Winter Survival

After a milder winter than last year, we head into the start of the 2019 breeding season at Dersingham Bog in a much better position than we were last year where we were just thankful some of our Stonechats had even managed to survive the double Beasts from the East.

We’ve had 7 territories almost consistently occupied throughout the winter on the NNR and those same territories are now getting a head start in the breeding season.

Bog sunrise0_001As we started to see in previous years, the same pattern repeated itself this winter with some of the territories occupied by the same pair that bred last season and who are now well on with their first brood for this year. Other territories have seen completely new pairs wintering and those too are now also well established as a pair, with some of the females now incubating.

Other territories which were occupied by a new wintering pair have now been ousted by the returning Stonechat pair or single birds from last season. Those are slightly slower to start off this breeding season as they are still establishing or re-establishing their pair bond and the female is busily feeding up to get into breeding condition. And we also have completely new pairs still appearing on site.

Female Piezos Feb 2019

Photo courtesy of Les Bunyan 

We’ve also had a few Stonechats appearing on the reserve through the winter, holding territory for a short period before disappearing again, or being replaced by another new ringed bird. Again, without the colour ringing project, we would not have been aware of these changeovers.


Currently we have 8 occupied territories and there’s plenty of time during April for more to arrive, as has happened in previous seasons. In contrast to last season, we have 8 ringed birds on site, including 1 ringed bird with just a metal ring and no colour rings, so not one of ours…

SC female Boardwalk 2019

Photo courtesy of Les Bunyan

One of the pairs in a core territory at the western end of the reserve is a bizarre mirror image of colour rings – the male being green/metal and green/grey and the female sporting metal/green and grey/green. What are the odds of that combination pairing up?! The male was born in 2017 but has not been reported since fledging, so it’s intriguing to wonder where he’s been in the intervening period.

5 of our ringed birds currently on site were born last season and we’ve had reports of 13 of our 2018 juveniles in total, including reports from other areas, which is a good ratio for a season with just over 50 fledged juveniles in total. 2 of our current males are the 2018 breeding season males back on territory but so far none of our 2018 territory females have returned, but we did have a very low ratio of ringed Stonechats on site last season.

One of our ringed females born last year has returned to her natal territory but overall that tends to be unusual – all our other ringed Stonechats have occupied different territories to where they were born, lessening the odds of them pairing with their own parent if they in turn were still on territory.

SC Phils 1st brood 2019

The milder weather over the winter and, in particular, the unseasonably warm spells in February and March have led to our pairs not only surviving the winter, unlike last year, but starting their breeding cycle early. We already have 4 females incubating, 1 nest building and 3 more pairs established and hopefully also about to start. If this trend continues and the weather is good, we could well have 1st broods fledging by the end of April, so fingers crossed.

Unlike last year, it actually ‘feels’ like spring on the reserve compared to last year, with lots of birdsong and good numbers of Crossbills, Siskin, Redpoll and Brambling around, and increasing numbers of Linnets already in residence and nest-building.

SC Triangle - 1st brood nest 2019None of our work would be possible without the hard-working volunteers on Dersingham Bog who spend each winter clearing scrub to maintain a habitat suitable for ground-nesting birds, and we thank them for their sterling efforts.

We’d also like to welcome 3 new volunteers to our survey team, Alastair, Keith and Les, and we look forward to working as a team throughout the summer on our target species of Stonechat, Woodlark, Nightjar and Tree Pipit. Plenty to keep us all very busy indeed!


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