Round one of the Stonechat breeding season on Dersingham Bog for 2018 can probably be summed up as… less than we hoped but more than we feared.
After the late blast of winter weather, we headed into spring with just 5 pairs of Stonechats on territory but we’ve managed to boost that to 6, with one pair arriving nearly a month later than usual. This was way below last year’s total of 13 pairs but given that some areas of Norfolk have reported a complete wipeout of their Stonechat numbers, we’ve been very lucky.
All our pairs have been staggered in their breeding timings as well, with some still on eggs while others were already feeding chicks. This at least meant it was easier to plan our volunteer effort and any bad weather striking the reserve didn’t hit all the pairs at a vulnerable time and cause big losses, which happened last season with our first broods when May’s bad weather wiped out 50% of our first broods.
Our total number of chicks from first broods this year was just 18. Our first chicks were ringed at the beginning of May and our 6th pair’s first brood ringed at the end of that month, with the chicks from the other pairs ringed at roughly weekly intervals in between.
Our first pair to nest produced only 2 chicks but laid 5 eggs, which seems to be a common occurrence on this particular territory. Given that this is the third pair to nest on this heath, it’s curious that each time the different females have laid 5 eggs but only 2 have hatched and subsequently fledged. Our next brood on another territory produced 3 chicks but only 2 fledged, with the runt dying in the nest.
Fortunately, this was followed by a healthy brood of 5 chicks from a regularly occupied territory, and then 4 chicks from another core territory. Our first brood failure was of 4 chicks which were predated from the nest before they were ringed but the final pair which arrived late managed to produce 4 chicks.
Even with these reduced numbers, we’ve managed to use up almost all our dark green colour-ringed combinations and we’ve switched now to dark blue for the rest of this season.
We’ve also been quite lucky with the weather so far this spring. Whilst we’ve had spells of cold northerly winds and sometimes foggy conditions, we haven’t had prolonged or heavy spells of rain, and this has also been balanced with very warm settled spells of sunshine and light winds. Sometimes we seem to have experienced both winter and summer within the same week.
The nests have been in a mixture of habitats – 4 in heather, 1 in bracken and 1 in a mixture of sparse heather in a grass tussock, and the range of nest sites chosen has been equally varied. 4 have been right on the floor, 1 high and deep in a tunnel in dead bracken, and 1 well hidden in the middle of a substantial heather bush.
As our successful pairs start their second nests, the pair which experienced a first brood failure have already nested again, the female building another nest within a week. She laid 6 eggs and 5 healthy chicks were ringed this week.
So over the next couple of weeks, we can hopefully see the remaining 5 pairs beginning to incubate their second broods and our volunteers will be busy nest finding, as well as keeping an eye on the currently empty territories to see if any new pairs sneak in.
Other areas of Norfolk seem equally affected by low Stonechat numbers. While there are 2 pairs in Snettisham Coastal Park and 1 pair on Scolt Head Island, our volunteers haven’t found Stonechat pairs in areas where they’ve bred regularly over the past few years, such as Brancaster, Thornham, the Drift, Dersingham, and Hunstanton Golf Course and we hear reports of other areas of the Norfolk coast being similarly affected.
For our other Bog specialties the breeding picture is mixed. Our Tree Pipits only have 4 territories occupied this year, with 2 nests found so far. More worryingly, 4 other Tree Pipit territories which are nearly always occupied remain empty. Our Tree Pipits were also late arriving back and it seems to have been a similar picture with other summer migrants, both on the reserve and elsewhere either late arriving or not arriving at all. Other reserves and birders are reporting late arrivals or low numbers of summer migrants like Whinchat, Garden Warbler and Reed Warbler. Presumably the storms in Europe during migration have impacted how many have been able to return?
Nightjar survey work has only just begun so we should gain a clearer picture of their numbers soon but so far we have 4 nests with 3 other females found.
With our Woodlarks, 1 pair produced 4 young and 2 other territories seemed occupied in early spring but although no first nests were found, those males are now singing again so we can assume second brood attempts are imminent. Interestingly, 2 territories which we thought were empty early in the season are now occupied. So whether this is a late occupation or they’ve managed to get first broods off under our noses isn’t clear.
The timing for our Stonechat breeding attempts has also been affected, with most of the first broods being several weeks later than usual compared to previous years. We can confidently expect each pair to attempt a second brood but how many go on to make a third breeding attempt remains to be seen.