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Burnham Fund 2020
Abstracts of winning applicants

Ed Drewitt

Peregrines eat a huge variety of prey as a generalist avian predator. During their population recovery in the UK over the past 40 years there have been huge changes in the populations of prey bird species in many habitats across the UK, particularly in farmland and woodlands. In this study I will examine what peregrines are eating in urban locations across the UK, how this varies over seasons and whether the diet has changed over time (20 years) in relation to the conservation status of its prey species. By recording the feathers, wings and other body parts of prey found on and below urban peregrine sites, the species and numbers of individuals of prey provide some insights into what urban-dwelling peregrines are eating. This research is the first detailed diet study in the UK that includes at least ten different locations and the longest running prey study (23 years) from one city. As peregrines are declining in parts of their UK-range, knowing what urban peregrines eat and how this has changed over time has important implications in understanding why peregrines may be increasing or stable in urban habitats, in contrast to their counterparts in parts of the countryside.   

J. Berton C. Harris, Joseph M. Kolowski, and Alan B. Williams

American Kestrels are familiar, charismatic raptors that are declining across the northeastern US. Loss and degradation of grassland habitats are likely important causes of the decline, but key research gaps limit our ability to draw conclusions. The advent of lightweight GPS transmitters presents an opportunity to refine our understanding of kestrel foraging habitat use and territory size. We propose to attach GPS transmitters to breeding kestrels in northern Virginia (three in pilot season, 20 overall). Our goal is to quantify time spent foraging in, and therefore relative importance of, four distinct categories of fields (cattle pastures, row-crop fields, hay fields, and native grasslands) to kestrels. We will also evaluate how territory size (which has only been estimated roughly for the species to date) is related to the habitat types found near the nest box, and how habitat use changes as the season progresses. This will be the first study to track kestrel movements at high resolution, and our results will reveal which kinds of fields are most productive and important for breeding kestrels. This information will be relevant to landowners and agencies in Virginia and across the northeastern United States, where the same four categories of fields dominate open areas.   

Andrea Gibbons

Cooperative breeding has been the focus of intense scrutiny for decades, but in raptor species the adaptive function of the behavior is unclear. Even in the highly-studied Harris’s Hawk, the behavior is poorly understood. To provide further insight into cooperative breeding in raptors, I will evaluate the behavior in south Texas Harris’s Hawks through the lens of direct and indirect benefits. I suggest that the direct benefits of group life, such as increased hunting capabilities, are likely to shape cooperative behaviors in Harris’s Hawks. If this is true, the level of relatedness between helpers and breeders will be less important than the benefits of group life and will result in both unrelated and related helpers. I would expect broods to include mixed paternity/maternity from unrelated helpers, although this would not preclude some young from delaying dispersal to gain direct group life benefits. Alternatively, if kin selection (indirect benefit) is the driving force of cooperation for Harris’s Hawks, delayed dispersing young will be the main source of helpers in cooperative groups and mixed parentage in broods will be rare. No other published study has used genetic methods to assess pairwise relatedness among Harris’s Hawks within cooperatively breeding groups and among nestlings.   

Robert Rosenfield

I propose to extend the long-term work on the breeding ecology and particularly the nesting phenology, of Peregrine Falcons in the central West Greenland study area near the town of Kangerlussuaq. Our work will well-complement the multi-decadal efforts begun in the 1970s by Drs. Bill Burnham and William Mattox, along with others, that dedicated much of their lives to document and provide conservation insights into Arctic biodiversity. We highlight that our research has been explicitly identified by the international Arctic Falcon Specialist Group as vital to the comprehensive assessment of circumpolar status of Peregrine Falcon populations and their and potential responses to recent climate change.