Population-level effects of wildlife rehabilitation and release vary with life-history strategy

Avian Haemosporidian Infection in Wildlife Rehabilitation Centres of Portugal: Causes, Consequences, and Genetic Diversity

In the last decade, over 40% of bird species in Europe have experienced poor and bad conservation status, with more than 30% of bird species in mainland Portugal threatened with extinction. Along with anthropogenic factors, parasites and pathogens such as avian haemosporidians have been suggested to be responsible for these avian population declines. Wildlife rehabilitation centres play an essential role in species conservation and preservation. Moreover, animals admitted for rehabilitation can provide valuable information regarding transmission and pathogenicity of many diseases that affect wild birds that are rarely sampled in nature. However, reports of haemosporidians in captive birds are still limited. Here, we explored the prevalence and genetic diversity of avian haemosporidians in 89 birds from 29 species admitted to rehabilitation centres in Portugal, showing an overall infection prevalence of 30.3%. The prevalence of infection was higher in Strigiformes and in birds admitted to rehabilitation centres due to debilitating diseases. Remarkably, 30% of the infected bird species have not been found to harbour malaria parasites in preceding studies. We detected 15 different haemosporidian lineages infecting a third of bird species sampled. Notably, 2 out of these 15 detected haemosporidian lineages have not been obtained previously in other studies. Furthermore, we also identified nine new host-parasite interactions representing new host records for these haemosporidian parasites. Finally, our results revealed that birds infected with haemosporidians require longer rehabilitation treatments, which increase the economic costs for rehabilitation and may impair their survival prospects. These findings emphasise the importance of integrating haemosporidian infection considerations into rehabilitation protocols, highlighting the challenges posed by these infections in avian conservation and rehabilitation, including economic and logistical demands.

Resistant Escherichia coli isolated from wild mammals from two rescue and rehabilitation centers in Costa Rica: characterization and public health relevance

This study aimed to characterize the antimicrobial resistance (AMR) and virulence profiles of 67 Escherichia coli isolates obtained from faecal samples of 77 wild mammals from 19 different species, admitted in two rescue and rehabilitation centers in Costa Rica. It was possible to classify 48% (n = 32) of the isolates as multidrug-resistant, and while the highest resistance levels were found towards commonly prescribed antimicrobials, resistance to fluoroquinolones and third generation cephalosporins were also observed. Isolates obtained from samples of rehabilitated animals or animals treated with antibiotics were found to have significantly higher AMR levels, with the former also having a significant association with a multidrug-resistance profile. Additionally, the isolates displayed the capacity to produce α-haemolysins (n = 64, 96%), biofilms (n = 51, 76%) and protease (n = 21, 31%). Our results showed that AMR might be a widespread phenomenon within Costa Rican wildlife and that both free-ranging and rehabilitated wild mammals are potential carriers of bacteria with important resistance and virulence profiles. These results highlight the need to study potential sources of resistance determinants to wildlife, and to determine if wild animals can disseminate resistant bacteria in the environment, potentially posing a significant threat to public health and hindering the implementation of a "One Health" approach.

Trends in Admissions and Outcomes at a British Wildlife Rehabilitation Centre over a Ten-Year Period (2012-2022)

Millions of animals pass through wildlife rehabilitation centres (WRCs) globally each year, some dying in captivity, others euthanised, and some released into the wild. Those caring for these animals are generally well-intentioned, but skills, knowledge, and resources may be limited, potentially compromising animal welfare. WRC databases provide an opportunity to provide an evidence base for treatment and conservation efforts. 42,841 records of animals admitted over a 10-year period to a British WRC were analysed. More birds (69.16%) were admitted than mammals (30.48%) and reptiles and amphibians (0.36%). Most admissions were in the summer (48.8%) and spring (26.0%) months. A total of 9 of the 196 species seen made up 57% of admissions, and hedgehogs were the most common species admitted (14% of all admissions and 20% of mammals). Juvenile animals (35.5%) were admitted more frequently than 'orphans' (26.0%) or adults (26.4%). 'Orphaned' was also the predominant reason for admission (28.3%), followed by 'injured' (25.5%). 42.6% of animals were eventually released back to the wild, 19.2% died in captivity, and 37.2% were euthanised; 1% of outcomes were unknown. The prognosis was better for orphaned animals than for those admitted because of injury. Unexpected natural deaths in captivity were found to decline over the period of study, consistent with improved early triage. These findings can be used to focus veterinary and WRC training and seasonal resources on the species and case types most likely to be successfully rehabilitated and released. The findings also have the potential to contribute to our understanding of anthropogenic impacts, historical and regional variations in ecosystem health, and resultant implications for animal welfare.

Interrupted Lives: Welfare Considerations in Wildlife Rehabilitation

Each year in the United States, thousands of sick, injured, or displaced wild animals are presented to individuals or organizations who have either a federal or state permit that allows them to care for these animals with the goal of releasing them back to the wild. The purpose of this review is to demonstrate the complexity of considerations rehabilitators and veterinarians face while trying to optimize the welfare of wild animals in need of care and rehabilitation. The process of rehabilitation is inherently stressful for wildlife. Maintaining an animal's welfare during the rehabilitation process-from initial contact and tria+ge to the animal's euthanasia, release, or captive placement-requires deliberate, timely and humane decision making. The welfare of wild animals can be improved by preventing human-related causes of admission, providing resources and support for wildlife rehabilitation (almost all rehabilitation in the United States is privately funded and access to veterinary care is often limited); further developing evidence-based wildlife rehabilitation methods and welfare measures, attracting more veterinary professionals to the field, harmonizing regulatory oversight with standards of care, training, and accountability, and increasing public education.

Outcomes for an arboreal folivore after rehabilitation and implications for management

Wildlife rehabilitation is a critical part of animal welfare that contributes to species conservation. Despite the resources that go into rehabilitation, how animals fare after release from care is unknown. This is particularly true for cryptic arboreal species where specialist diets in care and low detectability in the wild present challenges for both care and post-release monitoring. We evaluated post-release outcomes for koalas and assessed if koalas were fed appropriately while in care. We monitored 36 koalas that had experienced one of three categories of medical intervention (none, minor, major) during rehabilitation. We examined the drivers of (i) koala survival and (ii) movements post-release, and (iii) evaluated variation between the species of browse fed in care versus browse selected by koalas in-situ. Overall, the post release survival rate of koalas was 58.5%, with only koalas that received medical intervention experiencing mortality. A critical threshold for mortality occurred at two weeks post-release and mortality was related to the measurable indicators of low body condition and poor climbing ability at time of release. In the month following their release, animals translocated furthest from their capture point moved the furthest. There was poor overlap between the tree species that koalas were fed in care and those they utilized post-release. We provide recommendations to address critical gaps in rehabilitation practices, as well as priorities for monitoring animals post-release to improve outcomes for arboreal folivores.

Southern Sea Otter Rehabilitation: Lessons and Impacts from the Monterey Bay Aquarium

As biodiversity continues to decline across the globe, conservation of wildlife species and the ecosystems they inhabit is more important than ever. When species dwindle, ecosystems that depend on them are also impacted, often leading to a decrease in the life-giving services healthy ecosystems provide to humans, wildlife, and the global environment. Methods of wildlife conservation are complex and multi-faceted, ranging from education and advocacy to, research, restoration, and rehabilitation. Here, we review a conservation program focused on helping recover the federally listed threatened southern sea otter (Enhydra lutris nereis) population. We describe the development of unique rehabilitation methods and steps taken to advance the program’s conservation impact. Understanding this evolution can inform conservation efforts for other vulnerable species and their ecosystems.

Release and follow-up of a rehabilitated two-toed sloth (Choloepus hoffmanni) in a tropical dry forest in Ecuador

We present the first records of the post-release follow-up and monitoring of a rehabilitated two-toed sloth (Choloepus hoffmanni) as well as freezing behavior and an inferred antagonistic interaction for this species. Two-toed sloths are nocturnal and arboreal mammals whose survival relies on their capability to remain undetected by predators. Nevertheless, in the Guayas province of Ecuador, they are among the most common mammal species in rehabilitation centers. The liberation of animals back to the forest is the main goal of rehabilitation, while the follow-up of post-release human support of animals facilitates their re-establishment in their natural habitat. Follow-up, direct observation, and Bluetooth-based monitoring of the two-toed sloths secured the survival of this species in this part of Ecuador. The range of detectability of the device used indicates its suitability for tracking low-mobility animals. After the first five days, the number of trees used per day increased, and 19 trees within 1152 m2 were visited. Daylight and movement time range showed a correlation towards detectability. The follow-up effort allowed for keeping the two-toed sloth safe for 10 days after release. Due to the difficulty monitoring nocturnal animals, economic constraints in conservation, accessibility, and safety of the animals, biodegradable Bluetooth-based backpacks are recommended to ease the location of the animal and support its survival in the wild.

Revisiting the 4 R’s: Improving post-release outcomes for rescued mammalian wildlife by fostering behavioral competence during rehabilitation

Rescue, rehabilitation, and release (‘rescue-rehab-release’) of wildlife is an increasingly widespread practice across ecosystems, largely driven by habitat loss, wildlife exploitation and a changing climate. Despite this, its conservation value has not been realized, in part due to the scarcity of what has been termed “the 4th R”, research. Similar to conservation breeding and headstarting, rescue and rehabilitation entails close association of humans and the wildlife in their care over impressionable and extended periods. However, unlike these interventions, rescue and rehabilitation require an initial, and sometimes sustained, focus on crisis management and veterinary needs which can impede the development of natural behaviors and promote habituation to humans, both of which can compromise post-release survival and recruitment. In this perspective, we discuss the pathways toward, and implications of, behavioral incompetence and highlight opportunities for testable interventions to curtail negative outcomes post-release, without compromising the health or welfare of rescued individuals. We propose that practitioners ‘switch gears’ from triage to fostering behavioral competence as early in the rehabilitation process as is possible, and that research be implemented in order to develop an evidence-base for best practices that can be shared amongst practitioners. We focus on four mammalian species to illustrate specific contexts and considerations for fostering behavioral competence by building on research in the conservation translocation literature. Finally, we discuss a way forward that calls for greater cross-pollination among translocation scenarios involving extended time under human care during developmentally sensitive periods.