AVIS-IBIS

Birds of Indian Subcontinent

Food Supply and the Occurrence of Brood Reduction in Swainson's Hawk

Publication Type:Journal Article
Year of Publication:1983
Authors:Bechard, MJ
Journal:The Wilson Bulletin
Volume:95
Issue:2
Date Published:1983
ISBN Number:00435643
Keywords:Accipitridae, Buteo, Buteo swainsoni, Buteo swainsonii
Abstract:Clutch-size, brood-size, and fledging success were observed at 96 Swainson's Hawk (Buteo swainsoni) nests in both grazed and cultivated habitats in southeastern Washington. Except in 1977, nests in cultivated habitats fledged fewer young. Decreased fledging success resulted from high mortality of youngest and next youngest nestlings. Using nestling weight as an index of food supply, decreases in nestling weight and increases in weight discrepancies between youngest and oldest nestlings in cultivated habitats indicated that a dearth of food increased the incidence of brood reduction. These data supported the food-limited hypothesis for the adaptive significance of hatching asynchrony in this species.
URL:http://www.jstor.org/stable/4161753
Short Title:The Wilson Bulletin
Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith