Wiley, R. H.   1991.   Both high- and low-ranking white-throated sparrows find novel locations of food.   Auk 108:   8-15.


I examined the hypothesis that low-ranking White-throated Sparrows (Zonotrichia albicollis) during winter are more likely than high-ranking birds to find novel sources of food near a known feeding site. If so, high- and low-ranking birds might use different tactics while foraging, each with compensating advantages and disadvantages (Rohwer and Ewald 1981). I presented small, partially hidden concentrations of seed at random locations within 2 m of regularly supplied feeding sites, which were used by individually marked birds with known dominance relationships.

Individuals that found the novel sources of food included approximately equal numbers of birds in all four quartiles of the distribution of dominance proportions. Once the novel food

was found, disproportionate numbers of high-ranking birds tended to feed there. They gained access to the food in most cases by supplanting subordinates, whereas the low-ranking birds waited until they could approach the food without interactions. In addition, high-ranking birds usually left the food of their own accord, whereas low-ranking birds were usually supplanted by dominants.

These results suggest that high-ranking birds found new sources of food as often as low-ranking birds and also appropriated sources of food once found by others. I found no evidence that advantages in finding food compensated birds with low rank for disadvantages in competing for food once found.

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