Though the factors affecting the Barn Owls probably include:
- 2012 started off as a promising short-tailed vole year, but the wet and cold summer/autumn hit them hard and very few were found cached.
- Barn owls bred well to start with in 2012, but the poor weather and food availability hit them hard with lots of chick stage failures. Some boxes had the same female fail twice and in others two different females failed, and chick weights were low.
- The poor weather continued into the autumn & winter/spring which caused very poor first winter survival. To maybe show this, in 2012 I processed 19 first summer barn owls, this year it was 5. In 2011 & 2012, I ringed c80 pulli. Not hellishly scientific, but a crude measure showing a 75% drop in first winter survival between 2011-12 and 2012-13.
- The winter extended well into spring this year. The BTO had 3-4 times the usual recovery rate of dead Barn Owls and these, unusually, were mainly experienced adults who, for lack of food, left their territories and got killed on the roadside. In a good year they would have been on eggs by April.
- Birds that survived to breed in 2013, either tried early on and mostly failed or appear to have delayed and are having some success now.
Sorry if this sounds pessimistic! A mild winter (please) and a good vole year will allow the Barn Owls to come back from this very poor year for them.