WHERE AND WHEN TO FEED - SEX AND EXPERIENCE AFFECT ACCESS TO FOOD IN WINTERING SNOW BUNTINGS

In group-foraging species an individual's ability to feed in the most beneficial situations could influence its overall foraging success mor e than its ability to find and handle food. Here we examined whether s ex, age or site experience of individual snow buntings Plectrophenax n ivalis in winter flocks could help explain how frequently they were fo und in advantageous foraging situations. We found that inexperienced f emales were scarcer than expected in large hocks, that females fed les s often in the early parts of flock feeding bouts, and that older and more experienced birds were more likely to feed in central hock positi ons. In addition, the likelihood of moving around the feeding station increased more with hock size in females, while older birds were bette r at retaining access to the feeding patch. Previously reported differ ences in peck-rate between sex and age/experience categories of this s pecies are therefore likely to be magnified by differential access to sources of food. We suggest that experience may help individuals to in tegrate within the feeding flock, but aggression from larger males may cause females to delay feeding or to feed in smaller flocks.