The wildcat (Felis s. silvestris) in the Mediterranean forest: sighting through photo-trapping and non-invasive hair collection for genetic purposes

The European wildcat (Felis silvestris silvestris) is a mesocarnivore species widely distributed in Europe, from Eastern Europe to Portugal and from Scotland to Italy. Recent biogeographical studies of wildcat populations have endeavoured to assess in detail the various issues that pose a threat to this species, including hybridization with domestic cats. The use of non-invasive sampling methods supported by photo-trapping and some attractants has made it possible to gather genetic material for the detection of native wildcats in locally threatened populations, some of which live in the Iberian Peninsula. Testimonies of naturalists, hunters and farm workers led our team to choose specific areas in two large territories of Mediterranean forests where the presence of wildcats has been historically attested: the Almonte River basin and the Sierra de San Pedro Mountains. Between 2014 and 2018, non-invasive hair sampling was performed using valerian (Valeriana officinalis) as an attractant and supported by photo-trapping to guarantee the collection of genuine biological material (hair samples). The hair samples were genetically assessed by sequencing the nuclear gene IRBP (interphotoreceptor retinoid-binding protein) and the mtDNA gene ND4 (NADH dehydrogenase subunit 4). Despite the low density of wildcats, this combined protocol proved to be an applicable tool for detecting the presence of elusive wildcats and other mesocarnivore species in this remote region of southern Europe. In addition, non-invasive hair trapping contributes to the collection of genetic material from current wildcat populations. This procedure could enhance future management actions focused on collecting quality individualized biological material.

An inside "beak": Molecular analysis of swab samples reveals the seabird diet of invasive Barn Owls in Hawai'i

Predation is an important species interaction to monitor when assessing an invasive species' impact on a particular ecosystem, but it can be difficult to observe and thus, fully understand. On Kaua'i island, invasive Barn Owls (Tyto alba) predate native seabirds, but difficult terrain in this region and the cryptic nature of owl predation make traditional monitoring of predation quite challenging. Using Barn Owls collected as part of removal efforts on Kaua'i and Lehua islands, we conducted DNA metabarcoding of owl digestive tracts to detect and determine seabird species they predate. We used a seabird-targeted 12s marker to sequence 112 swabs from 55 owls and detected 6 seabird taxa, including 2 ESA-listed seabirds-Hawaiian Petrel (Pterodroma sandwichensis) and Newell's Shearwater (Puffinus newelli), in 12 swabs from 11 owls (20% of sampled owls). Corresponding morphological assessment of owl stomach contents detected seabird species as prey items in only 2% (1/55) of sampled owls, highlighting the utility of molecular approaches for detecting diet items, especially degraded or visually absent items. Additionally, this approach has proven very useful in revealing cryptic trophic interactions in inaccessible seabird populations. For the most comprehensive analysis of diet, the use of both esophageal and cloacal swabs for metabarcoding is recommended. Supplementing metabarcoding with other methods that can provide complementary prey information, such as stable isotope analysis, would help to characterize trophic interactions more fully. The method described here has proven to be a reliable tool for investigating diet in invasive owls and may be used to investigate cryptic predation in living birds as a minimally invasive technique, as well.

Fox (Vulpes vulpes) involvement identified in a series of cat carcass mutilations

This study was designed to identify the cause of mutilation and death in 32 cats, part of a larger cohort found dead in Greater London, the United Kingdom, between 2016 and 2018. At the time, discussion in the media led to concerns of a human serial cat killer (dubbed The Croydon Cat Killer) pursuing domestic cats, causing a state of disquietude. Given the link between animal abuse and domestic violence, human intervention had to be ruled out. Using a combination of DNA testing, computed tomography imaging, and postmortem examination, no evidence was found to support any human involvement. Instead, a significant association between cat carcass mutilation and the presence of fox DNA was demonstrated. Gross examination identified shared characteristics including the pattern of mutilation, level of limb or vertebral disarticulation, wet fur, wound edges with shortened fur, and smooth or irregular contours, and marks in the skin, muscle, and bone consistent with damage from carnivore teeth. Together these findings supported the theory that the cause of mutilation was postmortem scavenging by red foxes (Vulpes vulpes). The probable cause of death was established in 26/32 (81%) carcasses: 10 were predated, 8 died from cardiorespiratory failure, 6 from blunt force trauma, one from ethylene glycol toxicity, and another from liver failure. In 6 carcasses a cause of death was not established due to autolysis and/or extensive mutilation. In summary, this study highlights the value of a multidisciplinary approach to fully investigate cases of suspected human-inflicted mutilation of animals.