VARIATION IN FORAGING BEHAVIOR, DIET, AND TIME OF BREEDING OF FLORIDA SCRUB-JAYS IN SUBURBAN AND WILDLAND HABITATS

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Abstract
Supplemental food enables some birds to lay eggs earlier, perhaps by allowing birds to increase their energy intake or allocate energy from other activities to reproduction. We examined the relationships between prelaying behavior, food handling and consumption rates, and the timing of breeding of female Florida Scrub-Jays (Aphelocoma coerulescens ) in suburban and wildland habitats. Scrub-jays in suburban habitats had access to ad libitum human-provided foods; wildland jays did not. During both years of this study, suburban scrub-jays bred earlier than their wildland counterparts. Wildland scrub-jays bred earlier in 1997 than in 1996, but the timing of breeding by suburban scrub-jays did not vary between years. Suburban scrub-jays spent less time foraging and more time perching than wildland jays. They handled more food per hour and per foraging hour, suggesting their foraging was more efficient. Despite this, food consumption rates did not differ between the two habitats. Neither time spent foraging or perching nor food consumption rates significantly influenced variation in time of breeding among individuals. Time of breeding was significantly influ- enced by site, year, and rate of food handling. Individuals that handled more food items per foraging hour, that is, those individuals that were most efficient, were the earliest breeders in both habitats. These results suggest that foraging efficiency increases with access to human-provided food and that resource predictability may be a perceptual cue for the ap- propriate timing of breeding.

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