We used multivariate analysis to identify factors correlated with level
of subcutaneous fat (a form of stored energy) in a migratory, wintering
population of white-throated sparrows (Zonotrichia albicollis).
Dominant birds, residents from previous years, and birds residing in
certain regions of the study area tended to have high mean fat levels
during January and February. On the basis of differences
in levels of fat, dominant prior residents could probably survive 50%
longer without food than subordinate newcomers.
An additional analysis revealed that dominant sparrows returned more
frequently to the study area than subordinates, a result that might
indicate higher survival.