VARIATION IN FORAGING BEHAVIOR AMONG NESTING STAGES OF FEMALE RED-FACED WARBLERS

Foraging rates and maneuvers were examined in breeding female Red-face d Warblers (Cardellina rubrifrons) among egg-laying, incubation, and n estling stages. All measures varied among nesting stages, with prey at tack rate and search speed significantly increasing from egg-laying to incubation through the nestling stage. During egg-laying and incubati on, birds gleaned stationary prey from a fixed perch, but shifted to h over-sallying for stationary prey during the nestling period. These dy namic behavioral patterns may reflect responses to variable time const raints and energetic costs associated with different stages of the nes ting cycle.