PARENT SESSION
Oral Session #23: Animal Ecology: Behavior and Sociobiology. Presiding: P. Brunkow.
Tuesday, August 7, 2001. 8:00 AM to 11:45 AM. Hall of Ideas E.
Feeding patch dynamics in Arabian babblers: effects of social structure and patch distribution.
Reynolds, Penny 1, Pesch, Meghan 1, 1
ABSTRACT- Traditionally, studies of cooperatively breeding birds have focused on indirect fitness benefits accruing to reproductive subordinates during the breeding period. However, during the non-reproductive period, behavioral strategies may be expected to reflect a more direct maximization of individual fitness. We studied non-breeding groups of Arabian babblers Turdoides squamiceps to determine how food intake of individual birds is affected by the interaction of food item distribution with within-group social dynamics. When food was located in a single patch, males were always more successful than females. Rate of food item delivery did not affect success rate of individuals; however, agonistic interactions increased significantly as delivery rates declined. In a two-patch system, males and females did not differ in success rates, but males made significantly more unsuccessful attempts than females and switched patches more frequently. High competitive weights (evaluated by success in obtaining food items) were neither consistent or related to reproductive dominance, but identity of low-ranked individuals did remain constant over time. Birds did not consistently choose the patch where intake rate was highest, but tended to form associations with specific individuals and avoid others. These data suggest that reproductive dominance rankings are not necessarily correlated with superior foraging success. Instead foraging strategies differ between the sexes as a result of the interaction of social interactions with the temporal and spatial distribution of food across a landscape.
KEY WORDS: Arabian babbler, Turdoides squamiceps, patch choice, dominance