Further to Dave's post on the Demog Blog on early breeding, I thought it might be worth mentioning that whilst doing maintenance on our Kestrel and Tawny Owl boxes today (20/1/2014), we came across a Tawny Owl which was probably sitting on eggs. Luckily we hadn't made a lot of noise putting the ladder up and so managed to see her without causing her to be flushed from the box. We revisited in the evening and recorded a clutch of two.
|A slow growing 39 day-old Tawny Owl chick in 2012- Mike Price|
Checking 50 boxes each spring (in fact mostly plastic barrels) makes the start of the season seem to come around very quickly. We usually have an occupation level of about 40%. The last two years have seen this rate plummet, and 2013 saw just 10% of the boxes occupied with just one pair being successful in fledging two young. We recorded a few other successful pairs at lower elevation in natural sites. One nest hole contained seven Magpie wings and a pair of male Sparrowhawk wings.
We usually don't revisit the boxes after the maintenance until the beginning/middle of April, when we often find eggs or small young (Birdfacts suggests early March to early May for laying).
|Tawny Owl submissions to the Nest Record Scheme show a peak in clutch initiation (laying of the first egg) during March and April|
Another thing of interest this year has been the lack of Grey Squirrel dreys in the boxes. Of the 30 boxes visited so far, we have come across just one squirrel in a summer drey which is very unusual. I can recall one box last year containing 10 non-breeding squirrels.
|Tawny Owl 'nest box'. You can see the damage that squirrels can do to the barrels in the above picture - Mike Price|
Peak District Raptor Monitoring Group