Monday, 23 November 2015

A walk along the Ribble

It was a cold start to the day, but beautiful nonetheless on the Ribble Estuary. I came across a small pool on the saltmarsh which held a flock of about 30 whooper swans, 70 shelduck, 100 wigeon and about 70 curlew on the bank. There were hundreds more wigeon close by, as well as flocks of golden plover and hundreds of lapwing and redshank.  A very impressive spectacle.

Suddenly I heard a shriek from behind me and a redshank disappeared into a ditch persued by a large falcon. The hunter missed its prey but over several minutes kept returning to the ditch and even hovered over it a couple of times, something which I've never seen a peregrine do before and which immediately made me suspect it might be something else.

This is clearly a juvenile bird, but which species? It has certain features which could make it lanner. For example it has an eyestripe, it appears to have a pale crown, it appears to have a contrasting underwing with dark underwing coverts and on a photo further down it appears to have a dark rump (peregrine should have a palish rump contrasting with the back).

On the otherhand, the underwing conrast is perhaps not as great as it should be for lanner and perhaps falls within the range of peregrine, and though the rump is dark the sides of the rump appear pale. So perhaps it's a peregrine after all, which of course would also be the most likely option. But what about the eyestripe? Also it appears quite long winged for peregrine.

And then there's the fact that it hovered. Is that relavent? The only references I can find to large falcons hovering all involve saker, but I don't believe it's a saker. I think that the hovering is a red herring.

It could be a hybrid, since falcons are notorious for hybridisation in captivity. It doesn't have jesses or any other signs of captivity, but it's a possibility.

However, my best guess is that it's a calidus-type peregrine, in otherwords a northern race peregrine. Calidus peregrines are large falcons, juveniles have eyestripes and they are long winged compared to the birds we are familiar with in the UK. In fact this bird fits calidus peregrine very well. If I'm correct, then it would be the second I have seen this year following one in Lincolnshire in March.

I've sent the photos off to raptor expert Dick Foresman and await his comments. I'll put them here if and when I get further information.

A hovering peregrine with such a distinct eyestripe?

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