Wednesday, July 17, 2013

Where do birds come from?

Chiffchaff 'control'

Well, the obvious answer is 'eggs', of course. But after 18 months of bird ringing at home, I'm starting to get some interesting results - from birds I've ringed and which have then gone elsewhere ('controls'), or birds ringed elsewhere which I've then caught at a later date ('recoveries').

Before I went off to Canada, I managed to catch some warblers in a net over a ditch. Two of them were controls and another produced a recovery, which is pretty good going.

I caught a Chiffchaff which had been ringed as a young bird at Rye Meads the previous autumn, as well as the Whitethroat I mentioned in a previous post.

And I just heard about one of the Blackcaps I caught on 20 April. It had reached Rutland Water six days later, and they caught it again four days after that, by which time it had lost a couple of grams in weight so is probably breeding there. Fat is migration fuel, and there's no point carrying it around if you've arrived at your destination!

A couple of other birds have been less fortunate. A female Siskin ended up in the jaws of a cat in Sandy a few weeks later, while a Song Thrush lasted for another seven months before dying in unknown circumstances, also in Sandy.

Here's a map with the best bits so far.

View Bird movements in a larger map