Clement 2010. Greenland Wheatear
So what's the verdict in Birdwatch, Richard? Can they or can't they?
"It is often assumed that the larger and usually more brightly plumaged Northern Wheatears that pass through Britain in spring are birds that belong to the northern subspecies
leucorhoa, which breeds in Iceland, Greenland and north-east Canada, west to about Hudson Bay. These are usually referred to as 'Greenland Wheaters'. While this may be a true reflection, there are other, more subtle, differences which need to be appreciated in these birds, which are one of the longest-distance migrants to pass through Britain.
Size and colour
Greenland Wheatears mainly differ from the slightly smaller and paler nominate
oenanthe by their rich or deeper buff underparts; this is often more heavily tinged orange-buff extending to the belly and flanks and is not restricted to the throat and breast as in most nominate birds. Adult males are usually deeper blue-grey on the upperparts, and both sexes have slightly deeper or broader black bands across the tips of the tail. Juveniles too are a distinctly deeper or richer brownish-buff on the underparts and slightly heavier brown on the upperparts.
It's not always that simple, however, and there are variations within the general rule of brighter plumage. As a result of wear or plumage abrasion, whiter birds may occur on passage in early to mid-spring and on the breeding areas from early summer onwards. In addition, many birds breeding in Iceland are considered to be intermediate in size and plumage and have previously been separated into their own subspecies
schiloeri. This form seems doubtfully distinguishable, however, and the differences are more likely to be clinal, with paler southern birds to more intense or deeper plumage in northern individuals. This is possibly also the case elsewhere within the range of nominate
oenanthe.
In size Greenland birds can be up to 20 per cent larger, especially in bill, wing and tail lengths, while the legs may be as much as a third longer. This difference is easily seen in birds at the extreme end of the size range – those that breed in Greenland and north-east Canada – but is less clear-cut in individuals that are closer to the size range of
oenanthe, which breeds in Britain and across most of Europe to western Siberia.
Measurements of birds in the hand show that male Greenland birds have wing lengths of 102-110 mm and female wings measure 100-108 mm, compared with lengths of 95-102 mm and 93-97 mm respectively for nominate breeding Northern Wheatears from western Europe. It is noteworthy that birds from the Faroes are intermediate in measurements, 97-103 mm and 95-101 mm respectively, and as such appear to be closer to
oenanthe than birds from Greenland.
It has also been claimed that birds which are full-chested and taller or more upright in stance and those which perch more readily on posts are Greenland. These characteristics need to be treated with caution, however, since newly arrived migrants of nominate
oenanthe can also appear this way, and it may have more to do with the familiarity of their surroundings than a characteristic trait."
Richard (I needed some typing practice!)
