Zichtwaarneming van gezenderde Zweedse Bruine Kiekendief Circus aeruginosus

While counting migratory birds in the southwestern Netherlands, a transmittercarrying adult female Marsh Harrier Circus aeruginosus was observed on 14 September, around 9.27 h local time. The bird passed flying at a height of some 15 m, shortly gained height to cross the water of Hollandsch Diep, and was gone in no time, heading southwest. This bird had been ringed by the Migration Ecology Resarch Group of the Lund University (Sweden) at her nest near Kristianstad in South Sweden in 2005 (pers. com. Raymond Klaassen). She had also been recorded by Nils Kjellen whilst passing Falsterbo on 11 September 2008. Up till 2008, this female normally passed east of The Netherlands on her trip to her wintering site in West Africa (where Mauritania, Mali and Senegal converge). The strong easterlies in September 2008 probably had her displaced westwards, resulting in the observation in the Hoeksche Waard. In September 2008, five transmitter-carrying Marsh Harriers passed The Netherlands, out of only six Marsh Harriers with functioning transmitters. This included an adult male via Groesbeek on 13 September (11.00 h), which had spent the previous night in the Ooypolder. The latter is staggering, as Raymond Klaassen – involved in the migration project of Lund University – was bom in Groesbeek.