Sunday, 5 April 2015

Next Term, 8: Whitethroat

Probably the most colourful common warbler expected in these parts in a few weeks is the Whitethroat. The male has pink underparts, a brown back, warm rufous wings, a peaked grey head, white outer tail feathers, and of course a noticeably white throat.
Common Whitethroat

Most warblers are skulking birds and can be quite difficult to see, but the easiest time to see many of them is shortly after they arrive back from Africa. Whitethroats often perch on the top of a hedgerow, fence, post or barbed wire singing their scratchy, but cheerful short song. In these early weeks the males get so full of testosterone that every so often they launch into a fairly short jerky song flight - like a puppet on a string, before returning to the hedge top.
Whitethroats usually nest on the top of nettles, hopefully protected by brambles, gorse or some other impenetrable undergrowth. For this reason one of their old country names was Nettlecreeper. Other vernacular names include the one favoured by our late old local countryman, Ernie Teal: the Peggy Whitethroat.
In 1968 the Whitethroat was the commonest summer visitor when it left in September, but the following year only around 25% of those birds returned. It took a while for this sudden catastrophic loss to be properly understood, but it is now generally accepted that in that year there was a particularly pernicious drought in the Sahara. Like many summer visitors the Whitethroat has to cross the Sahara twice a year. Unlike some other migrants the Whitethroat tries to cross the Sahara in one crossing, but that year the Sahara was suddenly a lot wider than in previous years, and many individuals simply perished trying to cross this arid barrier.  During dry spring migration times Whitethroats will even stop over in suburban and urban gardens, which are well-stocked with water before moving on to their prospective breeding grounds.
A Whitethroat migrating through the garden during a dry spring
 A Bird on Autumn Migration
Since 1968 the Whitethroat has slowly increased its population but it is no longer the commonest summer visitor, and it's numbers have never reached its pre-1969 levels. Despite this severe slump we still have plenty of Whitethroats in East Yorkshire, and once they are back around the 20th of April we should see them almost every week of spring. 

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