Sunday, 21 August 2011

Some Barn Owls are busier than others . . .

I've been doing some checking for second breeding attempts by the Barn Owls, as well as late breeders. The premise for this is predicated by the first brood having been born by no later than mid-April, and that the female BO showed no signs of wing moult when trapped as if they were in moult it indicates they're most likely done breeding. This reduces the number of boxes to go back to significantly, but it's also worth checking boxes close by as they will second clutch were the male's been roosting.

Anyway, this was Duncan and I's mission when we set off for the Vale of Belvoir last Friday. First, we went to two boxes at Normanton where a pair of BOs had flew from one of them in early June to see if they were now breeding. We went to that field box first and trapped a first summer male BO, that had been ringed as a chick near Flawborough last year. As it was not going through post-breeding wing moult, we wondered if the female had gone down in the box in the adjacent garden. This proved right, and we trapped a ringed female and ringed 3 of the 5 chicks that were big enough to ring, and 5 S-T Fields, 2 Field Mice and 1 shrew were cached.

Now, if you're still awake, this is where it gets really interesting. We had caught the first summer female on 3 chicks that were 3-4 weeks old on the 7 June in a nest box about 2 km away. So, not only has she bred twice, but must have been laying the second clutch while her mate was still feeding the first brood. Double broods is not uncommon with BOs, but I've only once before in 2007 at Farndon proved this rapid turn round before. Going by the cache size the male BO is obviously good at hunting. I'm left wondering if he's one of the birds that left the Normanton box in June, may be paired up with his second 'wife' who he may or may or not have bred with. All a bit Jeremy Kyle really.

Jim

1 comment:

  1. PS Forgot to say that I've never seen a second brood bigger than the first before.

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