Meeting Abstract
While the majority of incubation in birds occurs after the completion of egg laying, in some species, parents often begin incubation prior to clutch completion. Consequently, eggs within clutches typically develop and hatch asynchronously, often resulting in reduced rates of growth and survival among later-hatched nestlings. In many species, incubation prior to clutch completion and hatching asynchrony are associated with high ambient temperatures. Prolonged exposure to high, suboptimal temperatures can result in abnormal development and negatively affect the viability of eggs. Thus, when ambient temperatures are high, incubation prior to clutch completion may serve to minimize reductions in the hatching success of eggs by expediting the hatching of the earliest laid eggs. Here, we used information collected by automated data-loggers (iButtons) to model the effect of ambient temperatures on the incubation behavior of European starlings (Sturnus vulgaris), a cavity nestling species, prior to clutch completion. By placing data-loggers externally on the underside of each next box as well as within the cup of each nest, we were able to record ambient and nest temperatures for each nest over the course of the laying period. We found that, while nest cup temperature and the likelihood that eggs experience temperatures necessary for embryonic develop are strongly influenced by ambient temperature, nest attentiveness – inferred by comparing external and nest cup temperatures – appears to be unrelated to ambient temperature. Together these results suggest that while incubation prior to clutch completion and hatching asynchrony may be associated with high ambient temperatures, this relationship does not reflect a change in incubation behavior as a response to high ambient temperatures.
