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Full-Text Articles in Life Sciences

Costs And Benefits Of Variable Nest Density In Burrowing Owls: Effects On Predation, Ectoparasites, Egg Yolk Hormones, And Productivity, Justin Lamar Welty Aug 2010

Costs And Benefits Of Variable Nest Density In Burrowing Owls: Effects On Predation, Ectoparasites, Egg Yolk Hormones, And Productivity, Justin Lamar Welty

Boise State University Theses and Dissertations

Nesting density in birds is influenced by a number of factors including food availability, predation, and breeding site availability. As a result of a species’ nesting density, individuals incur certain costs and benefits related to predation rates, parasite levels, and productivity. I evaluated hypotheses related to these costs and benefits in burrowing owls (Athene cunicularia hypugaea) that nested within the Morley Nelson Snake River Birds of Prey National Conservation Area in southern Idaho. I calculated territory overlap, an index of nesting density, of actual nests by creating a 200m radius buffer around each nest and measuring the percentage …


Reproductive Failure And The Stress Response In American Kestrels Nesting Along A Human Disturbance Gradient, Erin Hennegan Strasser May 2010

Reproductive Failure And The Stress Response In American Kestrels Nesting Along A Human Disturbance Gradient, Erin Hennegan Strasser

Boise State University Theses and Dissertations

Human disturbance may be an influential environmental stressor that affects birds across life stages. I examined whether external and endogenous factors including habitat type, habitat quality and individual quality (hereafter quality), or human disturbance affect American Kestrel reproductive success in southwestern Idaho. Specifically, I was interested in how these factors lead to nest failure or abandonment. I also investigated whether elevated corticosterone (CORT) concentrations mediate the relationships among explanatory variables and nest failure. As nestling kestrels may respond to stressors differently from adults, I examined whether conditions experienced during the nestling stage affected nestling American Kestrel (Falco sparverius) hypothalamic pituitary …