Rare vagrant appears
SEPTEMBER ended with more warbler rarities.
A Syke’s warbler was identified at Sumburgh on the 25th by Roger Riddington and Paul Harvey. A very rare vagrant from south-west Asia, there are only a handful of Scottish records and these all come from the Northern Isles – Orkney, Fair Isle and Shetland.
Syke’s warbler was only recognised as a separate species in 2002; previously it was regarded as a race of the booted warbler. When it was elevated to species status, two previous Fair Isle records of booted warbler which were reviewed by the British Birds Recording Committee (BBRC) were subsequently accepted as the first and second British and Scottish records of Syke’s warbler.
In 1993 there was one in Lerwick which stayed around from 22nd October to 9th November, allowing several observations. It was noted that it was larger than a booted warbler with a longer, heavier bill and its behaviour and calls suggested it might be a Syke’s. This bird was subsequently trapped and close examination and measurements confirmed the identification.
Syke’s warbler breeds from Oman to Turkistan and west China, and migrates to winter in India alongside booted warblers.
Another tricky warbler was found at Lunna on the 27th. Western Bonelli’s warbler, a very rare vagrant from south-west Europe or north-west Africa, is also a comparatively recently recognised species.
Up until 1997 all the British records were treated as Bonelli’s warbler. This warbler is slightly smaller than a willow warbler with white underparts, greenish-brown upperparts and a yellowish rump. The wing feathers and tail feathers are edged light yellowish-green.
All previously published records prior to 1997 were reviewed by the BBRC, and 10 of the Scottish records were accepted as western Bonelli’s warblers. Eastern and western Bonelli’s warblers were now recognised as different species.
Other migrants of national importance were the eastern olivaceous warbler which was still on Foula on the 26th, Blyth’s reed warbler, one on Foula and two recorded in the South Mainland, a red-flanked bluetail and a bobolink, both on Foula.
A bobolink is a very rare vagrant from North America with only a handful of Shetland records. It resembles a female house sparrow but has a distinctively striped crown and is yellowish-white below. Bobolinks breed in the northern United States and southern parts of Canada and winter south of the equator, mostly in Argentina.
Local rarities this week included marsh warbler, pectoral sandpiper, American golden plover, short-toed lark (Foula), hobby, kingfisher (the Cunningsburgh bird relocated to Hoswick on the 25th) and a ring-necked duck (Foula). Several yellow-browed warblers were recorded from various locations along with a scattering of common migrants.
Charles Hughson photographed a leucistic starling at Cunningsburgh. Leucistic birds are paler in colour than is normal for the species but they do not have the total lack of pigment of an albino.
Visiting the bird feeders, we have a distinctive sparrow which has a single white tail feather but more comical is the male blackbird which has a patch of white feathers on the right hand side of his crown – as though he is wearing a rakish hat.