This year we have had quite an expansion in our monitoring of nesting birds in our area: primarily due to Jonny Cooper adding this functionality to his skill sets. All activities are carried out under licence from the BTO. Monitoring of Barn Owls and Stone-curlew are carried out additionally under Schedule 1 licences issued by the BTO on behalf of the appropriate government agency.
Introduction:
Having taken over the monitoring of the Barn Owl boxes in the north west of the county in 2018, following the retirement from doing so by the excellent Paul Darby and his team the previous year, we have since mainly focused on doing so. However, with Rosie joining the Wiltshire Wildlife Trust in 2021, and joining my ringing team soon afterwards, she was instrumental in getting me to focus elsewhere, mainly due to the Swallows nesting in the Trust’s store rooms at Clattinger Farm. Last year we started on monitoring those nests, as well.
Jonny Cooper has helped me with the Barn Owl boxes over the years and this year decided he would like to do his own thing. Primarily monitoring a number of titmouse nest boxes in the Trust reserve at Biss Wood. There had been some nest recording in the wood in both 1989 and 1993, but it was opportunistic, not structured. In order for him to pursue that, Jonny needed to get an endorsement added to his licence, allowing him to process hole / cavity nesting birds. To help him achieve that, we spent a few sessions together at the beginning of the Blue Tit breeding season checking nest boxes together and processing any youngsters ready for ringing. As soon as he passed the threshold for that endorsement we sorted it out and he could carry on independently. At the same time I specified Jonny as an “agent” for Barn Owl box checking. This enables him to focus on the boxes in his area, around the environs of Chippenham and further south, whilst allowing me to focus more on the boxes local to me.
So, to the breeding season:
Barn Owls:
I spent last winter replacing a number of dilapidated owl boxes at my sites and erecting a number of new boxes at new sites in the area, and was hopeful that we would get some benefit from these. Last year was excellent, we checked on 22 boxes. From those we had five successful Barn Owl broods, one brood that was predated at the newly hatched / naked young stage and one complete failure after the three young were predated on the point of fledging, but 23 youngsters were ringed in the season. Also making use of the boxes, we had one brood of three Jackdaw chicks ringed, two broods that fledged before they could be ringed and three broods of Stock Dove, with three ringed from two of the broods, the other fledged whilst I was laid up after back surgery. Essentially, we had 13 boxes that were actively engaged in the breeding process plus there were two other boxes being used for roosting by adult Barn Owls.
This year we had 34 boxes to check. Unfortunately, none of the four additional boxes I put up over the winter attracted any breeding effort, although two were being used as a roost site by adult birds. One of last year’s boxes was unavailable this season. The site had changed hands and I could not find the contact details for the landowner. Some of the boxes Jonny had taken over were active. We had six boxes that successfully fledged young, with a total of 14 chicks ringed. Very different from last year. It is almost certainly the influence of the weather. The previous two years had been excellent vole years. When checking boxes we were finding voles stashed in larders, no shortage of food and we had a single case of brood cannibalism.
This year there was significant brood cannibalism. Two of our earlier broods had four young in each box. They were too small to ring when first looked at. On returning to ring them a few weeks later, we found just two in each of the boxes. Clearly the others had provided food for their siblings. As well as the breeding boxes, at least six were being used by roosting adult birds, with five adult birds caught and ringed during the checking. Six of our boxes were used for nesting by Jackdaws. We ringed six young from two of the broods, the others having fledged before we had the chance to ring them. Six boxes had Stock Doves in occupancy. Two of those produced young that could be ringed and fledged successfully. Of the others, one failed when the nest was predated, and the outcome of two of the other sites could not be accurately ascertained. Three of the boxes had Grey Squirrel dreys in them, one of which did produce a youngster: as I was clearing out the vegetation I heard a slight mewing sound, so stopped what I was doing and found this:
Grey Squirrel, Sciurus carolinensis, Kit
Four of our boxes, two at one site, showed squirrel occupancy.
So, not a great year for Barn Owls. In fact, my most productive site over the last few years had no signs of Barn Owl breeding at all this year. However, we had a total of 18 boxes actively involved in the breeding of various species, plus another six that were being used as roosts by adult Barn Owls. It has to have been a bad vole year!
Hole / Box Nesting Passerines:
The bulk of this work was carried out by Jonny once he had his endorsement approved. We have no comparisons with previous years because it is the first time any of the team have been monitoring these types of nest box. Biss Wood had 21 nest boxes in situ. Not all were boxes set up for titmice: as is often the case, boxes set up for Dormice were also used by them. These boxes produced a total of 82 nestling Blue Tits ringed, plus three of the boxes produced a total of 18 Great Tit nestlings and, the icing on the cake, one of those boxes produced a brood of three Nuthatch nestlings.
Alongside this activity, Jonny took over a number of Tree Sparrow boxes around the Maiden Bradley area: 147 of them spread across five sites. The person who had been monitoring them over the last few years could no longer do so, so Jonny was asked to take them over. He took over later in the season but still managed to produce 50 nestling Tree Sparrows from 10 boxes and one box held a brood of 5 Wrens.
Tree Sparrow, Passer montanus, pulli (photo courtesy of Jonny Cooper)
Open Nesting Passerines:
This was something that I started working on in my local area last year. I expanded my efforts this year, with the help of Rosie and Miranda, and Jonny continued his work further south in the county.
Swallow:
Jonny processed 39 Swallow nestlings from ten nests spread over four sites. There was one nest failure, due to abandonment by the parents, in late July. My team processed 30 nestlings from eight nests spread over two sites. At our Clattinger Farm site we had two nests predated at the egg stage, and one nest in which the eggs were cold and either infertile or nest abandoned.
Swallow, Hirundo rustica, pullus (photo courtesy of Miranda Shirnia)
Blackbird:
Rosie drew my attention to two Blackbird nests at Clattinger. Both were successful, with one producing four, and the other three, nestlings that fledged successfully.
House Sparrow:
For the second year running we had House Sparrow breed successfully in the same nest position as last year in one of the stables at Clattinger Farm. This year we timed it better and managed to ring the three juveniles in the nest.
Robin:
For the first time we got to ring some Robin in the nest. And what a nest! It was inside one of the stables at Clattinger Farm used to store tools, and the nest was built inside one of those plastic boxes in which hardware stores sell screws and nails. They successfully fledged the four young we ringed.
Other:
Andy ringed two Stone Curlew young out on Salisbury Plain, after another season monitoring their breeding efforts. There is a very narrow window for ringing their young, as they become active very soon after hatching.
In Summary:
Clearly the key difference between this year and last is the addition of Jonny’s efforts to the total and, to a lesser extent, the expansion of my teams activities to focus a bit more on nesting birds.
Thanks to all of the landowners who are involved in putting up boxes and allowing us access to carry out our monitoring and ringing work.
Ringing In The Braydon Forest & Beyond 