physiology of seasonal interactions
Migratory animals complete their life history stages in various geographic locations, sometimes thousands of kilometers apart. Through these animals, these disparate locations are inextricably linked by seasonal interactions. For example, the quality of non-breeding habitat for migratory birds can influence migration timing and condition, ultimately carrying over to limit success on the breeding grounds. Beginning with my dissertation research, and continuing today, I have been interested in how seasonal interactions occur mechanistically within individual migratory birds. I have been examining: 1) how breeding and migration development can interact physiologically while birds are still on the wintering grounds, and 2) how winter habitat can influence body condition, breeding development, and signals important to sexual selection. For this work I have been working primarily on Parulid warblers on the wintering grounds in Jamaica, the breeding grounds in New Hampshire, and during migration in Chicago.
I have found that male American Redstart (Stophaga ruticilla) breeding preparation, as measured by testosterone production, begins while on the tropical wintering grounds and is positively related to body condition. Male redstarts with higher testosterone, from wetter winter habitats arrive earlier at breeding sites and ultimately are more likely to successfully breed. I have further demonstrated experimentally how testosterone can simultaneously stimulate breeding development and advance migration phenology. With Matt Reudink of Thompson Rivers University I have been experimentally examining how body condition, hormones, and winter habitat influence colorful plumage patches important to intraspecific interactions in redstarts. I am also collaborating with the Field Museum to compare the relative influence of endogenous (winter habitat wetness) and exogenous (distance to breeding site) factors on breeding development in birds that are killed by building collisions during spring migration in Chicago. This research has highlighted the importance of a full life-cycle approach when seeking to conserve migratory species, as population limitation occurs as a result of processes occurring in multiple locations.
I have found that male American Redstart (Stophaga ruticilla) breeding preparation, as measured by testosterone production, begins while on the tropical wintering grounds and is positively related to body condition. Male redstarts with higher testosterone, from wetter winter habitats arrive earlier at breeding sites and ultimately are more likely to successfully breed. I have further demonstrated experimentally how testosterone can simultaneously stimulate breeding development and advance migration phenology. With Matt Reudink of Thompson Rivers University I have been experimentally examining how body condition, hormones, and winter habitat influence colorful plumage patches important to intraspecific interactions in redstarts. I am also collaborating with the Field Museum to compare the relative influence of endogenous (winter habitat wetness) and exogenous (distance to breeding site) factors on breeding development in birds that are killed by building collisions during spring migration in Chicago. This research has highlighted the importance of a full life-cycle approach when seeking to conserve migratory species, as population limitation occurs as a result of processes occurring in multiple locations.
|
Relevant Publications
|
Collaborators
• Peter P. Marra, Smithsonian (PhD co-advisor, Post-doctoral advisor) • Rebecca L. Holberton, University of Maine (PhD co-advisor) • Frédéric Angelier, Centre d’Études Biologiques de Chizé • Matthew Reudink, Thompson Rivers University • Dave Willard, Field Museum 
|