Groeicurve en legbegin van de Zwarte Wouw Milvus migrans

Black Kites were censused in the Bliesgau in southwestern Germany, close to the French border, in 1995-98. The census plot averaged 250 km², of which 20% is forested. The area is characterised by valleys of the rivers Saar, Blies, Mandelbach and Bickenalb, The first kites arrive in mid-March. Black Kite territories numbered 5 in 1995, 6 in 1996, 5 in 1997 and 6 in 1998. Of 16 pairs, only one was non-breeding, two failed and the remaining 13 were successful. Based on aged nestlings (according to wing length), onset of laying was calculated to have occurred on 4, 10 and 12 April in 1997, and on 2, 12 and 24 April in 1998. This is earlier than results obtained in other areas in central Europe (possibly partly caused by different definitions of onset of laying, and different incubation periods used in calculations). A single nest was visited several times during the nestling period in 1998, in order to obtain measurements on wing length (stretched maximally) and body mass of two known-age nestlings (Table 1).