June 29, 2023

Five more wild animal welfare projects received funding from Wild Animal Initiative’s Large Grants Program this spring. Since the inception of our Grants Program in 2021, we’ve disbursed more than $1.3 million cumulatively across 42 projects that focus on a range of topics related to wild animal welfare science, including density-dependent welfare and juvenile welfare. Our Grants Program funds academic research on high-priority questions in wild animal welfare, empowering researchers to explore topics neglected by other funders. 

We’re getting ready to announce our next call for proposals in the coming weeks — follow us on Twitter for the latest news. In the meantime, read more about the five projects we selected that explore how population density and social connections influence wild animal welfare. 

Empirical assessment of welfare in wild American mink and Eurasian otters: the effects of intra- and inter-specific population density 

PIs: Lauren Harrington, Oxford University; Maria Diez Leon, Royal Veterinary College; United Kingdom (UK)

Other grantees: Andrew Harrington and Andy Rothwell, field workers

Featured species: American mink (Neovison vison) and Eurasian otter (Lutra lutra)

Related fields: Community ecology; wildlife management 

Amount awarded: $162,257

Summary: This research seeks to understand the connection between population density and welfare in two species, American mink and Eurasian otter. Researchers will examine welfare effects of population density within the same species (intraspecific) and between the two species (interspecific). The researchers hypothesize that higher population density results in lower welfare for wild animals within these study systems. 

About American mink and Eurasian otters: In the UK, American mink are an introduced species, and Eurasian otters are a recovering species that has not yet recovered all of their former range. This allows researchers to compare welfare metrics of both species under various combinations of population density. There is extensive habitat and diet overlap between the two species and direct interspecific aggression, with otters typically outcompeting mink. 

How welfare will be measured: Primarily physiological indicators (hair samples to measure cortisol levels in mink and fecal samples to measure cortisol metabolites in otters), combined with behavioural (camera traps to assess exploratory/fearful behaviour indices, potentially other behavioural observations such as vocalisations) and physical indicators (body condition, ecto-parasite load) for a subsample of mink. 

Contributions to wild animal welfare science: This project will help increase our understanding of the conditions that might impact wild animal affective states and how these in turn might link to individuals’ responses to changes in density in their environments. 

Contributions to other species: By demonstrating the effects of population density on individual welfare, this research has the potential to apply across many taxa. It will provide a foundation and evidence base that can help address questions and inform the welfare assessment of other species subject to similar circumstances. 

Study sites: Various locations within the UK: Kent, multiple locations in Oxfordshire, Scottish Highlands, and Norfolk.  

Predicting density dependence of individual welfare in wild animal populations based on resource access linked to habitat availability and usage 

PI: Ross MacLeod, Liverpool John Moores University, UK

Featured species: House sparrow (Passer domesticus)

Related disciplines: Ecological modeling; population ecology; animal welfare science

Amount awarded: $159,744

Summary: Predictive population ecology modeling frameworks have great potential to provide understanding of the impacts of environmental stressors on population status and declines. This research plans to harness a successful modeling framework in population ecology known as Habitat To Population (HTP) and adapt it to study wild animal welfare. The researchers will modify the existing HTP framework to use thermal imaging measurements across populations to explain and predict welfare status and its change for local populations of wild animals. The existing study system is based on house sparrow colonies along urban-rural gradients in the UK. 

About house sparrows: House sparrows are sedentary (non-migrating), which makes them an ideal model species for this work. Each colony represents a distinct, local population and provides a wide range of population densities where the researchers can measure habitat availability and usage. House sparrows have high confidence around humans and are highly social. Entire colonies often flock together to visit feeding areas.

How welfare will be measured: Behavioral indicators (behaviors during feeding) and physiological indicators (body temperature).

Contributions to wild animal welfare science: Validating the HTP Welfare approach could help with the ability to predict wild animal welfare from observation and understanding of habitat selection patterns. The approach will allow the identification of quantifiable, evidence-based strategies for improving welfare. 

Contributions to other species: Results have the potential to improve our understanding of welfare in vast numbers of individual animals. Within birds, this approach would produce the data needed to explore the welfare impacts of density dependence and resource access impacting millions of individual wild animals. Beyond birds, the approach could be suitable for any taxa where habitat selection can be monitored. 

Study site: Urban-rural gradients in the UK.

Does population density influence the welfare of wild newts? 

PI: Luiza Figueiredo Passos, Liverpool John Moores University, UK

Other grantees: Chrysanthi Fergani, Liverpool John Moores University; Robert Young and Robert Jehle, University of Salford, UK

Featured species: Great crested newt (Triturus cristatus)

Related disciplines: Physiology; animal behavior

Amount awarded: $158,060

Summary: Research on European newts has indicated conditions that are optimal at the population level could result in suboptimal conditions at the individual level, potentially compromising welfare. For example, habitat suitability could increase recruitment, but greater population density has been associated with poor body condition and poor adult survivorship.  But welfare’s relationships with habitat suitability and abundance have not been investigated nearly as thoroughly, if at all. This research will examine how population density influences the welfare of wild great crested newts using the Five Domains model of animal welfare. 

About great crested newts: Great crested newts are pond-breeding amphibians with spatially structured populations. They are highly selective in their habitat requirements and will disperse over a maximum of about 1 km to find the appropriate pond. Their presence is an indicator of the health of a water source and general habitat quality.  

How welfare will be measured: Behavioral indicators (abnormal behavior; flight response; behavioral restriction), physiological indicators (body condition; corticosterone levels; telomere attrition; presence of morphological abnormalities), and affective indicators (calculation of anticipated mental state based on the four physical domains). 

Contributions to wild animal welfare science: This will be the first investigation of welfare in wild great crested newts and will explore how population density impacts individual welfare.

Contributions to other species: The knowledge gained from this project could potentially apply to other newts and pond-breeding species. The relationship between high density and resource competition leading to negative individual performance is not unique to newts and is common in many other species besides those which breed in ponds. 

Study site: Northern England, UK.

Social connections and their welfare implications in the wild

PI: Alex Thornton, University of Exeter, UK (Cornish Jackdaw Project)

Other grantees: Mike Mendl, University of Bristol, UK; PhD student to be selected

Featured species: Jackdaw (Corvus monedula)

Related disciplines: Animal cognition; animal behavior; ecology

Amount awarded: $157,962

Summary: Social connections in wild animals have yet to be considered from a welfare perspective. Until recently, researchers have lacked the ability to characterize social associations and welfare indicators at sufficient scale and detail under dynamic natural conditions. This project's established field sites contain thousands of Radio Frequency Identification (RFID)-tagged jackdaws, providing unprecedented opportunities to break new scientific ground and understand the associations between welfare and social connections. 

About jackdaws: Jackdaws provide an ideal study system because they are common in anthropogenic environments and highly sociable, and they form mixed-species flocks. Large numbers of individuals could benefit from the researchers’ findings. The study sites can produce big data on large numbers of known individuals: Automated feeders typically record around 100,000 visits from more than 2,000 jackdaws.

How welfare will be measured: Behavioral indicators (risk sensitivity; competitive success), physiological indicators (body temperature; sleep disturbances), and affective indicators (cognitive bias tests). 

Contributions to wild animal welfare science: Social connections are known to be crucial to subjective well-being in humans. This study will target one of the most likely determinants of well-being in social wild animals. Researchers will follow the Five Domains approach to provide some of the clearest evidence to date on the affective states and welfare of wild animals and their determinants. 

Contributions to other species: Findings are likely to relate to species that form social bonds (including some fish and mammals), occupy communal roosts subject to disturbance, breed colonially, or use welfare-related interventions such as feeding sites or nest boxes.

Study site: Cornwall, UK.

Density-dependent welfare in wild bird social systems: linking resource distributions with disease dynamics

PIs: Josh Firth, Oxford University, UK; Gregory Albery, Georgetown University, United States 

Featured species: Great tits (Parus major) and blue tits (Cyanistes caeruleus)

Related disciplines: Animal welfare science; animal behavior; community ecology; infectious disease; social networks

Amount awarded: $99,466

Summary: Population density affects many aspects of an individual’s health and welfare, and it’s likely that infectious disease is directly related to density. Despite this, it’s largely unknown how an individual’s experienced density causally shapes the risk and consequences of infection. The researchers will seek to address this knowledge gap using a long-term study of individually monitored wild birds, combining detailed monitoring data with novel experiments. This project will empirically determine how infectious disease shapes the relationship between population density and individual welfare, alongside considering the contributions of a wide range of intrinsic and extrinsic factors.

About great tits and blue tits: The Wytham Woods study site was established in the 1940s and is home to both great tits and blue tits. The RFID-tagged birds live in large social groups, making them ideal for studying how individuals are affected by population density.

How welfare will be measured: Behavioral indicators (nutrient intake; movement; social groups), physiological indicators (body condition; disease burden; parasite burden; weight), and fitness indicators (survival; reproduction).

Contributions to wild animal welfare science: This project will demonstrate how long-term studies of wild individuals can contribute to welfare science, and also provide rare experimental evidence of the causal effects of density on various measures of welfare. The use of RFID technology to experimentally manipulate foraging flocks will allow the researchers to gain detailed insights into how individuals are directly affected by changes in population density dynamics.

Contributions to other species: The Wytham bird study system has a long history of yielding broad insights in ecology and evolution that appear to be transferable across many species and populations. As the researchers draw on this population to study wild animal welfare, they believe this model system will provide fundamental answers to welfare-oriented questions that should be relatable across taxa. 

Study site: Wytham Woods, Oxford, UK.

These grants were made possible thanks to the generous support of Open Philanthropy.