1 research outputs found
Do extended incubation recesses carry fitness costs in two cavity-nesting birds ?
Because extended incubation recesses, where incubating songbirds are away from nests for
periods much longer than usual, occur infrequently, they have been treated as outliers in most previous studies
and thus overlooked. However, egg temperatures can potentially fall below the physiological zero temperature
during extended recesses, potentially affecting developing embryos. As such, evaluating extended recesses in an
ecological context and identifying their possible fitness effects are important. With this aim, we used iButton
data loggers to monitor the incubation behavior of female Blue Tits (Cyanistes caeruleus) and Great Tits (Parus
major) during two breeding seasons in central Spain. We classified incubation recesses as extended if they were
more than four times the mean recess duration for each species. Extended incubation recesses occurred more
frequently in 2012 when females exhibited poorer body condition. Female Blue Tits had more extended
incubation recesses than female Great Tits and, for both species, more extended recesses occurred at the
beginning of the breeding season. Both nest attentiveness and average minimum nest temperature decreased
when at least one extended recess occurred. Incubation periods averaged 4 d longer for nests where females
had at least one extended recess, potentially increasing predation risk and resulting in lower-quality nestlings.
Overall, our results suggest that extended recesses may be more common among songbirds than previously
thought and that, due to their effects on egg temperatures and attentiveness, they could impose fitness costs.info:eu-repo/semantics/publishedVersio