A day of British birdwatching that includes a flock of Snow Buntings is going to be memorable so just imagine what it was like to see a flock of 5,000 on one small field in Iceland.  There had been just enough snow to make most feeding areas inaccessible but the heads of an unharvested field of rye were standing proud above the white blanket.  As they caught the low winter sun, in flight, the Snow Buntings twinkled white and gold against the blue sky.  This was the biggest gathering that any Icelandic birdwatcher could recall and a wonderful picture of the spectacle filled a large part of the front page of the main Icelandic newspaper next day.

The birds we saw in Iceland were not all of Icelandic origin; many will have been birds that bred in Greenland and had moved to Iceland to take advantage of the warmer weather.  Much of lowland, western Iceland remains relatively snow-free in the wintertime.  Snow Buntings are really good examples of birds for which there are different migration strategies for males and females.  Males are keen to remain as close as possible to their breeding territories in the winter time.  If the spring weather starts to warm up early then they are well placed to spot an opportunity to get back to their breeding grounds and to establish good territories.  This explains why the birds that are seen on the East Anglian coast, where flocks of one hundred or more attract birdwatchers from across England, are mostly females.  As one moves further north through Britain, the proportion of male birds increases.

The Snow Buntings that we see in Britain are of two races, birds of the Icelandic race (which includes those breeding in Scotland) are joined by an unpredictable number of birds from further north.  In the hand, licensed bird-ringers, working as part of the British Trust for Ornithology’s ringing scheme, are able to take measurements of individual birds and to look at their plumage characteristics.  These features can determine whether birds have travelled from Iceland or from further north.  It is amazing to realise that many of these sparrow-sized birds will have travelled all the way from Greenland.  In contrast, birds that breed in Scotland hardly move at all, just dropping down to lower levels to feed in farmland.

Male Snow Buntings are really distinctive in the breeding season, with a striking white head and underparts, and black wings and back.  Females are better camouflaged, being brown and streaky above but white below.  In winter plumage the main colouration is a sandy brown but there is a flash of white from wings and outer tail feathers as they take off.  Adult, male birds of the northern race have the most white, whilst young, female birds of the Icelandic race have least white.

Graham Appleton (BTO)