The Suffolk Community Barn Owl Project was established about a decade ago in order to raise the population of this beautiful owl in our county by the provision of nest boxes. By the end of 2012 more than 1,200 boxes were in position and in that year almost one-third of the boxes were used by Barn Owls for roosting or nesting. The Project has certainly been successful in increasing Barn Owl numbers and many landowners and farmers have assisted by allowing boxes to be sited on their land.
However, in 2013 the owls have suffered a really poor breeding season due to a combination of very poor spring weather and a lack of their main food, bank and short-tailed voles.
From late February through to mid-April, East Anglia was battered by bitterly cold north-east and east winds blowing all the way from Siberia. This affected many things, including crops growing in the fields, and most of the summer migrants, such as Swallows, were late arriving. Barn Owls appear to have been affected quite severely, with some found dead during and after the cold spell while many that survived have failed to breed, probably because the females were not in good enough condition to lay a clutch of eggs.
This disaster appears to have been compounded by a lack of their main food supply. Barn owls feed almost exclusively on voles and vole populations are known to be very variable. They usually build up their numbers over several years and then crash down to a low level and 2013 has been a “crash” year.
I checked eight local boxes, with Sandy Jackson and Mike Walker from Ixworth, on June 21st. One box contained one small chick and another box had a female present with a clutch of five eggs. In another box I found a long dead adult owl and while one or two adults were present in three of the other boxes there were no eggs or young. Subsequently I checked nine boxes or sites on Elveden Estate, known to be frequented by Barn Owls, without finding a single egg or chick. Two sites at Sapiston yielded a brood of two chicks in a natural site that I was able to ring, with the other site, a box, containing a pair but no progeny.
A later visit on July 25th to the box referred to above that contained a female and five eggs revealed four chicks. I ringed the two larger birds but when we returned on August 12th, hoping to ring the two smaller chicks, they had disappeared, quite possibly eaten by their larger siblings as that sometimes happens when food is scarce. The two big chicks fledged in early September, but then on 19th of that month I received a phone call to say that one of the young had been found dead. The box is in a large garden that adjoins Pakenham Fen and the dead bird was in the garden. When I checked the body it weighed only 191 grams, (a healthy Barn Owl weighs 300/350 grams), so it had clearly starved. Exactly the same happened at Lackford Lakes where two young from a brood of three were found dead and very underweight. Other ringers and box monitors throughout Suffolk have reported a similar very poor season.
So the Suffolk Barn Owls have certainly taken a knock this summer. Provided we get a run of milder winters and springs they should be able to recover their numbers, but a repeat of this spring’s awful weather would be most unwelcome both for the owls and us.
By Malcolm Wright