Behavioral and Ecological Correlates of Interference Competition Among Some Hawaiian Drepanidinae

Carothers, John

Interference interactions were studied on the island of Maui among four species of drepanidines that fed on canopy flowers of the ohia tree. The birds had a size-related dominance hierarchy, with ranking as follows: Crested Honeycreepers, Iiwis, and Common Amakihi. Immatures were subordinate to conspecific adults. Crested honeycreepers and Iiwis defended tree-canopy territories, Apapanes were nomadic flock foragers, and Common Amakihis were secretive foragers. Dominance by Iiwis was indicated by a lack of reversals in the dominance matrix. For the top-ranked Crested Honeycreeper dominance was also reflected in greater chase or greater resulting retreat distances or both. Age-related differences in interference behavior by dominants appeared to be due to inexperience, as indicated by shorter chase distances for immatures. Among subordinates both experience and plumage could be responsible for age differences in behavior. Immatures were chased equal distances but less often than adults, and they chose safer retreat sites.

Behavioral and Ecological Correlates of Interference Competition Among Some Hawaiian Drepanidinae

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