Thursday, October 11, 2007 - U-turning eagles
Last weekend I was - again - on Rönnskär. But enough of that, instead what follows is a brief and superficial lesson in the migration routes of raptors on the south-coast of Finland.
As you probably know, birds with a large wing-surface use rising thermal currents when migrating. They save energy by soaring in these currents and then gliding forward from the great heights. Not much energy-consuming flapping of wings needed. So - let's remember that we are on an island in the Gulf of Finland a bit out to sea from Porkkala peninsula. The Gulf of Finland is at it's narrowest here, only about 50 kilometers of water separate finnish and estonian mainlands. From Rönnskär you can often when the weather is good see the tree tops (but not the shore-line, curvature of the planets' surface, you see) in Naissaari, an island near the coast of Estonia. So - as there are no rising currents out above the sea, large birds tend to avoid crossing the sea - eagles being a good example. And during the weekends' migration-watching we had a few nice examples of this.
Saturday was a good day for raptor-migration. We counted 161 Sparrowhawks heading South. They don't care about the sea much. (Eurasian) Buzzards came in large flocks and soared so high that they sometimes disappeared in the clouds, we counted 222 of them, some of them intimidated by crossing the sea, headed back to the mainland. One Golden Eagle was seen soaring above the mainland (about 4-5 kilometers away), it never came over the sea, it headed back to mainland. Often these eagles that come to the southern tips of peninsulas sticking to the sea later follow the coast-line towards East. They go round the Gulf of Finland on the Karelian Isthmus, raptor migration can be quite impressive there.
The star bird of the day was also an eagle - a juvenile Greater Spotted Eagle. There it came, flying casually across the sea. Janne found it, what is it with him and this species ( "Nanne sees a clanga"), there's something weird about it... With its wings arched down the eagle headed straight for us, flew straight over us and headed towards the southernmost island of the archipelago where it decided it wouldn't cross the sea, made a u-turn and headed back to the mainland.
On Sunday the migration was much slower - or less visible. Still, we had three more u-turns as a flock of three Golden Eagles flew a bit out to sea before returning to the mainland. As to stress my point.
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Me - Timo Janhonen
Fabulous birding adventures on the south coast of Finland.
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