Brood Parasite and Host Coevolution: Interactions between Shiny Cowbirds and Two Species of Meadowlarks

Publisher Website
Google Scholar
Abstract
Host-parasite interactions of the shiny cowbird [Molothrus bonariensis] and 2 spp. of meadowlarks were studied on the Argentine pampas. The greater red-breasted meadowlark (Sturnella loyca) suffered a high rate of parasitism (23 of 24 nests) while S. defilippii appeared to escape parasitism (0 of 11 nests). Cowbirds visiting the study area associated preferentially with S. loyca, and approached decoys more often when S. loyca song was broadcast. The S. loyca is dependent on elevated perches and usually nests near them, while S. defilippii does not require such perches and does not nest near them. The perches nesr S. loyca nests apparently facilitated nest-finding by cowbirds. Female S. defilippii were more surreptitious than S. loyca females during nest-building, and although S. loyca females interrupted nest building when cowbirds arrived, the cowbirds were usually more patient and succeeded in finding nearly all of the nest observed. Mechanisms affecting cowbird nest selection, and growth and feeding of cowbird nestlings were discussed.

This publication has 0 references indexed in Scilit: