Timing is of the Essence: Later Breeding Predicts Lower Survival in American Kestrels (Falco sparverius)

Organisms have evolved annual cycles so that energy-intensive life-history events coincide with peak food abundance. I used breeding season mark-recapture data from American kestrels to test the hypothesis of whether the mismatch between lay-date and the start-of-spring would predict adult survival. We also tested whether the timing of when a bird fledged relative to the onset of spring predicted hatch-year mortality. Preliminary results show that timing did predict apparent survival rates of both adult and hatch-year kestrels. Understanding the fitness of breeding phenology for a species will help us predict how that species could be affected by a changing climate.