December 6, 2022

The Wild Animal Initiative Grants Program has disbursed hundreds of thousands of dollars of research funding to high-impact projects with great potential to increase our understanding of wild animal lives. Earlier this year, we announced our first cohort of seven grantees, each with unique proposals on a diverse array of wild animal species. 

Now, we’re pleased to announce four additional projects we’re funding in 2022. Wild Animal Initiative asked each grantee to describe their project and share how their work will add to our knowledge of wild animal welfare. As a result of our grantees’ investigations, we’ll learn more about how gut microbiome, road noise, and other factors impact the well-being of wild animals. 

“It takes guts to grow in the city: the role of the gut microbiome in the welfare of juvenile urban birds”

Pablo Capilla-Lasheras, University of Glasgow, United Kingdom

Grant: $59,052

What is your project?

Pablo Capilla-Lasheras (PCL): Urban sprawl is changing the planet with unprecedented speed, pushing animals to the limits of their physiological capabilities. Among the novel stressors that wild animals face in cities, shifts in diet are prevalent and have negative consequences for welfare. Research clearly shows that juvenile birds in urban habitats have low-quality diets, causing stunted growth and increased early-life mortality. While high juvenile mortality may not impact the persistence of wild animal populations in cities, it represents a major source of juvenile suffering. 

In this project, I will study juvenile blue tits (Cyanistes caeruleus) and investigate how to improve their welfare in urban areas using an integrative approach that will combine metrics of animal welfare with the study of gut microbiomes. The gut microbiome is formed by symbiotic microorganisms, and several lines of evidence suggest that we can improve juvenile welfare through a better understanding of the link between poor-quality urban diets, gut microbiome composition, and welfare. My goal for this project is to understand the links among diet, gut microbiome health, and juvenile welfare in wild birds, as well as make recommendations to improve the life experience of juveniles growing in urban habitats.

What might gut microbiome have to do with welfare?

PCL: Diverse and rich communities of microorganisms live in the bodies of animals. Research has revealed that these host-associated communities play an important role in the health of their hosts. In particular, the community of microorganisms living in the gut (i.e., the gut microbiome) provides essential micronutrients, aids the digestion and assimilation of food by the host, and serves as a barrier against pathogenic microbes. The disruption of normal gut microbiome function has been associated with poor health in several species, including humans. 

What assessments of welfare do you plan to use?

PCL: I will assess the welfare of juvenile blue tits living in urban and non-urban habitats using a combination of behavioral and physiological markers. I will quantify food-begging behavior and sibling competition in the nest. Using very small blood samples, I will measure telomere length and telomere attrition rates, a biological marker commonly used to evaluate stress in wild animals.

How might this research lead to a better understanding of wild bird welfare?

PCL: Using data from field observations and data from a field experiment, I will investigate associations between the composition of the gut microbiome and the welfare of juvenile blue tits living in urban and non-urban habitats. The aim of this project is to better understand how gut microbiomes affect welfare and design strategies that could improve the welfare of wild animals by improving their gut microbiome.

“Development of novel measures of welfare in juvenile European starlings (Sturnus vulgaris) exposed to nutritional stress”

Melissa Bateson, Newcastle University, United Kingdom

Grant: $59,965

What is your project?

Melissa Bateson  (MB): Juvenile birds of the order Passeriformes such as the European starling experience massive mortality, much of which is caused by direct or indirect effects of nutritional stress. Of birds that survive, many will bear the “scars” of early-life stress that have consequences for their welfare. While some of this suffering is unavoidable, climate change and increases in urbanization, pollution, and intensive farming are increasing the stresses faced by young birds. There is potential for alleviating wild animal suffering in some of these situations, but ecologists need to know which birds are suffering most in order to focus interventions effectively. The aim of this project is to identify the metabolic fingerprint of nutritional stress in starling nestlings and to validate sensitive and noninvasive molecular biomarkers that can be used to assess the welfare of wild starlings.

Why is it important to find new ways to measure welfare in wild animals?

MB:  Most established welfare indicators involve either extensive behavioral measurements or samples of tissues that require catching animals and performing invasive procedures. We urgently need validated welfare indicators that can be measured easily and noninvasively in wild animals.

How could this research be applied to other species or groups of wild animals?

MB: Our project is about understanding the welfare consequences of early-life nutritional stress in European starlings. Nutritional stress is a common problem in juvenile wild animals of many species. In this project, we will identify novel biomarkers of exposure to nutritional stress in nestling starlings based on measuring thousands of small molecules. In many cases, these molecules will be found in other vertebrate species, too, meaning that our biomarkers will have the potential to translate to other species. We hope to develop methods for measuring the extent of a common problem that will be useful in a range of species.

How might the results of this study be used to help wild juvenile birds?

MB: The development of validated biomarkers of nutritional stress that can be noninvasively and cheaply measured in wild nestlings will open the door to large-scale monitoring of wild starling welfare in different environments. Such monitoring is necessary to establish the reasons for the decline in starling numbers and the associated welfare costs to surviving individuals.

“Determining the practical and statistical methods necessary for employing field-based metrics of welfare on wild juvenile birds”

Daniel Hanley, George Mason University, United States

Grant: $60,000

What is your project?

Daniel Hanley (DH): Wildlife conservation has traditionally focused on population-level metrics, which provide little information about the welfare of individual animals. However, recent work has proposed novel metrics of animal welfare that are an extension of population metrics. These methods provide a systematic approach for documenting the welfare of wild animals over early life. 

In this study, we will establish standardized field and analytical procedures necessary to estimate age-specific animal welfare in free-living juvenile prothonotary warblers (Protonotaria citrea) so that we may extend these welfare metrics to classic models of population ecology. We will investigate how specific physiological domains proportionately contribute to age-specific welfare estimates. Once established, quantitative welfare estimates such as welfare expectancy and elasticity of welfare expectancy can be applied widely. As a result, our study will facilitate the broader application of these welfare metrics, which will be instrumental in developing welfare-conscious conservation practices.

What are some challenges in assessing wild bird welfare?

DH: Unlike many other traits, an individual animal’s welfare is inherently challenging to assess. An organism’s affective state is not directly observable. Unlike in captive populations, the variables that we assume define good or poor welfare are often unmeasured in wild birds. The fact that wild birds are free to roam means they will encounter both rewarding and stressful experiences that we will never observe.

How do you plan to measure welfare in this study?

DH: Here we plan to measure welfare in juvenile prothonotary warblers, who nest in cavities. We will carefully document their early life experiences (e.g., feeding, within-nest competition). Then, we will quantify their stress levels across their early life by quantifying hormones from feathers they have developed over the nestling period. Our goal will be to use these data to calculate age-specific welfare estimates, which are crucial to determine the changes in welfare that an organism is likely to experience in their remaining years.

How might the results of this study help wild juvenile birds?

DH: Our results will document interindividual variability in welfare, while also quantifying how welfare changes across early life. We will establish an approach for determining the factors that contribute to age-specific welfare, which can be applied to other wild populations. Importantly, our quantitative approach will allow us to project welfare estimates into the future (age-classes or generations). Finally, our study will allow us to integrate new welfare metrics, such as welfare expectancy, into a rich set of population ecology models that will allow researchers to test a wide array of hypotheses. These advances will work in concert to more thoroughly document the needs and experiences of wild populations, and ultimately this should enable more effective stewardship of wild birds.

“The impact of road noise on the welfare of of free-living juvenile white-footed mice (Peromyscus leucopus)”

Michael Sheriff, University of Massachusetts Dartmouth, United States

Grant: $60,000

What is your project?

Michael Sheriff (MS): This project has two main goals. The first is to examine how road noise will influence the behavioral and physiological responses of juvenile small mammals to the risk of being eaten by predators. The second examines how noise may alter juvenile density and recruitment into areas of high and low predation risk. It will use a variety of field and lab-based techniques and span disciplines from ecology and animal behavior to physiology. We believe the outcomes of this project will not only inform our theoretical understanding of road noise effects but also contribute to applied conservation and management strategies to reduce the impact roads have on wildlife welfare.

What might road noise have to do with juvenile mouse welfare?

MS: Juvenile mice are at their most vulnerable stage of life, including in terms of being eaten by predators. They are dispersing from their natal range into new areas and need to select suitable areas to live. Road noise may increase their vulnerability during this phase of their lives by reducing their ability to detect predators and thus increasing the susceptibility to predation, and also, by reducing their ability to select appropriately suitable habitats to live. We have previously shown that road noise reduces adult mice responses to predation risk.

How could this study be adapted to other species or groups of animals?

MS: Given the ubiquity of roads, this study will be highly applicable to the impact of such noise on predator-prey interactions across taxa. 

In what ways might the results of this study be used to improve the lives of wild mice?

MS: In our study, we will record decibel noise levels at various distances from the road in addition to examining mouse responses at these locations. This will allow us to build a profile of noise impacts. We can then use this to provide noise mitigation recommendations to resource managers, conservation officers, and stakeholders. We hope such recommendations could improve and provide guidelines to road construction practices, particularly along protected areas.