Sunday, 16 June 2013

Food Availability

This first year female was found roosting in one of our most prolific breeding sites at Lach Dennis last night. Although she was in superb condition she showed no signs of being ready to breed this year.
The barn owl box contained lots of pellets and it was noticeable that they were all somewhat smaller than usual. Analysis of the contents of a typical pellet revealed that more shrews than field voles are being taken and the relative sizes of the bones revealed that some of these are younger animals.

Three shrew skulls are on the left (note the diagnostic red on the teeth below) and a couple of short tailed field voles on the right (zigzag teeth patterns). It suggests that although this bird is finding food to hunt, it is not doing so in sufficient quantity or quality to prepare her for breeding yet.


  1. Superb pictures, thanks for posting. Is there any reason why they're not feeding so well this year, was the late winter a factor? Kind regards, Brian. (From Shropshire, not a million miles away!)

    1. Hi Brian,
      I think that this is one of a number of factors. The deluge of wet weather over the last year has flooded out many vole runs in our local fields.
      Vole populations are subject to cyclical crashes (the last one being in 2008) and during these times the owls choose not to breed. My checks on Kestrels this year have also revealed very few breeding attempts taking place. They too are also reliant upon the availability of short-tailed field voles as prey.