Sunday, 26 April 2015

Spring Migrants: Wheatear

Wheatears are very cool birds. First of all, they are one of the first 'proper' spring migrants to arrive back in the UK and on Bardsey, usually reaching the island by mid-March. They are one of the harbingers of spring, and the males are always a delight to see. This species gets its English name from an altered version of 'White Arse', referring to the bird's white rump. There are two races that pass through the UK: the Northern Wheatear is the nominate race, which arrives in March and begins breeding by mid-April; the Greenland Wheatear is a larger, more orangey-toned bird which begins passing through in mid-April.

Although the species is handsome enough as it is, they undergo a pretty phenomenal migration, being said to be the largest of any passerine. For now I shall outline the migration of the Greenland-race Wheatear, as it is far more impressive than our British birds...Oenanthe oenanthe leucorhoa, as the Greenland Wheatear is Scientifically named, breeds in the Arctic tundra from Greenland across to western Alaska. After spending the summer months in the Arctic circle, the birds begin their southward migration in August. A recent study has shown that the Wheatears take one of two different routes to their wintering grounds in Africa, depending on where they breed in the tundra:

  • Birds from the eastern tundra take a route that goes via the UK, southern Europe and the Mediterranean to Western/Central Africa. Birds crossing the Atlantic to Britain average 850km per day for four whole days. Some will stop off in Greenland, and some birds may even bypass the UK entirely, using their fat reserves and tail winds to make a phenomenal 30-hour, non-stop flight of 2,500km straight from Greenland to Southern Europe!! 
  • The majority of bird breeding in the western tundra and Alaska taker an entirely different migration route: they fly across the Bering Sea, and track south-west across Asia, arriving in Western and Central Africa in about November to spend the winter here. Typical travel times have been described as being 91 days on their Southward migration, travelling on average 160km per day. On their northward migration they take just 55 days to arrive briskly on their breeding grounds, which equates to 250km per day.
Either way, that migration is pretty impressive for a bird that weighs about 20 grams...


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