Nest orientation and hatching success in the tree pipit Anthus trivialis

Abstract

Many open‐nesting bird species orient their nests relative to surrounding vegetation to avoid adverse environmental conditions. In eastern England, tree pipit Anthus trivialis nests predominantly faced east, an orientation that provided shelter from prevailing WSW winds, allowed warming by the morning sun and which, together with relatively high field layer cover, shaded nest contents from the midday sun. Mean orientation moved from south to north through the breeding season as temperatures increased, suggesting that solar radiation was a key influence on nest placement for tree pipits in the study area. Tree pipit nests with eastward orientations experienced better hatching success than those in less‐preferred orientations and it is suggested that this was due to their thermal advantages. In contrast, nest orientation had no influence on nestling survival.