What has happened to the Canada Goose?

[Tringa]

The photos were taken on a local pond which is frequented by a variable number of Canada geese. I think they are part of a larger group that move around the ponds and lakes of east/NE London.

When I first saw this one I thought it could have been attacked by a dog or fox (though I did think there is easier food available for an urban fox than an adult goose), but then I noticed that the "injury" was on both sides.

Does any one know what could have happened to this goose?

Apologies for the poor photos. It was towards the end of a dull day and I had to up the ISO to 6400.

Dave

[Farplace]

Its got "angel wings" fairly common in ducks and geese. See here

[valleyforge]

Hi Tringa,

This would appear to be a fairly common condition of waterfowl that is typically known as 'Angel Wing', or 'Slipped Wing'.

It is a developmental problem, there being a couple of theories as to what causes it ... either a genetic disposition (often more than one sibling from the same clutch develops the problem), or a diet too rich in either proteins or sugars ... wherein the wing feathers emerge more rapidly than the musculature of the carpus (wrist) can develop to support their weight. That causes rotation at the wrist joint that is untreatable, unless the wing is strapped into the correct orientation as soon as the condition becomes evident ... that is often impossible to achieve however in hand-reared waterfowl, and probably not a consideration in a wild bird.

This causes the end of the wing to stick out laterally instead of tucking in neatly against the abdomen. Either one or both wings can be affected, but interestingly perhaps, in the case of just one wing showing this problem, it is usually the left one. Also, more male birds seem to be affected than females.

We currently have in care a young mallard drake who is affected on the left wing ... so that would tend to bear that out somewhat.

The condition isn't painful to the bird, but as you can see from this individual, the wing primary feathers can soon become tattered from snagging on things. The affected bird is also unable to fly, so longterm survival of this individual will depend largely on where it and its flock are located ... and if that is a safe site, perhaps with supplementary feeding by humans (which ironically, may have induced the condition in the first place).

[Tringa]

Thanks for your replies Far and Valley.

I have not seen this condition before.

For me it is interesting that a possible factor in the development of angel wing is supplementary feeding by humans.

The pond where I saw this goose is well known locally as somewhere where there is massive overfeeding. More than once I have seen loads of chapatis and a loaf of sliced bread floating in water.

Dave

[Ukwildlifeo]

There is a canada goose on my local park lake with this condition in one wing that has been there for years.

I've always assumed it was a genetic deformity, perhaps caused by the fact the species in the UK is descended from captive escapees/releases and perhaps a limited gene pool. Interesting to see other theories for the cause and what its called too

This lake is also subject to over feeding of birds. In school holidays the water is cover in unwanted bread, the only reason its not dead is due to a stream flowing in and out flushing out the pollution!

[tigertom]

Not seen angel wing on geese befor but is a pair of swans on local canal that always has one cygnet in its brood every year with this condition dont no why though its only ever just the one, this year it was one out of 8
MIKE

[thewoose]

Wow - there's a LOT of Canada Geese in my local park lake with this. I always thought it was a form of clipping undertaken by the wardens...but the lake is very much as Ukwildlifeo describes it above.

Feel bad for taking the kids down there with scraps of bread now

[Billabong Karen]

If this is the case, then surely local councils and/or environmental groups should take it upon themselves to put up signs requesting people NOT to feed the waterfowl? I know that in addition to causing developmental problems for ducks/geese, overfeeding with bread can also cause an explosion in the rat population, who then not only spread disease but also predate the ducklings/goslings... And the bread falling to the bottom of the pond causes further problems as it disintegrates.