Interspecific dominance and the foraging behaviour of juncos |
| |
Authors: | George C. Millikan Philip Gaddis H. Ronald Pulliam |
| |
Affiliation: | 2. American Museum of Natural History, Central Park at 79th Street, New York, NY 10024, USA;3. Department of Zoology, University of Georgia, Athens, GA, USA |
| |
Abstract: | We observed mixed groups of dark-eyed juncos (Junco hyemalis) and grey-headed juncos (Junco caniceps) at baited sites in northern Arizona during the non-breeding season. In interspecific and inter-racial conflicts, J. caniceps dorsalis was dominant to J. caniceps caniceps and to two races of dark-eyed juncos. Junco caniceps dorsalis also fed significantly faster than any of the other juncos. For both species, feeding rates were approximately the same in large and small mixed-species groups, though in larger groups, individual grey-headed juncos won conflicts at a higher rate and individual dark-eyed juncos lost conflicts at a higher rate. Also, dark-eyed juncos fed at a significantly lower rate in groups comprised mostly of grey-headed juncos than in groups of similar size but composed mostly of conspecifics. Residency times and recapture probabilities were similar for the two species, suggesting little difference in over-winter survival. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|