Dutch Birding volume 25 (2003) no 5

Greenish Warbler breeding on Schiermonnikoog in May-July 2003

In May-July 2003, a pair of Greenish Warblers Phylloscopus trochiloides raised three young on Schiermonnikoog, Friesland, the Netherlands, in the Wadden Sea off the north-east coast. The first bird (a singing male) was seen on 31 May. The supposed female was first seen and heard on 5 June. A second singing bird was reported on several days up to 11 June. On 21 July, the first young was noticed and, in the following days, three young and two parents were observed. The last sighting was on 29 July. Feeding was observed on a few occasions. Begging calls and subsong of the young were recorded on tape. The young birds had a shorter, more metallic, call than the well-known disyllabic call of the parents. The breeding area consisted of large well-wooded gardens on the outskirts of the island's only village (53:28 N, 06:09 E). In the evening of 29 July (the first day of the autumn's ringing season on the island), a first-year Greenish Warbler was trapped and ringed at Groene Glop, c 1200 m east of the breeding site. This bird still showed some downy feathers on the underparts and is likely to have been one of the young raised in the village. The identification and vocalizations are described and shown in sonagrams (figure 1-5) and details on breeding habitat and behaviour are given.

There have been 30 records of this species for the Netherlands. Eight were in spring (between 23 May and 30 June) and the rest in early autumn (between 9 August and 1 October). This was not only the first breeding for the Netherlands but also the westernmost for the species to date. The previous most westerly breeding record (and the only successful breeding record for Germany up to 2003) was in 1990 on Helgoland, Schleswig-Holstein, in the North Sea off the German north-west coast. Its regular breeding range (subspecies P t viridanus) is from eastern Europe, Gotland (Sweden) and Finland east to eastern Siberia en south to Afghanistan and Kashmir. The breeding range has expanded westward in the 20th century.

Enno B Ebels, Joseph Haydnlaan 4, 3533 AE Utrecht, Nederland
ebelswxs.nl