Today’s afternoon I found some time to collect the pellets that were regurgitated by a Barn Owl Tyto alba that had spent the winter in a wall-mounted nest box in Zwolle, The Netherlands (http://www.timvannus.blogspot.nl/2013/01/barn-owl-tv-zwolle-netherlands.html). After connecting the infra-red camera earlier during the day I noticed the owl was gone, so it was safe for me to climb the ladder and open the box for an inspection. 64 pellets were collected. Based on my observations the owl inhabited the box for at least two months and, assuming that the box was permanently in use, produced about 1.05 pellet there per day. This is considerably less than during previous years, when about 1.3 – 1.5 pellet got produced per day. Additionally, this sample round included a considerable number of small sized pellets, possibly another indication that food had not been abundant during the last couple of months. These pellets will be analyzed by an expert. What exactly the owl was living on during these two winter months will be presented in a later entry.
Most of the pellets had accumulated in the ‘lobby’ of the nest box.
The breeding chamber still contains a Eurasian Jackdaw Corvus monedula nest from the previous year. I noticed there was at least one
jackdaw present near the nest box today.
After being collected, the pellets were put in a plastic bag and frozen.
I am not sure why the owl always abandons this box around this time. I doubt that food shortage is a cause, as I am getting the impression that there currently is a good number of mice present in the garden (and I assume in its surroundings). Therefore I was not completely surprised this evening, when seeing a Barn Owl perched in an apple tree in the same garden, where it was overlooking bird feeders and compost mounds. Now did the jackdaws expel it from its nest box, or did it move in with a mate elsewhere to breed?
No comments:
Post a Comment