ARCTIC visitors dominate the records this week, with up to six Iceland and three glaucous gulls at the Shetland Catch factory in Lerwick, 22 Slavonian grebes at Laxfirth, Tingwall, 26 little auks reported during a seawatch at Sumburgh Head and 65 fieldfares at Quendale.
Iceland and glaucous gulls are scarce passage migrants and winter visitors, both species being recognised at all plumage stages by the white tips of the primary feathers.
Slavonian grebe is also a scarce passage migrant and winter visitor, with an estimated 80 to 100 birds regularly over-wintering in Shetland waters. The highest number is usually recorded in the West Mainland.
It is a small grebe, about the size of a teal, with a flat-topped head and sloping forehead. In winter plumage it is dark above and pale below with a clear-cut black cap.
The populations of Slavonian grebe which breed in Iceland, Northern Norway and Scotland have longer, broader bills than the populations which breed east of Norway and it is these birds which over-winter here. Around 30 to 80 pairs of Slavonian grebe breed in the Scottish Highlands, with breeding first being recorded at Loch Laide, Inverness, in 1909.
Little auks are fairly common passage migrants and winter visitors. This species breeds in the high Arctic and moves south into the North Sea in late autumn. It is estimated that there may be up to a million over-wintering little auks offshore but only a small fraction of this population is recorded in coastal waters. Most are seen in Shetland and Orkney, often after storms.
In Shetland, peak numbers are usually recorded offshore in November but movements can continue into December and even January. In late December 2002, over 700 were recorded flying past Sumburgh Head in two and half hours. However, numbers vary greatly between winters. It is known that little auks have been visiting Scottish coastal waters for thousands of years as their remains have been found at archaeological sites.
A few small migrants linger on in sheltered gardens, with a waxwing, a couple of siskins and a dunnock in Lerwick, and the coal tit still at Sandgarth, Voe. There are usually a number of over-wintering robins at this time of year, such as the one which visits our garden.
As the shortest day of the year approaches, bird observations become confined to the weekend, as many commuters are leaving and returning home before sunrise and after sunset. However, an occasional bonus is a rosy, luminous winter sunrise, particularly beautiful when reflected in the sea or a loch.