Thursday, June 17, 2010

In the heat of the midday sun

One of the most beautiful of gulls is, in my opinion, the Kittiwake or, as now known, Black-legged Kittiwake. This bird breeds in the North Atlantic and disperses south to the waters around the Strait of Gibraltar and even further down the Atlantic coast of North Africa. But its winter numbers are heavily dependent on weather conditions. If we get long periods of severe south-westerlies, then many birds that are wintering out at sea in the Atlantic get pushed inshore. During such times many get beached and die. I remember years with tens of thousands of Kittiwakes around our coasts in December and January, even as late as March.

We find fossil Kittiwakes in our caves, going back 50 thousand years. It is possible that many more came down to winter here during the glacial periods but the numbers of this and other seabirds suggests that they may even have bred in these latitudes. It is tempting to imagine colonies of Kittiwakes on the cliffs of the Rock of Gibraltar, just as we find them on the Farnes today.
Even in high latitudes, Kittiwakes nesting in exposed rock ledges suffer the heat of the midday sun on warm days. What would they have done in the strong sun of lower latitudes, even during glacials?
Adults and chicks panting hard to lose heat

adult trying to shade a chick

chicks' dilemma - do I eat or keep cool?

perhaps an afternoon siesta is the solution...