Voorjaarsfenologie van Spreeuwen Sturnus vulgaris

Bijlsma R.G. 2013. Spring phenology of Starlings Sturnus vulgaris. Drentse Vogels 27: . In the small village of Diever, western Drenthe, Starlings were present throughout the year, including winter time. Singing Starlings were recorded here during fine weather in January or February, usually close to previous nesting sites. This behaviour contrasted with Starlings nesting in nearby forests, where Starlings were absent except for the breeding period. Arrival dates in 1993 varied here between 24 February and 17 March for males and between 24 February and 19 March for females; in 1998 arrivals for males were between 9 and 15 March, for females between 11 and 20 March. The extended arrival schedule in 1993 was probably due to low temperatures in January through March (monthly means resp. 0.4, -0.3 and 0.2ºC in 1993, compared to 1.5, 3.0 and 3.0ºC in 1998). Despite the extensive arrival time in 1993, mean onset of laying in 1993 was two days earlier than in 1998 (Table 1). Between 1995 and 2003, first arrival dates gradually became later and later. Delayed arrival was parallelled by a decline in breeding numbers; the local study population was lost in 2004. Since then, Starlings were absent from the forested study site in early spring, and if a singing male was still recorded, then often late in spring, unpaired and for a short period of time only (no more than a day, usually gone within 15 minutes).