Effects of nest predation in the Siberian chipmunk Tamias sibiricus on success of the dusky warbler Phylloscopus fuscatus breeding [Russian]

摘要

The ability of Siberian chipmunks (Tamias sibiricus) to influence both the breeding success snd nest site selection of the dusky warblers Phylloscopus fuscatus appears to be unusually high. From traces on plasticine "eggs" put into dusky warbler nests short after predation it was deduced that chipmunks are well able to predate nestlings at an age of 7 days, although it makes a predator one or two days to empty completely a nest of 5 chicks. Twenty chipmunks may face 4 bird nests at an area of 1 ha overgrown with shrubs. The data obtained show that bird nests played a marginal role in the diet of chipmunks, whereas the breeding success of dusky warblers was related primarily on the density of chipmunks. Considering the strong pressure of selection that makes dusky warblers to avoid predation by chipmunks, the highly developed strategies of nest site selection seems to be probable.