Thursday, 5 February 2015

Cackling Goose

Today I thought I would go down to Cuckmere Haven and have a look for the Cackling Goose. I think it's been there for over a month now and I was just interested to see what a half sized Canada Goose would look like. Strange enough when I did find it I was surprised to see that it looked just like a half sized Canada Goose!

I think that I had expected it to be a lot harder to find. I had spent a lot of time doing a complete circuit of the western side of the river and of course it was in the very last group that I examined. Go anti-clockwise from the Golden Galleon car park if you want to save yourself time. I had examined a lot of Canada Geese. Is this one smaller than that one? Does it have a darker breast? It gets very confusing but when you do find the Cackling it really is half size and there can be no doubt.

Cackling Goose in the centre

Size is key to finding it but even if full size the bird would look different. It has a much darker breast and belly, darker grey upper parts, a shorter neck and a smaller, more pointed beak. In some lights it also takes on a slight purple sheen. This one has a white crescent neck ring. It also had a much different call to the Canada Geese.

Showing slight purple sheen

Now for the nerdy part. Is it a Ridgeway's (minima) or  Richardson's (hutchinsii).  Having read up on them, on balance, I would have to favour the minima due to size and colouring but on the other hand there is the neck ring. It presence does not rule out minima but it is more characteristic of the hutchinsii and even more so of a third variety the Aleutian (leucopareia).

The image below is lifted from

Identification and range of subspecies within the (Greater) Canada and (Lesser Canada) Cackling Goose Complex (Branta canadensis & B. hutchinsii).

Click here to see more detail

The minima on the left, if you add a neck ring, looks like the one I saw at the Cuckmere and again you can see the purple tinge coming through.

Cackling Goose - but no purple tinge in this light

And, the final question, is it an escapee or a vagrant. I have no way of knowing but I see no reason why it should not be a "real" bird. There have been other examples of vagrant Cackling Geese recorded and verified in europe from recovered rings.

More details on identification of subspecies here.

I didn't look at much else around the Cuckmere. I am not allowing mission creep any more having missed out on the Lesser Spotted Woodpecker on Monday, but I did stop to take a picture of these Barnacle Geese. There were five in total on the river side of the circuit.

Barnacle Geese

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