Nest box reuse in a migrating bird is independent of nest content

Abstract

Site fidelity after successful nesting is an adaptation to spatially heterogeneous and temporally auto-correlated risk of nest predation. Cavity-nesting common goldeneye (Bucephala clangula) females use this strategy to minimize nest predation from pine marten (Martes martes), but because goldeneyes migrate they may save time when deciding where to nest by relying on information about successful nests gained in the previous year. I tested whether reuse of a nest box where the previous nest was successful is affected by the content. After a goldeneye had successfully nested, I manipulated nest box availability by offering two nest boxes; one in the original nest tree and one in a new tree for the season, each containing either old nest material from the successful nest or new nest material, i.e. wood shavings. The boxes were installed and relocated when goldeneyes were absent from the study area. The manipulation was designed to test whether goldeneyes reuse a cavity based on information conveyed by its current content, or on private or public information gained in the previous nesting season. Goldeneyes consistently reused the box in the original nest tree, independent of box content. Thus, when the information available in the current nesting season conflicted with information acquired in the previous nesting season, the goldeneyes relied on the latter rather than on information that would cost valuable time to update after arrival in spring. The common practice among ornithologists and land managers to clean nest boxes after each nesting would not affect cavity reuse in the goldeneye.