Meeting Abstract

P1.188  Friday, Jan. 4  Energy Budgets for Florida Scrub-jays: a Changing Landscape Matters ELLIS, H.I.*; BOWMAN, R.; University of San Diego; Archbold Biological Station ellis@sandiego.edu

Field metabolic rates (FMR) were measured on Florida scrub-jays (Aphelecoma coerulescens) in two habitats using doubly labeled water. One group of jays lived in wildland habitat; the other in a suburban area where the habitat was badly degraded. During the breeding season FMR of suburban birds exceeded that of wildland birds by up to 100% (in males; less in females, but they may be fed at the nest by helpers). This very high cost may help explain why suburban jay populations are sinks. Wildland FMRs are about 3 x BMR during breeding; for suburban males, it is 6 x BMR. Jays from both habitats have an FMR only 1.5-2.0 x BMR in winter and fall, so it is the breeding season that separates them energetically. A low water economy index (mL/kJ) and low water fluxes in both habitats indicate that these jays are well adapted to their xeric habitat. (All doubly labeled water samples were analyzed in the lab of Ken Nagy at UCLA; this work was facilitated by Glen Woolfenden, now deceased.)