Following our thankfully milder winter and with Stonechat occupation of Dersingham Bog NNR at a good level, hopes were that our 2019 breeding season would get off to a good start and so it proved.
As mentioned in a previous blog, with 8 territories occupied at the end of the winter, some of those pairs remained on site for the spring, while new pairs arrived and some Stonechats from last year’s season returned to their 2018 territories, ousting the winter incumbents and some took up new territories entirely. So we started our first round of breeding attempts with 10 pairs, and with 3 new survey volunteers to add to our survey team, spirits were high.
With little poor weather through April, our Stonechat pairs breeding attempts progressed well and as we now come to the end of that first round of nesting attempts, we’re delighted to report that we’ve ringed 25 chicks, with a further 4 chicks to add to the total from a pair that snuck off a brood right under our collective noses!
The clutches have been fairly small, with more than usual having just 4 eggs as opposed to the usual 5 and we’ve also had the usual spread of some unhatched eggs within those clutches. We’ve had 5 broods of 4 chicks, with 1 brood of 3 and 1 brood of 2 chicks. So we might have expected more chicks from a first round attempt with such a good number as 10 pairs but at least it’s a good start.
All our pairs nested early for their first broods, which bodes well for them attempting a second brood, and possibly even a third if the weather cooperates. Unusually, and unlike previous years, our first brood pairs have not been synched with their timings, which at least has helped spread the volunteer workload more evenly. We’ve had some pairs on eggs while other clutches were already hatched or with chicks nearly ready to fledge. The pair that managed to sneak a first brood off unseen must have started incubating in mid-March which is incredibly early.
We’ve had two failures, one predated on young chicks and one clutch of five eggs which didn’t hatch. That female sat it out to the bitter end, incubating for well over the usual two week period before abandoning the clutch. The failure on chicks also seems to have triggered a change in female. Whether she was predated as well or she just abandoned her partner and the territory after she lost the chicks is unclear, but either way, the male seems to have attracted another female relatively quickly. He’s busy displaying and establishing the pair bond, so hopefully his new female will begin a nesting attempt soon. As far as we can tell, there have been no other partner changes, although our volunteer survey team is in the process of confirming that – back to their regular pastime of peering at Stonechat legs!
At the moment, we have a range of fledged juveniles of varying ages scattered across the site – some just fledged and hiding in the undergrowth as they complete their plumage, and still being actively fed by the parents. Others are well-developed and flying well, with only the occasional bout of feeding by the parents. Sometimes it’s more a case of the juveniles chasing after the parents for food rather than the adults actively seeking the youngsters out. So it won’t be long before these youngsters disperse from their natal territories but many are likely to remain on the reserve for a while yet.
The nests were in a range of habitats and situations, as we’ve come to expect from our Stonechats. What is typical, as we’re learning, is the habit of choosing nest sites close to paths or tracks. Of our 9 found nests for this first round, 7 were close to the main track and, in some instances, literally within a couple of feet of it and, therefore, very vulnerable to disturbance and predation. Yet these are large territories so the females could easily choose a more secluded and undisturbed site.
The nests close to the path had no common theme in the type of nests or vegetation chosen. 5 were in heather, with 2 nests at ground level and 3 a foot or so off the ground in the middle of sparse heather bushes. The other 2 were in dead bracken, one tucked under a ‘shelf’ on the lip of the main path and very vulnerable, and the other was in dead bracken right on the ground by the path. This was the nest predated on chicks, so its exposed position might also have contributed to its vulnerability to ground predation.
We’ve already seen nest-building from some of our second brood pairs, while at least 2 pairs have only just fledged their first brood young. So we can expect the second broods to be equally spread out in terms of timing. Several of our core territories remain empty so there is still room for more occupation if extra birds arrive and at the time of writing, 2 pairs seem to have moved to their neighbouring territories. It’s unclear why as both pairs were successful on their initial sites and each territory is considered prime Stonechat ‘real estate’ so we’ll have to see how they progress next time round.
Our Woodlarks have not done so well so far this season. We’ve only one active pair, as far as we can judge, and while these were successful with their first brood, bringing off 2 youngsters with 2 unhatched eggs left in the nest, their second brood has just failed, with the eggs being predated. Other than lone singing males on two other territories, there don’t seem to be any more active pairs and some of our previously occupied territories now appear empty.
So far we have 8 singing male Tree Pipits establishing territories on the reserve and we’re now starting to get to grips with how many are paired and work will soon start to find those which may already be on eggs. As we begin the preparations for the first of our reserve-wide Nightjar surveys this week, with Tree Pipits now on site, efforts being made to find any Woodlark we might have missed, and our second brood Stonechats about to get underway, one thing Dersingham Bog NNR doesn’t lack is variety!