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.