PARENT SESSION
Contributed Oral Session 52: Avian Nesting and Breeding
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 524 A, Level 5, Palais des congrès de Montréal
How does food availability affect vulnerability to nest predation?
Duncan-Rastogi, Anne*,1, Zanette, Liana1, Clinchy, Michael1, 1 University of Western Ontario, London, Ontario, Canada
ABSTRACT- Food and predators are two of the most important factors limiting avian reproductive success. While food is generally thought to affect fecundity and predators nest predation, recent studies on birds have shown positive effects of food availability on nest predation rates. How food availability affects nest predation is unknown but most hypotheses propose that it is related to changes in adult and/or nestling behaviours such as nest guarding or begging. If these behaviours are important, then an untested assumption of the proposed hypotheses is that most predation is diurnal. We conducted a food supplementation experiment to test the role of food on nest predation rates, the timing of nest predation events, adult anti-predator behaviour and nestling begging behaviour. We found that song sparrows (Melospiza melodia) given extra food showed superior anti-predator behaviour at the nest and in turn, suffered much less diurnal nest predation than did unfed controls. Food supplemented incubating females were less conspicuous than females that were unfed because feeding led to long bouts on the nest, short bouts off the nest and few departures from the nest relative to control females. Nestling begging behaviour was equally conspicuous in food supplemented and control territories. Our results support the proposition that food availability does improve parental anti-predator behaviour and that these behaviours do in fact deter diurnal nest predation events.
Key words: food supplementation, nest predation, song sparrow, anti-predator behaviour