioeconomic and environmental impacts.

An Influx of Non-Native Bird Species into the Natural Environment Owing to the Accidental Release of Pet Birds in Japan

The escape of pet birds into the wild raises concerns about the introduction of invasive avian species. This study investigated the impact of escaped pet birds on the introduction of non-native species in Japan. Data sourced from four lost-and-found pet websites between January 2018 and December 2021 revealed 12,125 recorded escapes exhibiting both daily occurrences and seasonal fluctuations. Statistical modeling identified the monthly average temperature (positively correlated) and maximum electricity demand (negatively correlated) as influential factors. Text analysis revealed "window" and "open" as frequently cited reasons for escapes. Budgerigars (Melopsittacus undulatus) and Cockatiels (Nymphicus hollandicus) accounted for 76% of the total escape, suggesting a low perceived risk of establishment in nonnative environments. Interestingly, two globally established invasive species, the Rose-ringed Parakeet (Psittacula krameri) and Monk Parakeet (Myiopsitta monachus), were among the escaped birds. While the Rose-ringed Parakeet is locally naturalized in Tokyo and its adjacent prefectures, the Monk Parakeet failed to establish itself in Japan. Despite the limited number of escaped Monk Parakeets, ongoing efforts are crucial for preventing the potential re-establishment of species with such capabilities.

Patterns and Factors Influencing Parrot (Order: Psittaciformes) Success in Establishing Thriving Naturalized Populations within the Contiguous United States

Parrots (Order: Psittaciformes) represent one of the most striking and ecomorphologically diverse avian clades, spanning more than two orders of magnitude in body size with populations occupying six continents. The worldwide diaspora of parrots is largely due to the pet trade, driven by human desire for bright, colorful, and intelligent animals as companions. Some introduced species have aptly inserted themselves into the local ecosystem and established successful breeding colonies all around the globe. Notably, the United States is home to several thriving populations of introduced species including red-masked parakeets (Psittacara erythrogenys), monk parakeets (Myiopsitta monachus), nanday conures (Aratinga nenday), and red-crowned amazons (Amazona viridigenalis). Their incredible success globally begs the question as to how these birds adapt so readily to novel environments. In this commentary, we trace parrots through evolutionary history, contextualize existent naturalized parrot populations within the contiguous United States, and provide a phylogenetic regression analysis of body mass and brain size based on success in establishing breeding populations. The propensity for a parrot species to become established appears to be phylogenetically driven. Notably, parrots in the family Cacatuidae and Neotropical Pyrrhua appear to be poor at establishing themselves in the United States once released. Although brain size among Psittaciformes did not show a significant impact on successful breeding in the continental United States, we propose that the success of parrots can be attributed to their charismatic nature, significant intelligence relative to other avian lineages, and behavioral flexibility.

The effectiveness of citizen surveillance for detecting exotic vertebrates

Citizen observations of the natural world are increasing in detail, growing in volume and increasingly being shared on web-based platforms for the purpose of sharing information and/or the crowd-sourcing of species identification. From a biosecurity perspective, such citizen data streams are important as they are responsible for the majority of post-border reports and most detections of exotic pest species of concern. The sharing of sightings amongst what are effectively communities of practice is a key driver of having the sighting of an exotic pest species recognized and reported. Whilst it is clear that the eyes, ears, cameras, and microphones of citizens are a major component of biosecurity surveillance, it is unclear what level of surveillance this provides in the prospective sense. As an example, what confidence does citizen science provide about “proof of absence” for exotic pests of concern? The taxonomy of surveillance used within the field of biosecurity would classify such citizen activities as contributing to “general surveillance,” for which non-detections are typically not recorded and methods of quantitative analysis are still under development. We argue that while not recorded, there is considerable information about citizens activities that routinely underpins peoples mental inference about the level of surveillance provided by citizen activities. Furthermore, we show that it is possible to make such inference from general surveillance transparent by describing and characterizing the activities that potentially generate sightings in a way that is amenable to quantitative analysis. In the context of evaluating surveillance provided by citizens for incursions of exotic vertebrates, we provide examples of citizen observations providing early warning and hence preventing the establishment of species from a range of animal groups. Historically, analysis of the power of general surveillance has been restricted to being conceptual, based on qualitative arguments. We provide this, but also provide a quantitative model framework and provide examples of how different forms of general surveillance data may be analyzed, particularly in supporting inference of eradication/extinction.

Potential for invasion of traded birds under climate and land-cover change

Humans have moved species away from their native ranges since the Neolithic, but globalization accelerated the rate at which species are being moved. We fitted more than half million distribution models for 610 traded bird species on the CITES list to examine the separate and joint effects of global climate and land-cover change on their potential end-of-century distributions. We found that climate-induced suitability for modelled invasive species increases with latitude, because traded birds are mainly of tropical origin and much of the temperate region is 'tropicalizing.' Conversely, the tropics are becoming more arid, thus limiting the potential from cross-continental invasion by tropical species. This trend is compounded by forest loss around the tropics since most traded birds are forest dwellers. In contrast, net gains in forest area across the temperate region could compound climate change effects and increase the potential for colonization of low-latitude birds. Climate change has always led to regional redistributions of species, but the combination of human transportation, climate, and land-cover changes will likely accelerate the redistribution of species globally, increasing chances of alien species successfully invading non-native lands. Such process of biodiversity homogenization can lead to emergence of non-analogue communities with unknown environmental and socioeconomic consequences.

Wildlife trade and the establishment of invasive alien species in Indonesia: management, policy, and regulation of the commercial sale of songbirds

In Southeast Asia, mynas (genus Acridotheres) are amongst the most invasive bird species. Information is largely lacking as to where they have established themselves. The spread of invasive, non-native mynas is partially or largely driven by the massive trade in these species as songbirds. While preventing unintentional introductions early is the most effective management option, these species continue to be traded in bird markets throughout the region. We focus on the trade of native and non-native species of mynas, and the establishment of non-native mynas on the Indonesian islands of Java, Bali, and Lombok. Between 2016 and 2019, through field surveys and use of citizen science data (e.g., Burungnesia, iNaturalist, birding reports), we assessed where non-native mynas have been recorded in the wild on these three islands; through bird market surveys we established in which cities these birds are traded. We recorded common myna in Yogyakarta, one of our three survey areas. Combining all records, the areas where alien invasive mynas are established are Greater Jakarta (common and jungle myna), Yogyakarta (common myna), Bali (common and bank myna) and Lombok (common and Javan myna). Two-thirds of the records come from farmlands, home gardens and urbanised areas. In the bird markets, we recorded ~ 23,000 mynas of five species for sale, with Greater Jakarta, Bali and Lombok standing out as areas with high numbers of potentially invasive alien species offered for sale. Restrictions on the sale of wild-caught birds are not adhered to. Well-intended policies concerning the breeding and sale of legally protected species, whereby 10% of the stock is bred to be released in the wild, exacerbate the risk of the establishment of non-native species. We surmise that one of the most effective ways to reduce the risk of the accidental or deliberate release of potentially invasive alien mynas (and indeed other birds) into the wild is for governments and conservationists to work more closely with the retailers who hold the key to informing and educating consumers.

The Number and Distribution of Introduced and Naturalized Parrots

Parrots have been transported and traded by humans for at least the last 2000 years and this trade continues unabated today. This transport of species has involved the majority of recognized parrot species (300+ of 382 species). Inevitably, some alien species either escape captivity or are released and may establish breeding populations in the novel area. With respect to parrots, established but alien populations are becoming common in many parts of the world. In this review, we attempt to estimate the total number of parrot species introduced into the wild in non-native areas and assess how many of these have self-sustaining breeding populations. Based the public databases GAVIA, eBird, and iNaturalist, 166 species of Psittaciformes have been introduced (seen in the wild) into 120 countries or territories outside of the native range. Of these, 60 species are naturalized, and an additional 11 species are breeding in at least one country outside of their native range (86 countries or territories total). The Rose-ringed Parakeet (Psittacula krameri) and Monk Parakeet (Myiopsitta monachus) are the most widely distributed and successful of the introduced parrots, being naturalized in 47 and 26 countries or territories, respectively. Far and away, the United States and its territories support the greatest number of naturalized parrots, with 28 different species found in either the continental US, or Hawaii or Puerto Rico. Naturalized species as well as urbanized native species of parrots are likely to continue increasing in numbers and geographical range, and detailed studies are needed to both confirm species richness in each area as well mitigate potential ecological impacts and conflicts with humans.

The Role of the Songbird Trade as an Anthropogenic Vector in the Spread of Invasive Non-Native Mynas in Indonesia

The wildlife trade has facilitated the introduction of invasive non-native species, which may compete with native species for resources and alter ecosystems. Some of these species have great potential to become invasive if released or escaped from captivity. Here we studied the pet trade in a group of open countryside birds, the mynas (Acridotheres spp.) in Indonesia, and identified the areas that are at high risk of facing the establishment of these species. Mynas are among the most invasive birds in Southeast Asia. Once established in a new area, they are almost impossible to eradicate and can have strong negative impacts on the ecosystem. Preventing their introduction is therefore essential. Yet, invasive non-native mynas continue to be traded openly. We present data on the trade in seven species of mynas on Java, Bali and Lombok, with three species being native to parts of one or two of these islands, but not to the remainder, and four that are non-native to the region. From 2016 to 2021 we conducted 255 surveys of 30 animal markets. We recorded over 6000 mynas that were offered for sale outside their native range. Areas most at risk because of their high prevalence in specific animal markets, are Greater Jakarta, eastern Java, Bali and Lombok. The number of invasive non-native mynas recorded was positively related to the size of the animal market. Indonesia is signatory to several international agreements (CBD, ASEAN) that have policies and guidelines to prevent the introduction of invasive non-native species, but compliancy is weak. Annually hundreds and possibly thousands of invasive non-native mynas are released by Indonesian conservation authorities in regions that are outside their native range. Effective management of, and regulation of trade in, potential invasive non-native birds in Indonesia falls short and inadvertently greatly aids both their introduction and establishment.

Nuevas citas de los galápagos chinos Mauremys reevesii (Gray, 1831) y Mauremys sinensis (Gray, 1834) (Testudines, Geoemydidae) en España

El comercio de quelonios acuáticos como animales de compañía y su eventual liberación o escape ha conllevado la detección de especies exóticas naturalizadas o formando poblaciones invasoras en ecosistemas acuáticos. La importación de Mauremys spp. exóticos implica una nueva amenaza para la conservación de los ecosistemas acuáticos, debido a su capacidad de hibridarse con la especie nativa Mauremys leprosa. En este trabajo se documentan 16 nuevos registros de ejemplares asilvestrados de los galápagos asiáticos Mauremys reevesii y Mauremys sinensis en Andalucía (sur de España). La mayor parte de ellos (13) corresponden a ambientes acuáticos artificiales asociados a áreas urbanas y el resto se encontraron en espacios naturales protegidos con poblaciones naturales de M. leprosa. Estas nuevas citas ponen de manifiesto que los nuevos taxones comercializados reproducen el patrón de venta-abandono-naturalización-invasión ya acaecido con otras especies exóticas de galápagos. El número de ejemplares de Mauremys exóticos importados en España (más de 100.000 desde 2006) sugiere que el número real de ejemplares asilvestrados podría ser bastante mayor al documentado en los trabajos publicados.

Text classification to streamline online wildlife trade analyses

Automated monitoring of websites that trade wildlife is increasingly necessary to inform conservation and biosecurity efforts. However, e-commerce and wildlife trading websites can contain a vast number of advertisements, an unknown proportion of which may be irrelevant to researchers and practitioners. Given that many wildlife-trade advertisements have an unstructured text format, automated identification of relevant listings has not traditionally been possible, nor attempted. Other scientific disciplines have solved similar problems using machine learning and natural language processing models, such as text classifiers. Here, we test the ability of a suite of text classifiers to extract relevant advertisements from wildlife trade occurring on the Internet. We collected data from an Australian classifieds website where people can post advertisements of their pet birds (n = 16.5k advertisements). We found that text classifiers can predict, with a high degree of accuracy, which listings are relevant (ROC AUC ≥ 0.98, F1 score ≥ 0.77). Furthermore, in an attempt to answer the question ‘how much data is required to have an adequately performing model?’, we conducted a sensitivity analysis by simulating decreases in sample sizes to measure the subsequent change in model performance. From our sensitivity analysis, we found that text classifiers required a minimum sample size of 33% (c. 5.5k listings) to accurately identify relevant listings (for our dataset), providing a reference point for future applications of this sort. Our results suggest that text classification is a viable tool that can be applied to the online trade of wildlife to reduce time dedicated to data cleaning. However, the success of text classifiers will vary depending on the advertisements and websites, and will therefore be context dependent. Further work to integrate other machine learning tools, such as image classification, may provide better predictive abilities in the context of streamlining data processing for wildlife trade related online data.

Detection of Immunoreactivity to Psittaciform Bornavirus in the Serum of a Wild Cacatuid in Victoria, Australia

An indirect immunofluorescence serologic assay, PCR assay, and histopathology were used to screen for psittaciform orthobornaviruses (PaBV) in wild Cacatuidae in Victoria, Australia. Anti-PaBV antibodies were detected, but PCR and histopathology did not detect PaBV. This study presents the first evidence of PaBV in wild birds in Australia.

Amelioration of Pet Overpopulation and Abandonment Using Control of Breeding and Sale, and Compulsory Owner Liability Insurance

Simple Summary

Overpopulation and abandonment of pets are long-standing and burgeoning concerns that involve uncontrolled breeding and selling, illegal trafficking, overpopulation, and pet-safety and well-being issues. Historical and current prevention measures for avoiding these problems, such as sanctions, taxes, or responsibility education, have failed to provide significant moderation or resolution. Globally, millions of pets are commercially and privately bred and abandoned annually, damaging biodiversity and ecosystems, and presenting road safety and public health risks, in addition to becoming victims of hardship, abuse, and illegal trafficking, especially in the case of exotic species. This article proposes a novel comprehensive management system for amelioration of overpopulation and abandonment of pets by using greater control of supply and demand of the pet market, highlighting the role of the compulsory owner liability insurance to prevent pet abandonment and all its associated costs. This system aims to act preventatively, through flexible protocols within the proposed management system to be applied to any pet and any country.

Abstract

Overpopulation and abandonment of pets are long-standing and burgeoning concerns that involve uncontrolled breeding and selling, illegal trafficking, overpopulation, and pet safety and well-being issues. Abandonment of pets creates numerous negative externalities and multimillion-dollar costs, in addition to severe consequences and problems concerning animal welfare (e.g., starvation, untreated disease, climatic extremes, uncertainty of rescue and adoption), ecological (e.g., invasive species and introduction of novel pathogens), public health and safety (e.g., risks to people from bites, zoonoses, or road hazards), and economic (e.g., financial burdens for governmental and nongovernmental organizations). These interwoven problems persist for several reasons, including the following: (1) lack of an efficient system for the prevention of abandonment and overpopulation, (2) lack of regulatory liability for pet owners, (3) lack of legal alternative to abandonment. This article proposes a novel comprehensive management system for amelioration of overpopulation and abandonment of pets aimed to tackle the current supply and demand dysfunction of the pet market and provide a legal alternative to abandonment.

Pet or pest? Stable isotope methods for determining the provenance of an invasive alien species

The illegal pet trade facilitates the global dispersal of invasive alien species (IAS), providing opportunities for new pests to establish in novel recipient environments. Despite the increasing threat of IAS to the environment and economy, biosecurity efforts often lack suitable, scientifically-based methods to make effective management decisions, such as identifying an established IAS population from a single incursion event. We present a proof-of-concept for a new application of a stable isotope technique to identify wild and captive histories of an invasive pet species. Twelve red-eared slider turtles (Trachemys scripta elegans) from historic Australian incursions with putative wild, captive and unknown origins were analysed to: (1) present best-practice methods for stable isotope sampling of T. s. elegans incursions; (2) effectively discriminate between wild and captive groups using stable isotope ratios; and (3) present a framework to expand the methodology for use on other IAS species. A sampling method was developed to obtain carbon (δ13C) and nitrogen (δ15N) stable isotope ratios from the keratin layer of the carapace (shells), which are predominantly influenced by dietary material and trophic level respectively. Both δ13C and δ15N exhibited the potential to distinguish between the wild and captive origins of the samples. Power simulations demonstrated that isotope ratios were consistent across the carapace and a minimum of eight individuals were required to effectively discriminate wild and captive groups, reducing overall sampling costs. Statistical classification effectively separated captive and wild groups by δ15N (captive: δ15N‰ ≥ 9.7‰, minimum of 96% accuracy). This study outlines a practical and accessible method for detecting IAS incursions, to potentially provide biosecurity staff and decision-makers with the tools to quickly identify and manage future IAS incursions.

New aliens in Australia: 18 years of vertebrate interceptions

Abstract ContextAustralia has a high diversity of endemic vertebrate fauna. Yet, transnational human activities continue to increase the rate of transportation, introduction and establishment of new alien vertebrates in Australia, to the detriment of environmental and socioeconomic services. Eradication of invasive vertebrates is often costly and without guarantee of success; therefore, methods for detecting, intercepting and preventing the transport of alien species earlier in the invasion pathway provide substantial benefit. AimTo anticipate emergent threats to Australian biosecurity posed by the transport and introduction of new alien vertebrates over time. MethodsWe collated vertebrate interception data from various mainland Australian State, Territory and Commonwealth government reporting agencies, including data from a previously published study, at both pre-border and post-border stages from 1999 to 2016. Using generalised linear and generalised additive modelling, we predicted trends in interception frequency using predictors such as vertebrate taxa, detection category and alien status. Key resultsInterception frequency increased over time for all vertebrate classes, for pre-border stowaways and for post-border captive and at-large interceptions, with no saturation in the accumulation of new species over time. Five species were responsible for almost half of all incidents, of which red-eared sliders (Trachemys scripta elegans), boa constrictors (Boa constrictor) and corn snakes (Pantherophis guttatus) are prominent in Australia’s illegal alien pet trade. Rose-ringed parakeets (Psittacula krameri) are prominent in the legal alien cage-bird trade, which remains poorly regulated. Asian common toads (Duttaphrynus melanostictus) were frequently detected as stowaways, and most stowaway incidents originated from Southeast Asia, particularly Indonesia, via shipping. Data deficiency for pre-border incidents increased rapidly in 2015 and 2016. ConclusionsAustralia is subject to a persistent and increasing risk of alien vertebrate introductions and incursions over time, owing partly to emergent trends in the alien pet trade as well as increased global trade and tourism. ImplicationsThe future of Australia’s biosecurity remains dependent on stringent border security to prevent the arrival of novel species, but our findings also highlight the importance of ongoing management and control of high-risk species already present, often illegally, within Australia.

History of nonnative Monk Parakeets in Mexico

Nonnative Monk Parakeets have been reported in increasing numbers across many cities in Mexico, and were formally classified as an invasive species in Mexico in late 2016. However, there has not been a large-scale attempt to determine how international pet trade and national and international governmental regulations have played a part in colonization, and when the species appeared in different areas. We describe the changes in regulations that led the international pet trade market to shift to Mexico, then used international trade data to determine how many parakeets were commercially imported each year and where those individuals originated. We also quantified the recent increases in Monk Parakeet (Myiopsitta monachus) sightings in Mexico in both the scientific literature and in citizen science reports. We describe the timeline of increased reports to understand the history of nonnative Monk Parakeets in Mexico. As in other areas where the species has colonized, the main mode of transport is through the international pet trade. Over half a million Monk Parakeets were commercially imported to Mexico during 2000–2015, with the majority of importation (90%) occurring in 2008–2014, and almost all (98%) were imported from Uruguay. The earliest record of a free-flying Monk Parakeet was observed during 1994–1995 in Mexico City, but sightings of the parakeets did not become geographically widespread in either the scientific literature or citizen science databases until 2012–2015. By 2015, parakeets had been reported in 97 cities in Mexico. Mexico City has consistently seen steep increases in reporting since this species was first reported in Mexico. Here we find that both national and international legal regulations and health concerns drove a rise and fall in Monk Parakeet pet trade importations, shortly followed by widespread sightings of feral parakeets across Mexico. Further monitoring of introduced Monk Parakeet populations in Mexico is needed to understand the establishment, growth and spread of introduced populations.