With the number of Stonechat pairs on Dersingham Bog NNR down to 5 from our original 6, we had hoped that a few of them might attempt a third brood but the season ended not with a bang but with a whimper.
Only 2 of our remaining pairs attempted a third brood, and only one of those was a ‘genuine’ third brood, at our Piezos territory. That female proved to be as prolific a breeder as her mother and produced a brood of 5 chicks for her first brood, then 6 for her second and finally 4 from her third nest.
She was also the female who proved to have a preference for tunnel nests in bracken for her first two nests, again following in the footsteps of her mother and we had no reason to suspect she’d do anything different this time round. But as we were just about to have a whip round for a miner’s helmet for Roger to help him find the nest this time, she surprised us all by choosing a nest in low heather which was almost out in the open, and luckily it proved to be one of the easiest nests to find this season.
The only other third brood pair at our Happy Valley territory had a first brood failure, with the chicks predated at a week old. But that female built a second nest very quickly and brought off 6 chicks in her second brood. It was followed by another quick build of a third nest where she produced 5 young. So technically it was her third attempt but really only 2 broods were successful.
There was also quite a large gap of a month between the ringing of the first of our third broods and the last brood of the season which is unusual. In between, our volunteers spent considerable time trying to work out if the other pairs were going to try for a third brood or not. With one pair, the female vanished and the male went into moult quite quickly. With another pair at a different territory known, the male vanished soon after the second brood fledged and the female was left to feed the fledged youngsters from that brood herself.
The other 2 pairs were a mystery for quite some time and after much volunteer head scratching, it eventually became clear that both pairs had finished for their season. With one pair, the second brood fledged young stayed on their territory and associated with their parents for much longer than usual, even though they were well able to feed themselves by this stage, nearly two months after fledging.
The other pair had an original territory on Phil’s Heath but had fooled us all by bringing off a second brood from a nest we missed entirely in another part of their territory. As it was unclear whether there had been a failure before this latest brood appeared, we could have been looking at technically their third brood. Either way, they didn’t make another attempt.
The weather remained warm and settled throughout with only intermittent rain, so the food supply should have remained good for our birds. So it’s been puzzling why more Stonechat pairs didn’t attempt third broods.
With reduced numbers of Stonechats breeding overall this year, we also didn’t get the usual gathering of fledged juveniles in large creches as we have done in the past two years. And recently the Bog has seemed devoid of juvenile Stonechats entirely so there has already been a dispersal into the surrounding countryside.
So we’d welcome any reports of our birds from both Dersinghan Bog and elsewhere. If the right leg sports a colour ring combination of either metal over dark green or metal over dark blue, it’s one of ours! We’d love to hear where and when they were seen, what the colour ring combinations are and any photos would be very welcome.
So to sum up our season as a whole, we colour-ringed 48 chicks and with a minimum of 3 chicks to add from the nest we missed, that makes a grand total of 51 chicks for this year. A few years ago we’d have been very happy with that total and we can only hope that a mild winter this year allows a good survival rate for our juveniles and we see the return of both existing territory holders next spring and hopefully the occupation of new territories by new birds.
With the help of our dedicated volunteers, we’ll be monitoring the winter occupation of the Stonechat territories on Dersingham Bog and searching for them in surrounding areas such as Snettisham and Roydon. A pattern was beginning to develop over the past few years of some territory holders staying on the reserve all year round, with others leaving and their place being taken during the winter by new pairs. These new pairs were then being ousted by the returning territory holders and we were seeing the establishment of completely new pairs on either existing or new territories.
So this winter holds plenty of interest and fingers crossed for a mild winter in preparation for an exciting 2019 breeding season.