Following the wipeout by the weather of our second broods, with only 8 fledged chicks out of 9 occupied territories, we were hoping that we would end the Stonechat breeding season with a bang and not a whimper. In the end, we had what may be described as a moderate success.
It quickly became apparent that we’d lost two more female Stonechats from our occupied territories on Dersingham Bog NNR. They had still been alive in the immediate aftermath of the bad weather but both these females had suffered failures on both their first and second broods and they simply vanished from their territories and the site, as far as we could tell.
It’s a pattern we’ve seen before. A failure and a success often results in a third attempt but two failures very often mean the breeding season for that female comes to an end. The males were still occupying their territories and singing strongly, but unfortunately no replacement females appeared and both males soon went into moult, which is game over for them for the season.
So we were down to 7 occupied territories from our initial 10, and we ended the season with 6 successful broods, and a minimum of 24 fledged juveniles. The weather was thankfully fairly settled during this final period with a lot of food about, so they were able to bring off broods successfully. We only had 1 brood failure for this final round of nesting attempts where the chicks were predated prior to ringing. The clutches in the nests found were also a respectable 5 eggs each and all hatched.
This brings the total to 61 Stonechat chicks fledged for the 2019 season on Dersingham Bog NNR, which is a very respectable total, considering the number of chicks lost this year, and the fact that we’re still recovering from the effects of the Beast from the East reducing our Stonechat breeding numbers so drastically just a couple of years ago. If the second broods had been successful, that would have added 47 chicks to the final total and we’d have had our second highest ever number of chicks.
The nests were again in a mixture of habitats and situations – 1 in short heather right by the path, 1 in deep heather high up on a considerable slope, 1 in thick short heather on a plateau, 2 way out on the mire and 1 in thick bracken again right by a path.
We also missed ringing the chicks from 3 nests as we miscalculated slightly in anticipating how long it would take the females to recover from the previous bad weather failure. In fact, we underestimated them! Most of the females started building another nest and laying eggs far quicker than we thought possible. In one instance, it turned out to be merely days that one female was on eggs again rather than the couple of weeks we’d thought they might need to recover. And three other females were down on eggs a full week earlier than we’d anticipated they might be – remarkable really given what they’d gone through with the weather and the failure of their second broods. Clearly, Stonechats are tougher than we think sometimes!
So that meant that we were slightly late in starting our nest finding efforts for the third broods. So when finally found, the chicks in 1 nest were already too far advanced to risk ringing and we made a conscious decision not to persist in trying to find 2 other nests. Both were in very difficult positions – one way out on the mire with no clear line of sight at a distance to pin the nest down, and any attempt to stand closer to get the views needed just resulted in too much disturbance for the feeding adults. The other nest was in a smallish but very thick clump of new growth bracken and any attempt to find the nest would have resulted in too much trampling of the vegetation, with all the subsequent risk of making predation easier.
So we decided it was more important that these pairs brought off chicks successfully after both had failed in their second broods than we risk any further disturbance simply to ring them. And, indeed, all 3 nests succeeded and added a minimum of 14 chicks to our final total. We’ve only missed finding 2 nests in the past 4 years out of 97 nests found and over 300 chicks ringed, so it’s the first time we’ve had to make this conscious decision.
It’s been a terrific season and we thank all our survey volunteers, Roger, Irene, Tony, Alastair, Keith and Les, for their sterling efforts this season and for devoting so much time to Dersingham Bog. And we’d like to extend our thanks to our Natural England staff of Tom Bolderstone, Tom Parkes and Nick Davies for all their enthusiastic support and help. Huge thanks also to Sophie Barker of the Norfolk Ornithological Association who stepped in to cover ringing for us when Roger was away for part of the season.
It’s been huge fun and a lot of hard work from everyone, with a lot of highs and unfortunate lows with the big losses. And, as always with Stonechats, it’s been fascinating to learn even more about this charismatic species this year. We’re looking forward to a productive breeding season next year on Dersingham Bog for all our target species of Stonechat, Nightjar, Tree Pipit and Woodlark.