Sex, Dominance, and Microhabitat use in Wintering Black‐Capped Chickadees: A Field Experiment

I studied foraging patterns of Black—capped Chickadees (Parus articapillus) wintering in flocks in poplar forests of central Alberta, Canada. Females exploited highest and outermost tree parts, while males (which socially dominate females) foraged low and close to trunks. Females spent more time probing and found fewer prey per probe than males, but both sexes had similar feeding rates. I temporarily removed all eight males from three flocks, females foraged lower and closer to trunks than in three control flocks. Experimental females spent less time probing than controls, but had similar feeding rates. When captive males were released, they returned to their flock and experimental females shifted back to their initial foraging behavior. The results show that sex—specific foraging patterns in this population were affected by avoidance by females of microhabitats used mostly by dominant males. I suggest that predator avoidance makes the tree parts exploited by males more profitable.