The Use of Sheep Wool in Nest Construction by Hawaiian Birds

Abstract

The utilization of sheep wool as a nesting material was examined from 1969 through 1975 on the island of Hawaii. Of the 10 bird species studied, six incorporated wool into their nests. Both introduced and endemic birds use wool, with a significantly greater usage by endemic birds. Use of wool in nest construction appears correlated with the intricacy of the nest that a species builds, with a significant difference between degree of usage in complex and simple nests. Roughly built nests, like those of the Cardinal (Cardinalis cardinalis), contained no wool whereas the complex nest of the Elepaio (Chasiempis sandwichensis) had a great deal of wool. Wool is apparently used by the birds because it is a readily available material in certain areas, and because of its binding quality. The wool is gathered from tufts that snag on branches as the sheep pass or from dried skins on the ground. The amount of wool utilized in each nest varies both interspecifically and intraspecifically, but in all nests only the body of the nest contained wool, the lining always being of other materials. A separate study was conducted to determine if wool is used only when available nearby or is a sought-after material. Only the Elepaio was found to consistently travel distances to procure wool, whereas the other species studied used it only when available within their territories.