Migration Ecology of Sharp-shinned Hawks & Merlins
Project Lead: Ryan Bourbour
Falcons and Accipiters use powered flight during migration and must hunt in order to fuel their journey. Both Sharp-shinned Hawks (Accipiter striatus) and Merlins (Falco columbarius) have a diet dominated by passerines, and are thought to track flocks of migrating songbirds during migration. Determining the diet of migrating raptors has been difficult in the past, however, by utilizing modern genetic techiniques we can uncover the specific diet of these two predators during their fall migration. We aim to develop a novel dietary study technique that not only has the potential to reveal ecological interactions within migratory flyways, but also opens up opportunities to safely and non-invasively study the diet of enigmatic raptor species around the world.
Genetics and Genomics
Population Genetics of Cooper's Hawks
Project Lead: Breanna Martinico
Cooper’s Hawks (Accipiter cooperii) are secretive woodland raptors that breed in the United States, southern Canada, and central Mexico. Cooper’s Hawks are conspicuous visitors at hawk migration sites in fall, and it is understood that individuals essentially return to the same locality to breed in subsequent years, which perpetuates genetic differences between populations.Though morphological and behavioral differences have been documented across the species’ geographic range, there are currently no recognized subspecies of the Cooper’s Hawk. Studying genetic diversity and population structure of the species will help us understand the genetic variability present, which is important for a species to survive over evolutionary time and in the face of anthropogenic changes to the environment. We will collect genetic samples from Cooper’s Hawks banded at established hawk banding sites and from individuals presented to rehabilitation facilities to quantify the genetic diversity and structure of populations throughout the breeding range of the species.
Adaptation and Diversification of the Galápagos Hawk
Project Lead: Emily Abernathy
While recent technological advances have made studying the mechanisms behind speciation and adaptation more feasible, empirical studies in natural populations are lacking. The Galápagos hawk (Buteo galapagoensis) is thought to be undergoing active speciation and is therefore an ideal system to study adaptive evolution. The Galápagos hawk and its most recent ancestor show large variations in morphology despite diverging only 126,000 years ago. We are using next-generation sequencing to study the mechanisms behind the divergence of the Galápagos hawk by using restriction associated DNA sequencing (RADseq) to 1) resolve the phylogenetic relationship between the Galápagos hawk and its most recent ancestor and 2) locate regions of the genome associated with local adaptation and rapid morphological change. This study will advance our understanding of the roles of neutral and adaptive evolution while providing insight into the interplay of evolutionary forces that lead to the formation of new species.
Merlin Population Genetics and Phylogeography
Project Lead: Breanna Martinico
We are currently investigating the patterns of morphological and genetic differentiation across the North American range of Merlin (Falco columbarius) in relation to contemporary anthropogenic factors and historic impacts (Pleistocene glaciation). In the mid-20th century, many raptor species experienced population declines due to the widespread use of the pesticide DDT, an organochlorine compound with long-lived metabolites. Currently, little is known about the genetic impacts on many species that faced population bottlenecks in the DDT-era but received little conservation attention, such as Merlin in North America. We are investigating the genetic impacts of the DDT-era population bottleneck and the impacts on population structure associated with historic Pleistocene glaciation in North American Merlins.
Additionally, the three North American Merlin subspecies (F. c. suckleyi, columbarius, and richardsonii) are described to have different plumage characteristics and distinct ranges. F. c. suckleyi is found in the Pacific northwest and southeastern Alaska and has the darkest plumage of the three subspecies. F. c. columbarius is paler than F. c. suckleyi and found from Newfoundland to Alaska. F. c. richardsonii is the palest of the three subspecies and breeding in central Canada and the north central portion of the United States. However, the true environmental and/or genetic mechanism(s) responsible for maintenance of plumage variation in North American Merlin are yet to be discovered.