10 May 2017

Glow in the dark owls

Yesterday saw us doing our first round of Barn Owl nestbox checks, covering just 13 sites on the Lizard (but almost 100 miles of driving). It looks like this will be a good year, perhaps following on from a very dry spring. Most of the boxes we checked had clutches of five or six eggs, several of which were just in the process of hatching, with many boxes also having very full 'larders' of rodent prey. Quite a few of these sites were new ones for 2017 as well, so with occupancy rates very high this is again an encouraging sign for a productive season.

Newly-hatched chicks still dwarfed by some of the prey stashed for them!

It is always useful for us to catch the adults in the boxes, as we can track the repeated breeding efforts of birds across years, but also any birds caught can be returned to the box, where they invariably settle back down straight away to continue incubating or brooding. We've also been looking at using a small UV torch to better see distinctions between old and new flight feathers in adult birds, which can help in ageing them. We've not quite mastered this yet, but the photo below shows the pattern on one bird, with two new moulted flight feathers fluorescing pink against the surrounding older feathers. ore info on this technique can be found online (http://www.bioone.org/doi/abs/10.1676/09-125.1).

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