Friday 22 July 2011

No ex-skuas!

During our time on North Ronaldsay and Westray, we did not encounter any resident birds of prey. However, we were able to watch skuas most days. They are the pirates of the seabird colonies, chasing and harrying their quarry to make them drop food, or simply attacking adults and chicks, without fear or favour. The species present were Great Skua, Stercorarius skua, known in the Northern Isles as a Bonxie, and Arctic Skua, Stercorarius parasiticus, also called Parasitic Skua, or known locally in Orkney as a Scootie Allan.

The Bonxies patrolled the cliffs looking for any opportunity that presented itself from the nesting Gannets, Guillemots, Razorbills, Puffins or Kittiwakes. The Arctic Skuas tended to concentrate on the Arctic Tern colonies, though we also saw them targeting Black Guillemots.

This is a Bonxie, scavenging on a dead Eider Duck, on the coast at Dennis Ness on North Ron.

These are more or less consecutive shots of an Arctic Skua, also at Dennis Ness on North Ron. There were a pair of these birds that loitered on the ground between the lighthouse and the the small water body of Trolla Vatn. We assumed that they were watching and waiting for terns to show up. We saw them regularly, as we visited the Lighthouse Cafe most days, so I suppose they could've been waiting to see if they could make us disgorge our lunch!

One evening on Westray, the Admiral and I were watching a Black Guillemot that was sat on the edge of a low cliff. It had caught a butterfish and was trying to ensure that no marauding predator  could follow it to its nest site. Seemingly, from out of nowhere, an Arctic Skua zoomed across the storm beach, mere inches from the ground. The guillemot, sensing the danger, hopped off the edge of the cliff and disappeared out of sight. Given the skua's closing speed, I couldn't see how it was going to give immediate chase, without flying passed, out over the sea and doing a u-turn. Not a problem. At undiminished speed, as it reached the cliff top, the skua rolled through 180 degrees and dived vertically after the guillemot! I've no idea what happened next, but it was a mightily impressive display of aerial agility. I imagined the guillemot opening its beak to mutter some profanity at the turn of events and thereby losing its butterfish. 

Here's a brace of Bonxies over Bow Head on the northern tip of Westray. Not a sight to fill the hearts of any nesting seabird with joy, as their shadows raced over the jagged rocks like sombre angels of doom.

More uplifting tales of sweetness and light, next time, on I&T.

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