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The 19-year, 1,700 mile mystery


One of the things that I have learned while being a bone collector is how much you can sometimes learn about an animals life even from a single bone. You can tell if it died old (bones get slightly lighter in old age, and extra fusion occurs) or young, if it was healthy or if it had any injuries, and sometimes whether it was male or female (sometimes from the size or muscle attachments).

I had to put these skills to the test last week when me and my friend Jacob found a very unusual bone a 150 year old ice house. I have blogged about finding cool bones here but none quite as interesting as the one I found last week - or with as much information about the animal they came from !

Jacob came over a couple of weekends ago, and he was keen to look for bones. There were a few places which I knew were good for finding bones, but on the Sunday it was wet and cold, so I had to think of a place where there would be bones, but would also be out of the rain. That made me think of the ice houses on the old country estate on the other side of the village.

The ice houses

I have hadn't been back to the ice houses in ages. There are two of them built into the side of banks, each side of where the old Ardoch House used to be. The west ice house is closest, about a fifteen minute walk from my house. On the way walking up there we saw buzzards as well as a red kite that nests nearby.

The ice house has a short corridor leading to what looks like a window which looks out onto the main chamber.

Hundreds of years ago, when people did not have fridges, they stored their meat in a ice house. The east ice house is much shallower, but the west one is quite deep, and it's only now that I'm taller that I can get down and back up. At the bottom of the ice houses are a load of things that have been dumped, including the bones of animals that were dumped there. We took out our torches and climbed down into the darkness.

When we got down there, we noticed that their was some red deer skulls, which is unusual because the red deer don't come down off the hills to the village. After about half an hour of being down there, we found a couple of interesting bones like a roe deer buck with antlers and a duck skull. Then when we were just about to climb out,  Jacob saw a strange bone with something else as well that I will come onto later.

The bone

I recognised the type of bone right away: it's a left tarsometatarsus which is a lower leg bone from a bird, and the three ends are for the toes. I've seen quite a lot of these in those woods, especially from pheasants (which have a spike or spur at right angles half way down)

The thing that was most unusual was the thickness and the size of it. This one was massive, and the first thought I had was that the size of bird it came from would have to be something the size of a white-tailed sea eagle, red kite or golden eagle. All those birds are some of the most protected species in the UK. 

It was getting dark, and the best thing to do seemed to be to take what we had found home to investigate further.

The first thing I checked with when I got home was with my copy of "A manual for the identification of bird bones from archeological sites", which is a brilliant guide to identifying bird bones, although it doesn't list every species. The other great thing about the guide is that it shows each bone at actual size. So here's the bone next to the entry for the white-tailed sea eagle (the guide doesn't list golden eagle or red kite).

The length of the bone was just about right, but the shaft of the bone I found was much slimmer.The bone I found also didn't seem to have the large ridge pointing at the back of the bone, but my bone was broken there. The biggest difference, though was in the the toe attachments - the three 'trochleae ' or toe attachments, at the bottom. The manual pointed out that in birds of prey, these are all the same length, but on my bone one was much much shorter than the other

I had seen this before, on some birds that live near water, like cranes or gulls (but not on others, like cormorants or heron). However, it still needed to be something pretty large, which made me think about larger geese or swans. The match for a mute swan seemed pretty good:

This is where it gets VERY detailed

So far I've gone from a single bone, to identifying a probable species. But what if I could tell you that from what I found I could tell you a lot more ? For example, what if I could tell from what I found that it was a whooper swan, not a mute swan, and not just any whooper swan, but an Icelandic whooper swan ? A female Icelandic whooper swan ? And that it probably died in the autumn or winter of 1995 ? And that it came to Scotland from Iceland via Ireland then Northern Ireland ? You'd think that was pretty amazing, right ?

And yet I do know all that from what I found, because I've cheated a bit in telling this story. Because remember above I said I found something else with the bone ? Here's how it looked when I first found it !

The bird had been ringed with an identifying number and letter, and after death the ring had remained around the bone ! These rings allow scientists to track migrating birds, and I knew that this ring would offer clues as to how old the bone was.

I googled a bit, and found the CR Birding website, which is a central database of all birds that have been ringed. By searching for a yellow tag with a three digit letters-and-numbers code, this first gave me this search result, which suggested it was a mute swan which had been ringed in the Outer Hebrides in Scotland in 1979-1982, and gave contact details of someone involved in the ringing. I emailed him, and with a bit of investigation, he found it was from a different project where  whooper swans had been ringed in Iceland.

He then asked someone at the Slimbridge wildlife centre centre, who found the exact record for this swan. That showed:

  • This bird was a female whooper swan
  • It was tagged on the 2nd August 1995
  • It was tagged in  Miklavatn, Skagafjordur ,Iceland
  • It was spotted twice after it was tagged
  • The first time was on the 1st October 1995, when it was seen in Co. Donegal in Ireland.
  • Three weeks later it was seen in Co. Londonderry in Northern Ireland.
  • After that it was never seen again, until I found that bone.

That's a journey of about 1,700 miles.

I don't think I have ever found a bone where I've had so much history with it !

So how did it end up in the ice house ?

The only thing that I can be certain about is that it didn't fly in by itself.

The most probable way is that after it died, a gamekeeper threw it in there. But it's impossible to say how it died - which is a shame because whooper swans are schedule 1 protected birds.

This 19 year old bone was an amazing mystery and it is now sitting on my bone shelves. And a BIG thank you to Mr Chris Spray at the University of Dundee (who ringed the swan !) and Kane Brides at the WWT Research Team at Slimbridge !

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Mel said...

How amazing! What a story! :)

minseo said...

it's really interesting...!

Ric said...

Tremendous story. I have always wanted to find a bird ring associated with a skeleton or bone.

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