Pacific and Atlantic sea lion mortality caused by highly pathogenic Avian Influenza A(H5N1) in South America.

We describe the evolution of the outbreak of Highly Pathogenic Avian Influenza (HPAI) A(H5N1) in sea lions (Otaria flavescens) of South America. At least 24,000 sea lions died in Peru, Chile, Argentina, Uruguay, and Brazil between January-October 2023. The most plausible route of infection is cohabiting with or foraging on infected birds. However, we urge a detailed evaluation of the sea lions actual source of infection given that the concomitant massive wild bird mortalities registered in the Pacific Ocean did not occur in the Atlantic Ocean.

Recent Changes in Patterns of Mammal Infection with Highly Pathogenic Avian Influenza A(H5N1) Virus Worldwide.

We reviewed information about mammals naturally infected by highly pathogenic avian influenza A virus subtype H5N1 during 2 periods: the current panzootic (2020-2023) and previous waves of infection (2003-2019). In the current panzootic, 26 countries have reported >48 mammal species infected by H5N1 virus; in some cases, the virus has affected thousands of individual animals. The geographic area and the number of species affected by the current event are considerably larger than in previous waves of infection. The most plausible source of mammal infection in both periods appears to be close contact with infected birds, including their ingestion. Some studies, especially in the current panzootic, suggest that mammal-to-mammal transmission might be responsible for some infections; some mutations found could help this avian pathogen replicate in mammals. H5N1 virus may be changing and adapting to infect mammals. Continuous surveillance is essential to mitigate the risk for a global pandemic.

Evidence-based legislation, strong institutions and consensus needed to mitigate the negative impacts of free-ranging dogs.

Dogs bring many benefits to our society but, if not properly managed, they can be detrimental for humans, livestock and wildlife. We highlight the increasing problems associated with free-ranging dogs using examples from two regions of the world where this issue is pervasive, India and South America. In these regions, free-ranging dogs spread diseases, injure people, harm biodiversity, and negatively impact human livelihoods. We discuss why mitigating these deleterious effects can be extremely complicated because there are diverse challenges such as: (a) a lack of or inappropriate legislations concerning free-ranging dog management and human-dog interactions, (b) unregulated intentional and unintentional feeding of free-ranging dogs, (c) limitations of animal shelters, (d) non-responsible ownership, and (e) uncontrolled dog populations. As the management of animal species is usually shaped by differing interests, existing policies and regulations, views and social influence of stakeholders, power asymmetries between interested parties is yet another challenge in this regard. We need evidence-based legislations and strong institutions (e.g., public health and conservation institutions) that are capable of implementing governance principles and managing the complexities of this socio-ecological system by taking science-based decisions, and balancing power asymmetries to promote consensus.

Mass Mortality of Sea Lions Caused by Highly Pathogenic Avian Influenza A(H5N1) Virus.

We report a massive mortality of 5,224 sea lions (Otaria flavescens) in Peru that seemed to be associated with highly pathogenic avian influenza A(H5N1) virus infection. The transmission pathway may have been through the close contact of sea lions with infected wild birds. We recommend evaluating potential virus transmission among sea lions.

A 2200-year record of Andean Condor diet and nest site usage reflects natural and anthropogenic stressors.

Understanding how animals respond to large-scale environmental changes is difficult to achieve because monitoring data are rarely available for more than the past few decades, if at all. Here, we demonstrate how a variety of palaeoecological proxies (e.g. isotopes, geochemistry and DNA) from an Andean Condor (Vultur gryphus) guano deposit from Argentina can be used to explore breeding site fidelity and the impacts of environmental changes on avian behaviour. We found that condors used the nesting site since at least approximately 2200 years ago, with an approximately 1000-year nesting frequency slowdown from ca 1650 to 650 years before the present (yr BP). We provide evidence that the nesting slowdown coincided with a period of increased volcanic activity in the nearby Southern Volcanic Zone, which resulted in decreased availability of carrion and deterred scavenging birds. After returning to the nest site ca 650 yr BP, condor diet shifted from the carrion of native species and beached marine animals to the carrion of livestock (e.g. sheep and cattle) and exotic herbivores (e.g. red deer and European hare) introduced by European settlers. Currently, Andean Condors have elevated lead concentrations in their guano compared to the past, which is associated with human persecution linked to the shift in diet.

Lack of accessibility and clarity in regulations concerning dog access to protected areas lowers public awareness.

While natural protected areas are conceived for nature conservation, humans and their activities must also be considered. Conflict between the public and managers of protected areas can be minimized by regulations that clearly communicate which activities are allowed. Domestic dogs (Canis lupus familiaris) affect threatened species and impact numerous protected areas. In this study we evaluate: (1) the accessibility and clarity of regulations regarding dog access to protected areas in Argentina, (2) the public's knowledge of these regulations, (3) the public's expectations of the regulations (4) which institutions people consider should act when dog aggression occurs, and (5) measures suggested by people when dog aggression occurs. Poor accessibility and clarity of regulations were associated with poor public knowledge of them; there was also an association between visited protected areas that did not mention regulations and respondents who reported not knowing whether dogs were allowed or thinking dogs were allowed. In general, the respondents supported measures to regulate dog access to protected areas and the control of problematic dogs. We discuss several aspects that lead to a lack of clarity on dog regulations in protected areas and suggest approaches that could be used to overcome this conservation problem.

High incidence of plastic debris in Andean condors from remote areas: Evidence for marine-terrestrial trophic transfer.

Plastic pollution is an alarming environmental problem affecting diverse species worldwide. Scavenging birds are currently exposed to plastic due to contamination of their food sources. Here, we evaluated the ingestion of plastic by a threatened top scavenger, the Andean condor (Vultur gryphus), and the potential origin of the plastic. We analyzed the biotic (organic items from the diet) and abiotic (synthetic material) composition of regurgitated pellets in two remote areas of Peru associated with protected areas: a marine-coastal region and an Andean region. Condors consume mainly Pinnipeds and South American camelids in the marine-coastal region, and camelids and livestock in the Andean region. We found different sizes and varieties of plastic debris, with a very high frequency of occurrence (85-100%) of microplastics in pellets of both areas studied. The occurrence of microplastics differed between sites; although very high in general, the rate of occurrence and density were higher in the marine-coastal region. We also confirmed that carcasses consumed by condors in both study areas were contaminated with plastic. Therefore, plastic in Andean condors is most probably acquired through the food web in both the marine and terrestrial environments. Andean condors from Peru are highly contaminated with plastic, which may affect their health, population dynamics, and conservation. Moreover, as condors are apex scavengers, our results highlight the fact that plastic pollution in remote areas of Peru is present at different levels of the food web and in the environment. Urgent Action should be taken to reduce environmental contamination with this hazardous pollutant.

Risk effects cascade up to an obligate scavenger.

The effects of predation risk on prey populations have been studied extensively; yet, how risk is manifested in a trophically linked guild-scavengers-has been overlooked. Risk could be particularly consequential for obligate scavengers that are vulnerable while foraging and rely on carrion provisioned by, and shared with, apex predators. We investigated whether Andean condors (Vultur gryphus) respond to predation risk in a landscape where the main source of carrion are camelids killed by pumas (Puma concolor). We hypothesized that condors would exhibit different behavioral responses to predation risk while they search, encounter, and exploit carrion. We explored condor habitat selection while flying by tracking nine birds with satellite transmitters and monitored via camera traps 41 natural carcasses and 25 experimental carrion stations. We found that condors searched for carrion in areas with a high probability of occurrence of puma kills. However, condors avoided exploiting carrion in areas featuring tall vegetation and steep slopes-selected by pumas to stalk prey-suggesting that condors manage risk primarily through the identification of safe foraging sites prior to landing. Our finding that condors avoided foraging near stalking cover for pumas highlights the importance of risk effects beyond predator-prey interactions, particularly for obligate scavengers.

Cascading effects of a disease outbreak in a remote protected area.

Disease outbreaks induced by humans increasingly threaten wildlife communities worldwide. Like predators, pathogens can be key top-down forces in ecosystems, initiating trophic cascades that may alter food webs. An outbreak of mange in a remote Andean protected area caused a dramatic population decline in a mammalian herbivore (the vicuña), creating conditions to test the cascading effects of disease on the ecological community. By comparing a suite of ecological measurements to pre-disease baseline records, we demonstrate that mange restructured tightly linked trophic interactions previously driven by a mammalian predator (the puma). Following the mange outbreak, scavenger (Andean condor) occurrence in the ecosystem declined sharply and plant biomass and cover increased dramatically in predation refuges where herbivory was historically concentrated. The evidence shows that a disease-induced trophic cascade, mediated by vicuña density, could supplant the predator-induced trophic cascade, mediated by vicuña behaviour, thereby transforming the Andean ecosystem.

Veterinary pharmaceuticals as a threat to endangered taxa: Mitigation action for vulture conservation.

Overuse and misapplication of veterinary pharmaceuticals affect the ecosystem, even at low concentrations. Vultures are mainly exposed to these compounds when feeding on improperly disposed carcasses from animals treated before death. This produces diverse negative impacts on vulture health and populations, even leading to death. Using the available bibliography we determined which veterinary pharmaceuticals vultures are exposed to worldwide and assessed the potential consequences for these species. Based on the responsibilities of the different stakeholders, we also propose action to mitigate this problem. Of 104 articles addressing vulture exposure to veterinary pharmaceuticals, most came from Asia, Europe and Africa; almost no information was available on the Americas. Vultures were reported as being exposed to non-steroidal anti-inflammatory drugs (NSAIDs), antibiotics, anti-parasitic and euthanizing agents. Most available information is related to the catastrophic effect of the NSAID diclofenac in South Asia. Vultures are particularly exposed to veterinary drugs when ingesting carcasses from intensive livestock production, but other potential pathways (e.g., discards from salmon farms or fisheries) have not yet been properly evaluated. It is essential to improve scientific information on this topic - increasing the range of drugs and geographical areas studied - in order to implement sustainable conservation action for these birds. A combination of strategies could prove effective in reducing the impact of pharmaceuticals on the environment and non-target species. To mitigate this conservation problem, a set of multilateral actions should therefore be implemented, involving diverse stakeholders such as government representatives, pharmaceutical companies, veterinary practitioners, scientists and conservation agents, and local communities.

Flying wildlife may mask the loss of ecological functions due to terrestrial habitat fragmentation.

Land use change alters wildlife critical animal behaviours such as movement, becoming the main driver threatening wildlife ecological functions (WEF) and nature's contribution to people (NCP) provided by terrestrial species. Despite the negative impacts of current rates of terrestrial fragmentation on WEF, many ecological processes can be still occurring through aerial habitats. Here, we propose and discuss that the movement capabilities of aerial species, as well their functional redundancy with non-flying wildlife, are the mechanisms by which some ecological processes can be still occurring. We show examples of how the movements of aerial wildlife may be masking the loss of important functions and contributions by compensating for the lost ecosystem functions previously provided by terrestrial wildlife. We also highlight the implications of losing aerial wildlife in areas where that functional redundancy was already lost due to the impacts of land use change on terrestrial wildlife. We suggest to consider flying wildlife as a biological insurance against the loss of WEF and NCP due to terrestrial fragmentation and proposed some aeroconservation measures.

Functional traits driving species role in the structure of terrestrial vertebrate scavenger networks.

Species assemblages often have a non-random nested organization, which in vertebrate scavenger (carrion-consuming) assemblages is thought to be driven by facilitation in competitive environments. However, not all scavenger species play the same role in maintaining assemblage structure, as some species are obligate scavengers (i.e., vultures) and others are facultative, scavenging opportunistically. We used a database with 177 vertebrate scavenger species from 53 assemblages in 22 countries across five continents to identify which functional traits of scavenger species are key to maintaining the scavenging network structure. We used network analyses to relate ten traits hypothesized to affect assemblage structure with the "role" of each species in the scavenging assemblage in which it appeared. We characterized the role of a species in terms of both the proportion of monitored carcasses on which that species scavenged, or scavenging breadth (i.e., the species "normalized degree"), and the role of that species in the nested structure of the assemblage (i.e., the species "paired nested degree"), therefore identifying possible facilitative interactions among species. We found that species with high olfactory acuity, social foragers, and obligate scavengers had the widest scavenging breadth. We also found that social foragers had a large paired nested degree in scavenger assemblages, probably because their presence is easier to detect by other species to signal carcass occurrence. Our study highlights differences in the functional roles of scavenger species and can be used to identify key species for targeted conservation to maintain the ecological function of scavenger assemblages.

Limited sexual segregation in a dimorphic avian scavenger, the Andean condor.

Sexual segregation is widely reported among sexually dimorphic species and generally attributed to intraspecific competition. Prey diversity and human activities can reinforce niche segregation by increasing resource heterogeneity. Here, we explored trophic and spatial sexual segregation in the only avian scavenger that exhibits pronounced sexual size dimorphism (up to 50% difference in body mass) and a highly despotic social system, the Andean condor (Vultur gryphus). We predicted that larger and dominant males would exclude smaller and subordinate females from high-quality resources, leading to sexual segregation particularly in human-dominated landscapes showing increased prey diversity. We compared resource use between females and males across six sites in Argentina featuring a range of prey diversity via stable isotopes analysis of molted feathers (n = 141 individuals). We then focused on two sites featuring contrasting levels of prey diversity and quantified assimilated diet via stable isotopes and space use via GPS monitoring (n = 23 and 12 tagged individuals). We found no clear differences in isotopic niche space, individual variation in isotopic signature, or assimilated diet between females and males. However, there were differences in foraging locations between sexes, with females apparently using areas of fewer food resources more frequently than males. Local conditions defined the dynamics of fine-scale sexual differences in foraging sites; yet, unpredictable and ephemeral carrion resources likely prevent segregation by sexes at the landscape scale. Our study highlights complex dynamics of sexual segregation in vultures and the relevancy of analyses under multiple spatial-temporal scales to explore segregation in social species.

Global Aerial Habitat Conservation Post-COVID-19 Anthropause.

Aerial habitat is increasingly threatened. The coronavirus disease 2019 (COVID-19) anthropause shows that a decrease in human mobility and goods production for even a short period reduces the global anthropogenic impact on airspace fragmentation and pollution. Economic and environmental post-COVID-19 agendas should consider the changes observed in the aerial habitat during the anthropause.

Plastic ingestion and dispersion by vultures may produce plastic islands in natural areas.

Rubbish dumps can become an important environmental source of plastic. Several species feed on organic waste from these sites, but at the same time are exposed to non-organic materials. Species that can gather food in these sites might at the same time disperse waste consumed, but this has rarely been evaluated. We compare the occurrence of plastic debris in regurgitated pellets of three sympatric vultures from northwest Patagonia, Andean condors (Vultur gryphus), black vultures (Coragyps atratus) and turkey vultures (Cathartes aura), foraging in different degrees of humanized sites. We also evaluate the influence of rubbish dumps in the presence of plastic debris in pellets of the studied species and their potential role in spreading plastic to the environment. Most synthetic material present in pellets was plastic. Pellets of Andean condors, which avoid disturbed anthropic sites in this area, showed almost no plastic debris compared with the other sympatric vulture species, suggesting an influence of the foraging habits on plastic ingestion. For black and turkey vultures, we found that rubbish dumps may be an important source of plastic. The occurrence of plastic debris in pellets of black vultures sampled in 2010 and 2020 increased, probably associated with the increase in urbanization and waste production in the study area. Avian scavengers were exposed to and are able to transport plastic to distant communal roosts generating "plastic islands". It is necessary to reduce plastic generation and better waste management practices to avoid species and environments to be affected by this pollutant.