July 26, 2024

This summer, we selected six research projects as recipients of our Challenge Grants, which are awarded to large projects addressing critical research questions in wild animal welfare science. In our latest round of grants, we’re supporting projects in two research areas that are not often funded elsewhere: the validation of indicators of affective valence, and the welfare impacts of parasites and pathogens.

We’ve selected the following projects for this year’s Challenge Grants based on their potential to deepen our understanding of the concepts, methods, and interventions that will most rapidly accelerate progress in the field of wild animal welfare science.

Multiple projects involve the use of cognitive judgment bias tests. In these tests, animals are presented with ambiguous stimuli; their optimistic or pessimistic responses to these stimuli are then used as an indicator of their affective state or welfare. Cognitive bias tests are widely considered a reliable indicator of welfare, but they are challenging to implement for wild animals because they normally require the animals to undergo an initial training stage (Mendl et al. 2009). By supporting the development and validation of cognitive bias tests designed to be applied in the wild, we hope the field will not only benefit from the tests themselves, but also that expanded cognitive bias testing will accelerate the validation other behavioral or physiological markers by correlating them with the results of cognitive bias tests that may directly reflect the valence of affective states.

Indicator validation

To correctly understand wild animal welfare, indicators of welfare must be properly validated by directly examining their relationship to valence (the quality of feelings that animals experience). By validating indicators of affective valence, these three projects have the potential to help future researchers more easily assess changes in valence.

Field tests of bee welfare

Vivek Nityananda, Newcastle University, United Kingdom
$194,317

The goal of this project is to develop a cognitive judgment bias test for wild bees and pilot its use in the field. The project will investigate how bee cognitive biases and reward responses vary with factors expected to cause high or low welfare, such as light and vehicular pollution. The researchers will also develop an assay for assessing welfare based on individual variation in the bees’ consumption.

Why we funded this project
We are generally excited to support this project because it focuses on a wild insect. Insects are extremely abundant and their welfare is typically neglected. Validating a cognitive judgment bias test that can be implemented in the field for a wild insect would be a powerful step forward.

Validating the use of cognitive bias to assess affective valence in wild bird populations

Oliver Burman, University of Lincoln, United Kingdom
$193,684

The goal of this project is to develop and validate a cognitive bias test for assessing the welfare of woodland birds that does not require any training stage, and instead takes advantage of innate attraction and aversion to stimuli that resemble preferred or noxious prey (with a range of likeness accuracy, based on the principle of imperfect Batesian mimicry). Continuing the theme of exploiting natural variation, the project will use spatial variation in numerous components of habitat preferability that can be assumed to directionally affect welfare — such as food abundance and shelter — as natural experiments to validate their cognitive bias tests.

Why we funded this project
This project’s results are intended to be generalizable to numerous woodland bird species (e.g., tits, wrens, starlings). We also appreciate its creatively humane approach to validation, using innate preferences and natural variation in affective valence, rather than training and experimental manipulation. Plus, the project considers both presumably positive (e.g., food, shelter) and presumably negative (e.g., predator abundance) welfare factors, which further strengthens the validation.

Developing an automated cognitive bias task for wild squirrels

Vikki Neville, University of Bristol; Lisa Leaver, University of Exeter; United Kingdom
$157,049

The goal of this project is to develop a cognitive judgment bias test for use in wild gray squirrels that capitalizes on their innate behavior, avoiding the need for the extensive type of training that is usually part of cognitive judgment bias tests in captive settings. By making use of the widely available Raspberry Pi platform, the test should be relatively easy for other researchers to replicate and adapt for use in other species. To validate the test itself, the research team will also assess how measurement of cognitive judgment bias varies with factors assumed to affect the valence of animals participating in the test, such as distance from cover and levels of food provisioning in the environment, as well as how the test results correlate with other potential non-invasive behavioral and physiological indicators of welfare, such as the distance at which a squirrel flees from approaching humans, hair cortisol concentration, and real-time fluctuations in eye temperature in response to stimuli during the the test.

Why we funded this project
As noted above, cognitive bias tests are generally considered to be exceptionally robust welfare indicators, while gray squirrels are an abundant species and a prime target for near-term interventions. Therefore, we are excited to support the development of a cognitive judgment bias test for use on free-living gray squirrels, which will also help to assess the validity of simpler indicators, such as eye temperature and flight initiation distance.

Parasites and pathogens

Parasites are incredibly common in the wild (Chrétien et al. 2022), but we know very little about the total welfare effects they have on their hosts. These three projects have the potential to advance our knowledge about the impacts of parasites and pathogens on wild animal welfare.

Parasites in the city: How is the impact of parasites on wild animal welfare affected by urbanization?

Amanda Trask, Institute of Zoology, Zoological Society of London, United Kingdom
$199,941

This project will evaluate the extent to which parasitism and urbanization impact wild animal welfare, both independently and synergistically, using physiological data on the internal and external parasite loads of deceased gray squirrels, as well as their body condition, immune function, and stress response. The researchers will also collect behavioral welfare indicators from other squirrels using camera traps. This data will be collected along a gradient of urbanization levels and analyzed in the context of the squirrels’ sex and age, to compare population-level welfare across sites varying in degree of urbanization and average parasite metrics and predict how future increases in urbanization might impact wildlife welfare.

Why we funded this project
Gray squirrels are abundant, they live in close proximity to humans, and they could benefit from welfare interventions such as wildlife fertility control in the near future. Gray squirrels are not native in the UK, where this study will be conducted, and the welfare of non-native species is generally understudied or undervalued compared with native species of conservation interest. This project provides a special opportunity to take advantage of data from squirrels who are being killed as part of a government program, and to access valuable metrics that are hard to measure non-invasively, thereby creating from their deaths an opportunity to gain valuable insights that could ultimately help other squirrels. In addition to their good range of welfare indicators, we appreciate that this project will consider sex- and age-specific variation in welfare impacts and attempt to estimate “welfare expectancy” at a population level.

Does diet mediate effects of sublethal parasitic infections on host welfare?

Amanda Koltz, University of Texas at Austin, United States
$167,237

This project will test how infection by parasitic worms (helminths) influences host welfare in white-footed deer mice by evaluating the relationship between parasite burden and host body condition, microbiome, and stress physiology, as well as behaviors associated with anxiety (negative welfare) and exploration (positive welfare). The researchers will experimentally manipulate parasite burden by intervening to apply anti-parasitic medication (Ivermectin) as a treatment for some mice who were already infected with helminths.

Why we funded this project
We are excited to fund a study on wild mice, a highly numerous and neglected group, and especially one with such a welfare-friendly experimental approach — curing parasitic infections rather than causing them. The project also uses a holistic suite of physiological and behavioral indicators that should allow the researchers to disentangle overall welfare from narrow, mechanistic impacts of infection on the health and nutrition domains.

Are we making urban wildlife sick?

Carl Soulsbury, University of Lincoln, United Kingdom
$148,741

The goal of this project is to test whether differences in welfare among individual red foxes and individual European hedgehogs are explained by specific environmental stressors arising from urbanization (e.g., increased human population density, noise pollution, or reduced habitat heterogeneity). Notably, on a population level, foxes appear to have fared well alongside humans, while hedgehogs have struggled to cope with urbanization. The study will confirm whether this contrast is also seen at the level of individual welfare, and offers a unique opportunity to identify common environmental stressors that may be impacting the health and welfare of urban wildlife more generally. To assess welfare, the project will perform cognitive judgment bias and novel object tests and combine them with non-invasive indicators of physiological stress (fecal glucocorticoids and eye/ear temperature) and health (pathogen load).

Why we funded this project
We appreciate that this project considers specific characteristics of urban environments, as opposed to simply comparing urban environments with rural ones. This way, it has more potential to inform near-term interventions. Plus, the project design humanely allows for animals’ voluntary participation. In addition to using an effective suite of welfare indicators to investigate the impact of different parasite loads on welfare, the combination of cognitive bias testing with non-invasive physiological stress metrics will provide information on the validity of those metrics, which are being used concurrently in other projects.

Learn more about our grants program and browse other projects we’ve funded.