21 May 2016

Barn Owls on the move

We did our first long day of Barn Owl boxes yesterday, checking a swathe of sites from Falmouth across to Godrevy. Around half were occupied, but not all pairs were breeding. It could be that some of these non-breeding birds were just in poorer condition, as the females on eggs were weighing up to 425g whilst those not breeding were more like 310g.

This non-breeding pair were at a site not occupied since we started the project in 2011
Those that were breeding were either on full clutches of eggs on with eggs just hatching, so it was almost perfect timing for the checks.

This site near Fourlanes is our most productive,
with four chicks a one egg left to hatch being a small brood by its own standards!
The birds perhaps laid two more eggs, now abandoned at the back of the box.

Several of the adults were already ringed, which is where the interesting information comes from. Of the three, only one was found where it was ringed, breeding in the same box since we started our monitoring project in 2011. The other two were part of a more interesting story.

A male now breeding near Praze-an-Beeble had originally been ringed as a chick 4km away near Rosewarne just last year. The male of this Rosewarne pair was also ringed, but had actually been ringed as a breeding bird near Gwinear (only 1km distant) last year. We're not sure if he left it was pushed out, but the Gwinear female is sat on a full clutch so has obviously found a new male!

Just to add to the story, the breeding female at Gwinear in 2014 and 2015 had been ringed as a chick near Godrevy in 2012, and a female now breeding at Greenberry Downs had been ringed as a chick at Gwinear in 2014! Are you keeping up...

Some of the movements of birds now breeding in the middle of the project area

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