Response of the Blackcap (Sylvia atricapilla L.) to temperature change

Many authors have demonstrated use of plants and animals as sensitive biomonitors for climate changes. This research was conducted in the Mokrice area (mixed agricultural landscape and small deciduous woods) in northwestern Croatia and studies cover the period from 1979 to 2007. This paper assesses evidence that year and local air temperature changes influence first arrival dates of the migratory passerine Blackcap, Sylvia atricapilla. The mean first arrival date of the Blackcap was 2 April (1979-2007). Correlation between timing of arrivals and year was significant (P <0.001). Blackcap arrival dates have become 9.3 days earlier during the research period (slope of linear regression = -0.32 [plus or minus] 0.01). The relationship between spring temperatures (March-April) and year (P = 0.019), and spring temperatures and timing of arrival (P <0.001) was also significant. This result suggests that Blackcap respond to spring temperatures by earlier arrivalat breeding grounds.