Throughout much of the 2017/2018 winter, events in the Stonechat world on Dersingham Bog (National Nature Reserve) continued in pretty much the same vein as in previous winters, with a combination of occupied and unoccupied territories. As before, we had a mix of new ringed birds taking over from the previous season’s breeding pairs and on some territories, the same breeding pair remained on their territory throughout the winter.
Of the new ringed birds on site, it was heartening to see 8 of the 2017 fledged youngsters pairing up with new partners and occupying existing territories. Two pairs also remained on the Bog from the 2017 breeding season. One pair near the Landfill end had originally bred in 2016 and remained on the same territory throughout that winter and then successfully bred there last year; so it was a continued occupation of one territory spanning more than 18 months. The male of the second pair was our oldest breeding male. Born in 2013, he would enter his fifth year in 2018 (affectionately known to volunteers as ‘white/orange’ for his colour ring combination). So, of the 15 existing territories, we had an encouraging 50% winter occupation.
As we entered our third winter of monitoring site fidelity by our Stonechats, it was following the same pattern as before, with some continued occupation by breeding territories holders but also typically, a new set of youngsters pairing up and taking over territories. And we fully expected it to be Groundhog Day again – that spring would see some of those winter pairs remaining, while others would be ousted by either the returning breeding pairs from the previous year, or by completely new pairings. We weren’t exactly blasé about it, but we were quietly confident we had a handle on what the pattern might be for the third winter on the trot.
However, the weather had other ideas. Since the Stonechat project began in 2012, we’ve been lucky. We’ve not experienced a really bad winter and any poor weather has been limited to short spells. We’ve certainly not had anything like the kind of weather that the two Beasts from the East delivered to not only Dersingham Bog but most of Norfolk and the rest of the UK. Unsurprisingly, it has had a significant effect on the numbers of Stonechat on the Bog and the occurrence of our ringed birds.
Fearing a complete wipeout, our volunteers have been monitoring the site and it has been disheartening to find very few or no Stonechats on the Bog on a number of visits. For a species relying on insects, any prolonged snow cover or ground frost can have a devastating impact on survival. We can only hope that some had found more sheltered habitat elsewhere, but given the extensive nature of the snow coverage and the length of time it lasted, there can’t have been many areas in East Anglia that Stonechats could have fled to in order to survive the harsh weather. In other parts of Norfolk, reserves were reporting similar reductions in numbers of other species such as Cetti’s Warblers and Little Egrets.
As we move from winter into early spring, fortunately the current picture is not as dire as we once feared it might be. We currently have 4 to 5 pairs of Stonechats on site occupying existing territories. Interestingly though, it has been all change in the composition of who remains. We have 4 ringed birds at the moment and none of them are the same as the ringed birds who wintered on site. We also currently have more unringed birds than ringed, so the recent ratio has been reversed. But given how precarious it could have been, we’ll take whatever Stonechats we can get at the moment!
Sadly, our oldest male, White/Orange, may have been a casualty of either his age (4 years and 7 months which is a fair age or a Stonechat) or the weather as he has not been seen since mid-February, just before the bad weather hit. Currently, an unringed male and a new female seem to be occupying his old territory – something he’d never have tolerated if he’d still been on site.
We can but hope that a few more migrant Stonechats will arrive to boost our numbers. Hopefully, we have ‘thrown out’ enough juvenile Stonechats into the surrounding countryside in the past few years (over 250 since the project began), that they will have boosted the Anglian population sufficiently that there is a good supply of replacement Stonechats out there to reinforce the birds on the Bog and plug a few gaps. Only time will tell.
So we now look forward to the approaching breeding season with cautious optimism. By this time last year, we had already confirmed 11 nests but at the moment, we have seen nest building by only 3 pairs. So whatever happens next with our weather, our first broods will already be much later than usual and our numbers much lower. We can but hope for some settled warmer weather into the spring to enable some initial success. We’ll keep you posted!
We’d like to thank one of our new volunteers, Allan Coleby for all his efforts. He helped keep track of territory occupation during the winter and, in particular, the depressing picture post-Beasts from the East. Hopefully, survey work will be more positive for all our volunteers as we move into the breeding season. We’d also like to welcome another new volunteer to the project, Jason Moss (https://twitter.com/mossjason85) of Oriole Birding(https://twitter.com/OrioleBirding) who joins us in time for the breeding season. We look forward to working with both of them and to the Stonechats recovering in numbers again and the project going from strength to strength.