Note: Effects of spring temperatures on the first egg-laying dates of the nuthatch (Sitta europaea)

Abstract

I examined long-term changes in the egg-laying dates of the nuthatch (Sitta auropaea) from 1982 to 2007 in the Hrvatsko Zagorje area (northwestern Croatia) in relation to mean spring temperature and to potential climate change effects. Negative correlations between egg-laying date and year, and egg-laying date and local mean spring temperatures (mean of March-April values) were statistically significant. Based on the linear regression slopes, the models indicate that in 2007, nuthatches laid 6.5 days earlier than in 1982. These results suggest that nuthatch breeding in the Hrvatsko Zagorje area responds to climate fluctuations by shifting the date of clutch initiation.