Data from: Variation in nest characteristics and brooding patterns of female Black-throated Blue Warblers is associated with thermal cues

Thermal variation poses a problem for nesting birds and can result in
reduced offspring growth rates and survival. To increase the thermal
stability of the nest, females can adjust nest characteristics and nest
attendance in response to changes in environmental conditions. However, it
is unclear how and to what extent females modify parental behaviors during
various stages of offspring development. We tested the hypothesis that
females adjust nest characteristics and brooding patterns in response to
thermal variation during the nest-building and nestling stages,
respectively. We examined elevational variation in nest location, nest
construction, and brooding patterns in the migratory Black-throated Blue
Warbler (Setophaga caerulescens) across a 28C gradient at the Hubbard
Brook Experimental Forest, New Hampshire, USA. Density of woody stems at
nest sites and nest wall thickness increased from low to high elevation,
corresponding to decreasing temperatures, but we found no relationship
between weather during nest building and nest characteristics. However,
weather during the nestling stage was associated with female brooding
patterns: at lower temperatures and with higher rainfall, females spent
more time off the nest, which was associated with lower nestling mass near
fledging. These results suggest that thermal cues during nest building may
be unreliable as predictors of future conditions for developing nestlings
and also that females might favor their own self-maintenance and
compromise nestling growth under adverse thermal conditions.