A birding mystery solved?

A few days ago I gave you a little mystery to solve. If you haven’t already looked at it and want to form an opinion first, the post is HERE. Otherwise, follow on for the answer.

We are looking at a set of evidence here, and trying to answer two questions:

  • What died?
  • How did it die?

So let’s start with the first question. What was this?

The foot has webbing, which tells us this is a water bird, such as a duck or a gull. It’s also quite a bright red, which narrows our choices down. we also had a feather to go on.

This shape of feather tells us it is from the wing of the bird, what’s called a flight feather. By looking at this feather, we can tell something about the colour of the wing of the bird. Predominantly white/light-grey, but with a black tip. This does suggest a particular bird.

If we look at the outstretched wing of this Black-headed Gull, we can see the feathers 3 or 4 in from the edge of the wing have this same pattern. Does it have red webbed feet?

Indeed it does. So I think that’s our poor victim here. Quite a few people got it right, but Me and My Hats was first on the blog.

Shelduck was suggested online, but there’s more black in their primaries. Mediterranean Gull was close, but they don’t have the same amount of black on the wing tips.

But what about question two? What happened?

Well, when you have piles of feathers and odd strewn limbs, it’s a fair bet we are dealing with a predator rather than natural causes.

A dog/fox/cat wouldn’t generally have spent so long neatly plucking the bird, so I would rule them out.

So I think we are in the realms of birds of prey here. In terms of the location, Peregrine and Sparrowhawk are the most obvious candidates. A Peregrine would generally take the bird away to pluck at a high vantage point, scattering remains on the breeze. But a Sparrowhawk will often pluck and dismember on the ground.

It isn’t a perfect example of a Sparrowhawk kill, as often you will find more of the carcass left behind, meat stripped from the breast. But given the number of scavengers around the bird may have felt it necessary to take it away somewhere more quiet. It’s also possible that the remains were dragged off later by another animal.

So, though we cannot be certain, I think this is a Sparrowhawk kill. It would have to be a female as the male is far too small to take a Black-headed Gull.

Do you agree with my conclusions? If not, feel free to use the comments to tell me why I’m wrong!

Addendum – Martin Kitching and Bob Askwith via the Yorkshire Birds and Birders Facebook group have both said they have often seen Peregrines eat prey at the kill site rather than take it away. With that in mind, I think we have to leave a note of doubt here and say ‘A bird of prey, probably a Peregrine or a Sparrowhawk’.

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I welcome thoughts, comments and questions, so please feel free to share anything at all. Thanks, David

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