Round two of the Stonechat breeding season on Natural England’s Dersingham Bog NNR for 2018 can probably be summed up as having a sting in the tail…
In the end, only 5 pairs out of 6 produced a second brood and one of those pairs was technically already on a 3rd brood after a 1st brood failure. The timing of this female’s incubation suggested that she had got herself back into breeding condition while still helping to feed her newly fledged young, had built a 3rd nest and laid eggs within 10 days of her 2nd brood fledging… which is very fast, even by Stonechat standards.
We’ve ringed a total of 44 chicks from our first and second broods. In the early years of the project, we’d have been more than happy with such a total but having had two years of very high numbers (95 and 113, respectively), we haven’t quite got out of that expectation and so this is tinged with a slight disappointment.
Our first 2nd brood chicks were ringed in early June and the last 2nd brood young were ringed at the end of June. But at least the brood sizes have been healthy on round two, with 4, 6 and 5 respectively, and with 5 chicks from our early 3rd brood pair. We’ve also switched to our new base colour, metal over dark blue, having used up all our dark green combinations.
The nests of two of the Stonechat pairs were only found at the point where the chicks were being fed, so we ended up finding the nest and ringing them at the same time. This is never ideal as we like to find the nests when they’re at the egg stage, partly as it’s often easier to see bright blue eggs shining up at you from inside a thick heather bush but also that it allows us to better plan volunteer time. If we don’t find a nest area until food is going in, it becomes fairly urgent to find the nest as we’ve no idea how old the chicks will be and they may be at the ringing stage already, as it proved with these two pairs.
The weather during the past couple of months has perhaps at least helped all our breeding birds feed both themselves and their broods more easily, even while the rest of us despaired at the lack of rain and worried over the fire risk to both the reserve and the surrounding countryside. A fire at the nearby Snettisham coastal park which destroyed both valuable habitat for both breeding birds and passage migrants did nothing to calm nerves.
Our Stonechat nests have continued to be in a mix of habitats and in a range of situations – 1 was in low heather right by a busy path, 1 placed right on the ground in low heather but well off the path, 1 high on a slope in very sparse heather with bare ground nearby, and 1 about 20ft off the main path but in the most amazing tunnel in dead bracken we’ve ever seen in well over 100 nests. That one took a great deal of effort to find and it was eventually found with the efforts of 4 volunteers and only then by Roger lying flat on the floor with his long arms buried to shoulder depth in a clump of dead bracken before he found the nest cup – the chicks could not have seen daylight the entire time they were in the nest!
Sadly, the empty territories we started the season with continue to be empty and it also appears that one of our Stonechat females is now missing in action. That pair, which arrived last of all at the start of the season, successfully fledged their first brood of 4 and there was no reason to believe they wouldn’t try for a second brood. However, after seeing the young gradually drift away from the territory, we had intermittent sightings of the female but saw nothing as decisive and helpful as a feeding circuit which would indicate she was on eggs. And now she appears to have vanished entirely and the male is on his own and just loafing about. He’s exhibiting none of the territory defence or activity you’d expect to see if he had a female incubating somewhere and now appears to be in moult, which means it’s game over for this breeding season for him.
Another Stonechat pair which we thought were missing have now reappeared in another part of their territory… and with a fledged brood of unringed juveniles in tow, so we’ve missed a nest entirely! This pair were our first to nest up on the plateau and their first brood fledged in early May. Since then, we’ve failed to find any evidence of a second nest and it’s entirely possible we may have missed a second brood failure. We had some desultory nest building taking place a few weeks ago but nothing came of it and we’d almost decided that pair had also vanished until their reappearance this week. As annoying as it is to have missed a brood (which may technically be their third attempt), it is heartening that we can add at least 3 more juveniles to our overall total for the season.
As we began with very depleted numbers of only 6 pairs on the reserve at the start of the season, we can ill afford to lose any more pairs now. And as timings are very late in general with our nesting attempts, it remains to be seen if any of our remaining Stonechat pairs go on to attempt a 3rd brood.
Dersingham Bog’s other iconic breeding birds have experienced mixed fortunes. Several of our usually occupied Tree Pipit territories remained empty and we had only four pairs of Tree Pipits which managed first broods – two of those we found the nests and monitored success. But we failed to find the nests of the other two Tree Pipit pairs, although we were able to at least confirm breeding when we saw food carrying and fledged young.
One Woodlark pair had two successful broods and although the other usual Woodlark territories have been occupied, proving breeding has been more difficult than usual this year. All the singing Woodlark males, which we hoped indicated that second broods were imminent in June, didn’t really materialise into anything and those pairs appeared to melt away. So the overall picture there remained unclear.
The big success of the summer has been our Nightjars and it’s no exaggeration to say it’s been the year of the Nightjar on Dersingham Bog NNR. Somewhat to our surprise, territory occupation and the numbers of nests for 1st and 2nd broods has been very high. Given we thought Nightjars might have been affected on their migration as much as other species appear to have been and therefore we’d be down on numbers this year, it’s been very heartening that the exact opposite has proved to be the case. We’ve had amazing numbers… the highest number of churring males we’ve had for more than a decade (currently at 25) and the number of nests found so far stands at an amazing 22.