The South West’s owl's are under huge threat after our unseasonably cold spring. Chris Sperring, conservation officer with the Hawk and Owl Trust, finds out how working with farmers and Somerset Wildlife Trust can help avert disaster
March 2012 was warm, with daytime temperatures creeping into the 20s; pretty good for July let alone March. The grass began growing early, and beneath the newly formed blanket of grass a small animal was doing what it does best, breeding.
The field vole (Microtus agrestis) is by far the most important prey species of the barn owl, and in most places the success of barn owls is directly linked to the success of this small mammal. As the warm start to spring continued and field vole numbers increased the response from barn owls across the South West was obvious. Many pairs made the most of the nice weather in March and began nesting, at least a month earlier than normal.
So, back in March 2012 the scene was set for what look like an early breeding season with really good numbers of eggs being laid, and I was already predicting a brilliant barn owl season to come. But as March came to an end the clouds rolled in and the rain began to fall, which continued throughout April.
A short respite in May gave me the chance for some early barn owl nest monitoring, which confirmed big clutches of eggs laid, but rapidly reducing numbers of surviving owlets. Due to the constant rain, adult owls were unable to hunt efficiently as they rely on silent flight, and wet feathers become noisy, which both warns their prey of their presence and interferes with the owls own superb hearing which it needs to hear prey beneath the cover of grass. Less food coming into the nest meant chicks became restless and very hungry. The staged hatching tactic came into play, as the older owlets began eating their younger siblings in order to survive; both by feeding themselves and reducing competition, but even then there simply wasn't enough food coming in. Hungry owlets were venturing out of their nest boxes in desperation, driven by hunger. The result was many, many cases of owlets falling, or being pushed by equally desperate siblings, and either being caught by cats or foxes, or simply starving to death beneath their nest.
This sad scenario was being played out throughout Somerset and North Somerset, with some nests starting with six owlets and ending up fledging one or two. One site in Yatton really highlighted the issue for me, when a pair of barn owls tried breeding twice during 2012, but failed to fledge any young at all.
The Somerset Levels is well known for being one of three strongholds for barn owls in the UK, and is of national importance to the survival of the species, due to young owls produced here moving out to repopulate surrounding areas.
In 2012, however, the Levels had the added catastrophe of prolonged and widespread floods. And, as there is no such thing as an aqua-field vole, barn owls suffered quite badly. Now it wasn't just the young owlets that were dying but the parent birds too.
We saw a huge increase in barn owls being killed by traffic as they moved away from their flooded territories in search of unflooded hunting habitat, and started finding adult birds dead in the nestboxes with their young.
In unflooded areas there was no let-up in the rain throughout the summer months, and whenever there were a few dry days, farmers had to take to their fields en-masse to cut the grass for hay and silage, leaving barn owls who were for once able to get out and hunt, with very little rough grassland hunting habitat left.
With young mortality at the highest level I had ever known and now adult birds dying too, I was finding it hard to be optimistic.
Our only hope as summer drew to an end was that the winter would be kind so that the adult birds would make it through to spring 2013 and have a good breeding season. Of course, this wasn't to be.
The rains continued for a while into the winter but a sense of a drier time ahead soon became apparent. To begin with, the dry periods led to frosts, but nothing drastic and barn owls generally fared well. Yet this winter was to end with a devastating sting in its tail, and one which would continue right into spring. The north-easterly wind blew through late February into March and April. It was bitterly colds. The grass was not growing, so the voles were not breeding.
I began monitoring known nest sites towards the end of April to see whether some of the faithful nests which have been successful for at least 20 years were on course.
Of the ten sites I looked at, only four had barn owls present, and two of those only had just a single bird. Meanwhile, earlier in the year the Somerset Wildlife Trust had set up a webcam in a nest box which had successfully fledged five owlets last year in the hope that visitors to their website could follow the progress of the barn owl family this year.
A male barn owl roosted in the box until the end of March then, like so many others around this time, he failed to return.
This was a pattern that repeated itself in nest box after nest box I visited during late May and June. I could find evidence of barn owl usage, but all signs stopped around March or the beginning of April.
It's now August 2013, and I'm still checking barn owl nests, which I have normally finished doing by now. I have just returned from an 800-acre arable farm which has fantastic, wide grassy margins around the fields. The farmer has eight barn owl boxes, of which six have been successful nest sites in recent years. The margins on this farm are superb and are normally teeming with voles.
But what about the barn owls?
Well, we found no owlets at all. Of the eight boxes checked, three had barn owls in them, and two of those had pairs, with the other having a single female. The positive side was that one of the pairs had a clutch of six eggs – four months late, but a good sign nonetheless, and a good-sized clutch too.
The aim was to secure and increase the population of barn owls in Somerset through giving out one free nest box to every parish in Somerset (335 in all), and to educate and encourage landowners to create rough grassland hunting habitat for barn owls. The people of Somerset have been fantastic; with well over 500 people offering to house the parish barn owl nest boxes.
I was recently interviewed by BBC Radio 4's Farming Today programme, and I used the opportunity to appeal to farmers all over the UK, saying "if you're cutting grass at this moment, please leave an edge of uncut grass. It doesn't matter how wide, as it will all help".
The response was overwhelmingly positive, with lots of farmers offering to do what they could to help. And this is why I am optimistic.
Providing we can make sure there are enough nest sites and enough prey-rich hunting habitat, then the population can bounce back from the devastating year of unseasonable weather that we've just experienced. Barn owls can raise more than one brood in a year if there is enough food for them, so recovery can happen.
Nature conservation is not all doom and gloom, and the barn owl project has shown us yet again that if we all work together there can still be a bright future for British wildlife.