Bleksanger Hippolais pallida – ny for Norges fauna

Sammendrag

Eastern Olivaceous Warbler - Hippolais pallida - new to Norway

Norway’s first Eastern Olivaceous Warbler Hippolais pallida was recorded on 12th September 2004. An adult of this species was caught in a mist-net at Titran in the island municipality of Frøya, off the coast of Sør-Trøndelag county in Central Norway. Hippolais pallida was previously on the list of birds recorded in Norway, but due to uncertainty about the identification of grey species of Hippolais, the record was changed in 1994 to that of unidentified H. rama/H. pallida. The Titran bird was of the eastern race H. p. elaeica, which occurs regularly in south-eastern Europe and central Asia. It does not breed west of Slovakia, and winters in East Africa, north of Lake Victoria, and on the Arabian Peninsula. Only a few countries in central and northern Europe have records of the Eastern Olivaceous Warbler. The majority of these are from Britain, but it has also been observed in Ireland, Austria, Finland, Sweden and Denmark, and now in Norway. Though several south-eastern European countries have reported a decrease in their populations, Greece and Turkey still hold populations of 100 000-150 000 and 500 000-5 million breeding pairs respectively. It is therefore natural to assume a large number of records in northern and western Europe resulting from prolonged spring migration or reversed autumn migration. However, the Alps and the Carpathians seem to make an effective barrier, and in Germany only three records have been reported from 1883-2000. Despite the Eastern Olivaceous Warbler breeding in Austria’s neighbouring countries of Slovakia and Hungary, there is only one confirmed record in Austria itself. Britain had 11 records up to 2003, while Ireland had 4 up to 1999. In the Nordic countries a total of eight records have been reported. The two latest records, from autumn 2004, in Norway and Sweden respectively, have not yet been treated by their countries’ rarities committees. However, they were both convincingly documented. The Eastern Olivaceous Warbler is a pale and insignificant warbler with few distinct characters. It is easily confused with other Hippolais species like H. rama, H. opaca and H. caligata. It can even be confused with H. languida and Acrocephalus dumetorum. As shown in the photos, P1 was about 4- 5 mm longer than the secondaries of the Titran bird. The tail was relatively narrow and straight with long outer tail feathers. The edge of the wing was also straight, excluding Acrocephalus dumetorum, and the shape of the bill excluded H. opaca. The bird’s plumage was without olive green, resulting in a rather light grey impression, also from above. A general identification of the Eastern Olivaceous Warbler is discussed further in comparison with the possible confusion species mentioned above.