5 minute read
Wildlife Chris Sperring MBE
The barn owl season (continued)
IN the August issue of Mendip Times, I started telling you about the barn owl nesting season in 2021 so far. As always with these owls, there’s a twist in the tale, but more on that at the end.
In the last month I’ve managed to witness many owlets who are now starting to fledge. This includes those in our Hawk and Owl Trust Somerset webcam nest box. Prior to fledging I had the opportunity to ring the owlets; ringing is a licensed activity with licences and permits issued by the British Trust for Ornithology.
The ring is placed on the leg of the owlet and has a unique number; the information is only collected when the owl has died, but the information gained does tell us how far the owlets distribute from the parental territory, how long they live and what caused their death.
There’s nothing quite like the pride expressed by a landowner who witnesses the fruit of their conservation efforts as owlets, who are now fully-grown, begin flying with their parents around the farm or countryside.
Whilst checking a nest with a volunteer who’s been helping me since 1985, we come across one that had some very special owlets. Five owlets, a goodsized brood again, but these were all very dark brown. Occasionally I do find darker or even lighter owlets, but to find the entire brood dark brown was something we had not seen in nearly 40 years of monitoring, and so the attention turned towards observing the parent owls.
The male was standard coloured but the female, who was by now roosting away from the noisy owlets, was indeed a very dark phase. After circulating the pictures on social media some people felt that the female was the eastern European race of barn owl (dark breasted barn owl); others thought she might be the African barn owl and a few others thought they could all just be dark colour morphs. Whatever they are, they were the most unusual brood I have ever found.
By August, the season for nest checking starts to wind down and, so far, it’s one which has seen all the hallmarks of the effects of climate change and land use changes. Looking back, this year has once again reaffirmed to me more strongly than ever how weather events shape success and failure. These events don’t just affect the owls but can in fact be seen cascading down through the food chain, from owl to vole and from grass to butterfly and bee, and far beyond.
Talking with an arable farmer just the other week, we compared notes on barn owl success and failure on his farm each year and then putting that alongside his crop yields for those same years. The two sets of information were fascinatingly linked and the binding element was undoubtedly the weather.
After visiting many nests this year, I have found that most sites have had at least two or three owlets but a few sites that could be called traditional have had no barn owls at all. And then there’s the minority of sites which have bucked the trend and had four or more owlets this year.
For an owl that, on average, doesn’t live very long in the wild, the key to success lies in the numbers game: you must breed in your first year and have enough offspring to replace yourself and to offset the high mortality of owlets in their first year, so the more offspring you have then the overall population
By CHRIS SPERRING MBE
stabilises, or even increases.
The pattern of weather and breeding success is quite real; those owls that bred early in the season were the ones that failed or fledged very low numbers of owlets; those that started later, on average had the bigger broods.
With those early season owlets now long distributed, I decided to check on a few of the sites, as I wanted to know what the voles were doing in August after a poor start for this prey species. What I found was a very high population of voles and this was at two of the early breeding barn owl nesting sites. It’s such a shame that these owls literally missed the voles due to the early dry and cold conditions.
That evening, I stayed to watch the adult owls, which should by now be in full moult as their breeding season is effectively over, but what I saw was a male hunting frantically. On catching a vole, he lifted off the ground with the vole in his beak, then in mid-air and flying he transferred the now dead vole to his feet and headed straight towards the nest.
A very special moment for me, as this confirms that there’s a second brood, another lot of owlets to be produced in one calendar year. This site had only two young fledged back in late June and now with the food supply so high, this brood should be much bigger, perhaps even getting this site over the line of the magic number of four owlets. This is nature recovering.
Once again may I say a massive thank you to all the farmers and landowners who call me for advisory visits, then give permission for me to monitor nest sites on their land.