Nightjars 2019 Survey Season

Once again, we’ve enjoyed a fascinating season with our Nightjars on Dersingham Bog NNR. After 25 churring males and 23 nests in 2018, we hoped this season would be just as productive and so it proved, with similar figures to last year.

Our evening surveys produced a minimum total of 23 separate churring males holding territory and we had a minimum of 16 pairs. We found 22 nests, which breaks down as 14 first broods and 8 second broods, and a mix of 15 twins and 7 single chicks were spread across all our nests.

NJ Phils 1st brood-2019This year we resumed ringing our Nightjar chicks and managed to ring 27, with a minimum of 3 chicks we missed to add to the total. These were from two 1st brood nests, as we later had fledged juveniles on one territory when we found the 2nd brood nest, and on another nest a well-grown juvenile was roosting with the female as she incubated her second clutch.

Based on the locations of some of the 2nd brood nests, we probably missed at least 4 more 1st brood nests and similarly, a minimum of 4 more 2nd brood nests. Unusually, some territories which have been consistently occupied for years were empty this season so it’ll be interesting if that pattern continues next year.

Our first nest was found in late May and our last discovered in mid-August so we had the usual spread of breeding attempts throughout the season. We didn’t experience the long hot spell that characterised last summer but the bad weather in early June which wiped out our 2nd brood Stonechats didn’t appear to affect our Nightjars too much. Although we’ll never know if some of the 1st brood nests we didn’t find perhaps failed as a result of the weather.

Sheperds East NJ eggs 1st brood 2019We suffered 8 known failures – 5 at the chick stage and 3 on eggs, including clutches where the females disappeared. It’s an unfortunately high ratio to lose more than a third of the nests found. Predation must play a significant part, although for some nests abandoned at the egg stage, we found the eggs still untouched in those nests even weeks later.

As is typical with Nightjars, the nest areas chosen were quite varied. While the nest site itself is the usual bare scrape, what surrounds it can vary hugely. Some nests were in dense cover, typically heather, where you had to almost stand on top of the nest before you could see it. Others were sparse bracken, sometimes on the edge but often in the middle of thick growth. One nest was on wetter ground, on a raised area with a rhododendron stump but in the middle of very boggy ground.

IMG_0679aOther nests were out in the open, some with virtually no cover at all, and at least one of those was a failure. Open nest areas made it easier to check the progress of the growing chicks from a distance without disturbance but it presumably also made it easier for predators. Some nests were in a clearing provided by birch sapling stumps or by clusters of bramble bushes in the middle of heather. One common factor with a lot of our Nightjar nests is their liking for sites against stumps or cut wood, which lends a helping hand to their incredible camouflage. There were also a surprising mix of nests on the level plateaux but also on slopes, where only a small area of level ground on a slope can be sufficient for a nest site.

Distances between nest sites was also quite interesting to map. As is usual, 1st and 2nd brood nests can be quite close to one another – literally within 10m in one case. And different pairs can nest in fairly close proximity – either at opposite ends of the same plateau or in one case, 2 nests were either side of the main path, probably about 50m apart.

Another interesting aspect of our Nightjar pairs is the consistency of nest site locations, which perhaps hints at it being the same female from year to year? One nest was not only in the same bracken clump but on exactly the same spot within that bracken. Other nests we can almost predict where they’ll be within a few yards, which certainly lessens the effort needed if we can walk straight to an area and find them with minimal searching.

NJ Little Nose 1st brood - odd egg 2019We also had something we’ve never experienced before. One of our 1st brood clutches consisted of an egg of normal size and colour but the second egg was smaller and completely white. There was lots of speculation if this would even be viable (or even what would emerge!) but a normal sized Nightjar chick with equally normal plumage eventually hatched, grew at the normal rate and fledged successfully, along with its sibling. Interestingly, what we presumed was the same female then went on to produce 2 normal eggs for her 2nd clutch.

Also unusual was that some of our 1st brood chicks were being brooded by the male a lot earlier than usual. We usually find 1st brood chicks are around 10-14 days old before the male takes over brooding duties while the female starts incubating her 2nd clutch. This year when we were ringing 1st brood chicks, we found  males brooding when the chicks were just over a week old.

This year we also started swabbing the chicks for a DNA sample and collecting faecal samples. This is an exciting project and forms part of a wider project across the country to look at Nightjars’ diet, as well as looking at the DNA linkages between different populations of Nightjar.

nj 1

Photo courtesy of Les Bunyan

A variety of nest-finding techniques were used this season and we want to do further trials next year so we have as many options available as possible. As usual, monthly evening surveys were conducted reserve-wide, along with individual volunteers making extra evening visits so we could target our nest-finding more effectively. Historical knowledge of past nest sites was also very helpful and enabled us to carry out targeted nest-finding with considerable success, which minimises both volunteer effort and disturbance. Later in the season we started to use a thermal camera and it has potential, although it also has its limitations in the wide variety of terrain we have on Dersingham Bog, and more practice will be needed to refine how best to use it.

Roping is a traditional nest-finding technique for Nightjars and it’s very successful and we found many of our nests using this technique. It became an in-joke at one point that wherever Les was on the rope line, the Nightjar nest would inevitably be found in front of him! He even managed to find one nest just walking back to the car park one day, minus rope…

NJ chicks Phils 1st brood 2019But roping does take a lot of effort and time, and needs a lot of bodies to cover the ground more effectively, and roping slopes is really hard work but the camaraderie of group nest-finding can also be a lot of fun and very satisfying when it works. Some abiding memories include a double rope line of more than 10 people covering a lot of ground one day and watching Tony walk into a hollow completely out of sight (no mean feat given his height) and also Les disappearing into head high bracken. We figured as long as the rope didn’t go slack and the bracken kept moving, we hadn’t lost him…

Blind luck also plays a part in Nightjar nest-finding, as it always does. We found several nests just by walking from one part of the reserve to another, or when working on our Stonechats. One memorable occasion, having checked a Nightjar nest with Sophie, hoping to ring the chicks but finding it had failed, we walked off the heath and promptly stumbled on the female brooding her 2nd clutch of eggs within 50m, and that nest went on to be successful.

Huge thanks, as  always, to our survey volunteer team of Roger, Irene, Alastair, Tony, Keith and Les, and equal thanks to our work party volunteers and NE staff, Tom and Nick, who pitched in with the roping. Everyone put in a huge amount of effort this season and we’re very grateful for all their time and enthusiasm. And once again, we’d like to extend our thanks to Sophie Barker of the Norfolk Ornithological Association who gave up so much of her time to come along and ring Nightjar chicks while Roger was away.

IMG_0673aIt’s always immensely satisfying to follow the fortunes of Nightjars from their arrival on the reserve, spending time experiencing their behaviour and unique calls on the evening surveys, through to finding and monitoring their nests, to helping with the ringing. Watching the chicks grow from literally a ball of fluff that can fit in the palm of your hand to almost the size of the adults in barely 3 weeks, and seeing the development of their amazing plumage, will never be anything less than a privilege.

NJ female

Photo courtesy of Les Bunyan

It’s heartening that Dersingham Bog NNR remains such a stronghold for breeding Nightjars in Norfolk and what we learn from each season helps to inform management work across the site. It’s been an immensely enjoyable season and, as always, we continue to learn more each year as we work on such an incredible bird.

By Alastair Steele & Irene Boston & thanks to Les Bunyan for the photos

 

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Stonechats Round 3 – Fizzling Out

Following the wipeout by the weather of our second broods, with only 8 fledged chicks out of 9 occupied territories, we were hoping that we would end the Stonechat breeding season with a bang and not a whimper. In the end, we had what may be described as a moderate success.

It quickly became apparent that we’d lost two more female Stonechats from our occupied territories on Dersingham Bog NNR. They had still been alive in the immediate aftermath of the bad weather but both these females had suffered failures on both their first and second broods and they simply vanished from their territories and the site, as far as we could tell.

It’s a pattern we’ve seen before. A failure and a success often results in a third attempt but two failures very often mean the breeding season for that female comes to an end. The males were still occupying their territories and singing strongly, but unfortunately no replacement females appeared and both males soon went into moult, which is game over for them for the season.

Long Nose 1st brood nest 2019So we were down to 7 occupied territories from our initial 10, and we ended the season with 6 successful broods, and a minimum of 24 fledged juveniles. The weather was thankfully fairly settled during this final period with a lot of food about, so they were able to bring off broods successfully. We only had 1 brood failure for this final round of nesting attempts where the chicks were predated prior to ringing. The clutches in the nests found were also a respectable 5 eggs each and all hatched.

SC Long Nose 2-3 days old first brood nest 2019This brings the total to 61 Stonechat chicks fledged for the 2019 season on Dersingham Bog NNR, which is a very respectable total, considering the number of chicks lost this year, and the fact that we’re still recovering from the effects of the Beast from the East reducing our Stonechat breeding numbers so drastically just a couple of years ago. If the second broods had been successful, that would have added 47 chicks to the final total and we’d have had our second highest ever number of chicks.

Flat Nose Sth - SC 2nd brood 2019The nests were again in a mixture of habitats and situations – 1 in short heather right by the path, 1 in deep heather high up on a considerable slope, 1 in thick short heather on a plateau, 2 way out on the mire and 1 in thick bracken again right by a path.

We also missed ringing the chicks from 3 nests as we miscalculated slightly in anticipating how long it would take the females to recover from the previous bad weather failure. In fact, we underestimated them! Most of the females started building another nest and laying eggs far quicker than we thought possible. In one instance, it turned out to be merely days that one female was on eggs again rather than the couple of weeks we’d thought they might need to recover. And three other females were down on eggs a full week earlier than we’d anticipated they might be – remarkable really given what they’d gone through with the weather and the failure of their second broods. Clearly, Stonechats are tougher than we think sometimes!

BogSo that meant that we were slightly late in starting our nest finding efforts for the third broods. So when finally found, the chicks in 1 nest were already too far advanced to risk ringing and we made a conscious decision not to persist in trying to find 2 other nests. Both were in very difficult positions – one way out on the mire with no clear line of sight at a distance to pin the nest down, and any attempt to stand closer to get the views needed just resulted in too much disturbance for the feeding adults. The other nest was in a smallish but very thick clump of new growth bracken and any attempt to find the nest would have resulted in too much trampling of the vegetation, with all the subsequent risk of making predation easier.

So we decided it was more important that these pairs brought off chicks successfully after both had failed in their second broods than we risk any further disturbance simply to ring them. And, indeed, all 3 nests succeeded and added a minimum of 14 chicks to our final total. We’ve only missed finding 2 nests in the past 4 years out of 97 nests found and over 300 chicks ringed, so it’s the first time we’ve had to make this conscious decision.

It’s been a terrific season and we thank all our survey volunteers, Roger, Irene, Tony, Alastair, Keith and Les, for their sterling efforts this season and for devoting so much time to Dersingham Bog. And we’d like to extend our thanks to our Natural England staff of Tom Bolderstone, Tom Parkes and Nick Davies for all their enthusiastic support and help. Huge thanks also to Sophie Barker of the Norfolk Ornithological Association who stepped in to cover ringing for us when Roger was away for part of the season.

Boardwalk SC chicks 3rd brood 2019It’s been huge fun and a lot of hard work from everyone, with a lot of highs and unfortunate lows with the big losses. And, as always with Stonechats, it’s been fascinating to learn even more about this charismatic species this year. We’re looking forward to a productive breeding season next year on Dersingham Bog for all our target species of Stonechat, Nightjar, Tree Pipit and Woodlark.

 

 

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Stonechats – Round 2 Wipeout

Following the successful fledging of 29 chicks from our first brood Stonechats on Dersingham Bog NNR, we hoped it would be followed with further success for our second broods. Typically, these broods tend to produce the highest numbers, both in terms of clutches laid, eggs hatched and fledged young, as the weather is usually more consistent and a lot warmer, with more food available for both adults and young.

Happy Valley - SC 6 eggs 2nd brood nest 2019As our volunteers steadily found all the second nests for our active Stonechat pairs, it soon became apparent that the females had laid some pretty large clutches. Of our 9 active pairs, 7 had laid clutches of 6 eggs, with the remainder on 5 eggs. We’ve had clutches of 6 eggs before but it’s usually only been 1 or 2 pairs at a time, so to have such a high proportion of big clutches right throughout the reserve was very promising.

As the incubation progressed to hatching, we were pleased to find that nearly all of the big clutches hatched in full, with very few unhatched eggs among them. So we planned the ringing excited at the thought that this time round we might have a record brood total, reserve-wide, with the possibility of 52 chicks due to be ringed.

Then the weather intervened.

In common with other areas of the country, Norfolk experienced a spell of horrendous weather in early June, where it rained heavily and consistently over several days. There was a brief break in the bad weather which only lasted a day, but then we had two days where it rained heavily and non-stop all day and night and well into the following day. It was also cold, with a strong wind blowing from the north. And nearly all our broods were around a week old when the bad weather hit, so they were all at a very vulnerable stage.

So when we were due to carry out the ringing later that same week, we were braced for some failures but it was worse than we feared. It was almost a complete wipeout… or washout might be a better description. Of 47 chicks due to be ringed that day, we had only 2 survivors. It was a grim day, with volunteers finding a mixture of dead chicks either in the nest or in the surrounding vegetation and territories ominously quiet with adults also absent. Some of us had seen it before and we all know it’s all part of the natural cycle, but it’s impossible to be indifferent when you experience something like that.

Judging by the age of the chicks when they died and counting back, we worked out that it was the weather on those final two days of the bad weather spell that did the damage… the cold and the wet and the struggle to find food finally too much for the chicks and adults.

SC chicks 9 days old Pylon 2019(1)In some good news, we had 6 chicks still alive in one of the nests that was slightly later than the others in timing. We worked out later that those chicks must have been hatching during those two days of the worst weather, so the female must have somehow sat it out.

It may have been helped by the aspect of her nest. Quite by chance she had built a nest in thick dead bracken with an almost impenetrable screen of it to the northern side of the nest and most of the bad weather was hammering in from the north. So hopefully, she was helped by the nest vegetation protecting both her and the chicks from the worst of the weather. When we checked the nest that day to see if they were still alive, we found both the nest and chicks warm and dry.

Piezos SC nest site 2019 cropShe seems to be a remarkable female Stonechat all round though as one of our volunteers on a Nightjar survey a few nights later saw her still catching moths by the light of the moon at nearly midnight. When we came to ring those chicks a week later, it was great to see such healthy thriving chicks – all 6 of them, and they’ve since fledged successfully.

The volunteers spent the week after the bad weather working out if the adult Stonechats were still alive and it looks like we may have lost another female as there’s been no sign of her since, although the male is still on territory and singing intermittently. Since then, another female also seems to have left her territory. She was still present the week after the rain but has not been seen recently and the male there now seems to be alone.

Both of these territories had first brood failures as well, one on eggs and the other on chicks, so two failures may well have prompted the females to end their breeding season. Even in a good seasons without failures, not all pairs go on to make 3 breeding attempts anyway.

Little Nose SC 2nd brood nest 2019The range of nests that failed were in a mixture of vegetation, from high up in thick heather to low down on the ground in grass tussocks, or in dead bracken which was both on dry banks or out on the wet mire. As is the pattern, 5 of the nests were close to paths in a mix of vegetation and at varying heights, both at ground level and in two cases, at head height in dead bracken with new growth above it.

There were several nests that faced north so were completely open to the weather. Some nests also had a relatively open aspect directly above them so the rain would effectively have drained down the vegetation straight into the nests, the angle of the approach to the nests almost acting like a funnel for the water, so some nests were thoroughly saturated. They really didn’t stand a chance in such conditions and the weather was just bad timing all round. A week or so later and more chicks might well have survived.

So out of a possible 52 chicks from this round of second broods on Dersingham Bog NNR, we ended up with only 8 fledged young – a very disappointing result given what might have been. We suspect our Tree Pipits’ first broods suffered similarly from the bad weather arriving at the wrong time, with most of the males now singing again and with only one pair seen food carrying. Our Nightjars seem to have weathered the storm, literally, and we are now up to 16 nests found, with a mixture of first and second broods (we’ll report on our so far terrific Nightjar season at a later date).

In the meantime, we look forward to our 3rd broods of Stonechats and some of our pairs are already on eggs, with our volunteers working hard to find the remaining nests from our 6 active pairs. So fingers crossed, we can make the most of the rest of the season.

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Stonechat season – round one

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.

SC female Boardwalk 2019

Photo Les Bunyan

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!

SC Phils 1st brood 2019The 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.

SC Predated Tranquil nest 2019We’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!

SC chicks 9 days old Pylon 2019(1)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.

Landfill West SC 1st brood 2019The 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.

 

SC-Happy Valley 1st nest 2019The 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.

WL nest 2nd brood 2019 Sheperds - predated (1)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!

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Stonechats – it’s all in the voice…

This is a good time of year for experiencing the considerable variety of Stonechat vocalisations. Both males and females utter a range of alarm and contact calls and song during the breeding season which mean specific things at different times of the cycle. Combined with visual clues gleaned from their behaviour, these vocalisations can help work out what stage of the breeding cycle each pair are at.

At the moment on Dersingham Bog NNR, we’re hearing just about every possible variation as our Stonechat pairs are at different stages of their nesting attempts, with some still on eggs, some with hatched young and some already with fledged juveniles.

Stonechat Roydon Les Bunyan

Photo courtesy of Les Bunyan

SONG
Only the male Stonechat sings and the peak song period is March and April. It can then cease, apart from brief peaks just prior to the start of each new nesting attempt but declines when the young hatch. Males can sing in good weather throughout the day and not necessarily at dawn. The frequency of song also depends on the nearness of neighbouring territories, with boundary disputes often triggering a burst of song from either male.

Song is also given by the male Stonechat as a distraction technique when observers are approaching a nest area, or are inadvertently sitting or standing too close, as a kind of ‘look at me’ technique by the male, or a distraction to allow the female to leave the nest unobserved. There is also a subdued version of the main song used in a similar fashion as a distraction.

CALLS
Both males and females utter a variety of calls, chiefly used as a warning or distraction. The warning call is usually a short, clear single note whit – often uttered by the male when observers are approaching the nest area and may be used to warn the female not to leave the nest. This is often followed by the male flying away from the nest area, leaving the female still sitting. It can also be used to warn young in the nest and recently fledged young to remain silent.

The distraction call is a harsh chack. Uttered by both sexes but more often by the male, it’s frequently heard when the incubating female is on a feeding circuit if observers are too close to the nest and may be preventing her from returning to it. This call is often accompanied by short flights and wing and tail flicking to try and distract observers away from the nest and towards the calling adult.

SC female unringed Stefan Oscarsson Thornham Feb 2019AThe whit call is most often used during incubation and the chacking call comes more into play when the young are hatched and being fed in the nest. All the calls increase in volume and frequency the closer an observer is to the nest and decline as the person moves away.

The whit call can also used by the male to call the incubating or brooding female from the nest for a feeding circuit if he perceives no threat – i.e. an observer is far enough from the nest area; although she may also be reluctant to leave the nest if the young are close to hatching. However, when the young have hatched, she can also leave the nest immediately upon hearing the call, so observing behaviour as well as listening to the calls becomes crucial at this stage in order to work out what’s going on.

There is also a much harsher double chack with a click-click note at the end which is given loudly and constantly by both sexes if observers are near a nest with well-grown young or recently fledged young. This is also accompanied by both parents trying to distract with wing and tail flicking and flying towards the observer and then away again, to try and ‘tempt’ the intruder away.

SC-Flat Nose Nth Male + 1st brood juv 2017 Benno Zeelte

Adult male with recently fledged juvenile. Photo courtesy of Benno Zeelte

Calls increase in volume and frequency as the young grow, reaching a peak when the young are near to fledging and continue after they fledge, particularly in their first week out of the nest. While the male continues to feed the young after fledging and will alarm if a person is near, the calls will gradually decrease as another nesting attempt begins when the female begins building another nest and the young from the previous brood leave their natal area or are chased off by the male. Fledged young also have a hoarser chack call which they give as begging calls for food or in response to an intruder; it’s a subtly different note from the adult’s chack call.

Each pair is different though and some we’ve found are very tolerant of a fairly close approach to the nest before they will alarm, regardless of what stage they’re at in the breeding cycle, while others will alarm when observers are some distance from the nest area. Pairs can also alarm when a ground predator is present or corvids but they rarely seem to alarm in response to the presence of birds of prey.

Both sexes can utter a variety of other interesting calls at different times, including a brief hoarse rattling krrrrr which is used in song flights or territorial defence and the thin seeseeseeseesee call is usually given by the female. Nestlings can sometimes be heard calling shree shree shree shree, although in practice it can be difficult to hear until a person is standing right over the nest or it’s a call they can give sometimes when they’re handled.

SC male Tranquil valley unringed2This only covers a fraction of the vocalisations Stonechats can produce. The song is especially varied and given in a variety of circumstances. We’ve just covered the ones which are helpful to our volunteers in their survey work, particularly in the nest-finding process, and helping to judge the relevant stage of the breeding cycle so volunteer time and effort can be planned more effectively. There’s a whole other article in trying to cover the display and song patterns and behaviour of this charismatic chat.

If you’re curious to listen to some of the vocalisations, Xeno Canto is quite a good resource for examples of the different calls and songs – https://www.xeno-canto.org/species/Saxicola-rubicola

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Stonechats elsewhere

As well our ringed Stonechats wintering on the reserve, we’ve also received some interesting sightings this winter of our ringed birds from elsewhere in Norfolk, with both birds born last season on Dersingham Bog NNR being reported and the first sighting of a bird born several years ago but not reported since. Birds have been seen at Heacham, Deepdale Marsh, Roydon Common and Holme Bird Observatory.

Of our crop of 48 ringed juveniles last season, so far 18 ringed birds have been reported to us, which is a good reporting ratio as well as a survival rate for the juveniles; no doubt helped by the milder winter this year. It’s interesting to speculate how many other Stonechats from last year’s ringed crop have survived and just not yet been seen or reported to us.

Of those 17 reported Stonechats, 9 are now on territory on Dersingham Bog NNR, with 1 more ringed male seen in mid-winter but who no longer seems to be around. Of those reported ringed birds, 10 were male and 6 were female.

SC juv Happy Valley -2nd brood Deepdale Marsh Mark AndrewsOne male was been tracked this winter from Deepdale Marsh along the Norfolk coast and is now on territory at Thornham, where he is paired with a female and appears to be breeding. That male was first seen at Deepdale last September just a couple of months after he fledged from a second brood of one of our core territories, so a decent distance for a juvenile who’s not long left the natal site.

SC juv Bryants 2nd brood Deepdale Marsh Mark AndrewsInterestingly, at the same time he was seen at Deepdale, there was another of our ringed males at the same site. While the second male was also born last season, it was from a different territory on Dersingham Bog and these males fledged a month apart. Amazing then how they ended up at the same spot at the same time.

Another of our ringed males has since appeared at Holme where he is similarly paired with an unringed female and currently feeding first brood young (thanks to Pete Bangs for this most recent photo).

One ringed male was seen by one of our survey volunteers, Les Bunyan, on Roydon Common and it’s the first report of this bird since he fledged from Dersingham Bog in 2015. It’s entirely possible he’s been at Roydon for a while but perhaps just not reported?

Male SC Winterton March 2019 Ringed - photo by Dave RobertsA tantalising glimpse of a ringed male at Winterton by Dave Roberts was probably one of our birds too, although the ring combination couldn’t quite be nailed down but hopefully if the bird remains at that site and breeds, someone may yet get a better view of its ring combination.

Snettisham Coastal Park seems to be a good ‘gathering ground’ for Stonechats in general, both in the winter and in the breeding season, and Ray Roche reported a ringed female seen there in April this year, so it’ll be interesting to see if she pairs up and breeds.

We’re very grateful to everyone for reporting their sightings and for the cracking photos submitted and for allowing us to use them on the website and our Twitter feed. We can only plead for more sightings really – we’d love to hear from anyone who sees a ringed Stonechat, even if it’s not one of ours! We’d especially like to hear of any which are successfully breeding, both in Norfolk and elsewhere.

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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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Life as a survey volunteer on Dersingham Bog…

As the survey work on Dersingham Bog National Nature Reserve goes from strength to strength and the Stonechat project continues to be such a success, it’s an appropriate time to pay tribute to our hard working volunteers and say thanks to Roger, Irene, Tony, Molly, Jason and Allan for all their efforts this year.

SAM_3753We are still very actively recruiting volunteers for our survey work on the reserve and would very much like to hear from anyone interested in joining us as we plan next year’s survey work. The main focus of our survey work is to survey, monitor, nest-find, and ring where appropriate, our iconic Dersingham Bog species of Stonechat, Nightjar, Woodlark and Tree Pipit.

But rather than us extolling the virtues of volunteering on the Bog and how rewarding it can be, it’s easier to let one of our volunteers, Tony, sell it for us…NJ 2 chicks-Kestrel box site 183

Having recently retired into the area, and being an enthusiastic birder, I was keen to explore local opportunities to volunteer.

One interesting piece of work that caught my eye as I searched the internet was that of the NW Norfolk Stonechats group on the Natural England Reserve National Nature Reserve of Dersingham Bog. Their website provided fascinating information about Stonechat activity on the Reserve, together with an invitation to get involved if you could spare some time.

I made contact with the group and with impressive speed, I was receiving a comprehensive briefing from Natural England in their office in Wolferton on their work on the Reserve, together with the necessary Health and Safety stuff.  No mention at all of midges, I recall!

Juv Stonechat1A week later I was on the Reserve to meet Roger and Irene, two current and experienced volunteers, and begin my initiation into the fascinating world of Stonechats. The project aims to survey, nest find and colour-ring breeding Stonechats on the NNR and record adults and juveniles outside the breeding season. The project also gives insights on whether individual birds are site faithful, as well as generating data on productivity and fledgling survival.

Over the next few weeks, my initial concern about knowing very little about the target species, and being worried about doing the wrong thing at the wrong time, was replaced by growing confidence and a genuine interest in these characterful birds. This personal development of mine was solely down to my two ‘mentors’ who between them had many years of knowledge and experience to share. And share they did! In such a positive way that I was soon hooked and really enjoying the hours spent observing Stonechat.

Triangle - SC 2nd nest 20181I was taught the art of observing and interpreting Stonechat behaviour, and encouraged to offer opinions and have a go at finding a nest or two. It’s a great feeling when it all comes together and a nest is located, young observed in the nest, the young are ringed and then successfully fledge!

And then things got even better when I was invited to take part in a Nightjar Survey on the Reserve. What an enthralling experience that was!

NJ + 2 chicks 15 days-RLine 201813Again, I was fortunate enough to team up with Irene, who is both passionate about Nightjars and very happy to share her comprehensive knowledge on the subject with a complete beginner (who would have thought Nightjar equalled churring?!). What an amazing bird!

Species nest finding and monitoring sessions on the Bog have continued and every visit brings something new – with learning different or unusual behaviours for both Stonechat and Nightjar. With plenty of encouragement and guidance, I have been fortunate enough to have helped find both Stonechat and Nightjar nests. What a thrill!

Although the season is coming to an end, I look forward to helping out with the monitoring of existing and prospective Stonechat territories over the winter on Dersingham Bog NNR, and hope that this year our winter is kinder to the birds than it was last year.

TP 1st brood Phils Heath 2018_001And I haven’t even mentioned how delightful it was to wander around the Reserve accompanied by the song of both Woodlark and Tree Pipit. Nests for both species were found this season, and survey work on the reserve next year will include both these species and I look forward to learning more about these two fascinating birds. All the nest monitoring and colour-ringing on Dersingham Bog aims to inform the management work on the reserve and enable reserve staff to plan future work for the benefit of all these iconic heathland species.

If you have even a small interest in nature, with a bias towards birds, I recommend without hesitation getting involved with a group like NW Norfolk Stonechats. They are a very welcoming and knowledgeable bunch, and the work is fascinating too. And it’s good for you and the birds!

RS + IB Triangle May 20183_001If anyone would be interested in finding out more about the volunteering opportunities for survey work on Dersingham Bog, please get in touch. northwestnorfolkstonechats@gmail.com We’d love to hear from you.

Survey experience is not essential as training can be given. Although if, like Tony, you have already participated in survey work in the past, that would be welcome. Experience with the 4 species involved is also not essential as training on Stonechat, Nightjar, Woodlark and Tree Pipits is all part of the support given to our volunteers. Contributions from ringers would also be welcome, to back up and assist Roger.

So please contact us for more details or help spread the word that we’re recruiting!

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Round three… fizzling out.

With the number of Stonechat pairs on Dersingham Bog NNR down to 5 from our original 6, we had hoped that a few of them might attempt a third brood but the season ended not with a bang but with a whimper.

Only 2 of our remaining pairs attempted a third brood, and only one of those was a ‘genuine’ third brood, at our Piezos territory. That female proved to be as prolific a breeder as her mother and produced a brood of 5 chicks for her first brood, then 6 for her second and finally 4 from her third nest.

Happy Valley SC 3rd brood 20181_001She was also the female who proved to have a preference for tunnel nests in bracken for her first two nests, again following in the footsteps of her mother and we had no reason to suspect she’d do anything different this time round. But as we were just about to have a whip round for a miner’s helmet for Roger to help him find the nest this time, she surprised us all by choosing a nest in low heather which was almost out in the open, and luckily it proved to be one of the easiest nests to find this season.

Molly - Happy Valley July 20181_001The only other third brood pair at our Happy Valley territory had a first brood failure, with the chicks predated at a week old. But that female built a second nest very quickly and brought off 6 chicks in her second brood. It was followed by another quick build of a third nest where she produced 5 young. So technically it was her third attempt but really only 2 broods were successful.

SC male Tranquil valley unringed1There was also quite a large gap of a month between the ringing of the first of our third broods and the last brood of the season which is unusual. In between, our volunteers spent considerable time trying to work out if the other pairs were going to try for a third brood or not. With one pair, the female vanished and the male went into moult quite quickly. With another pair at a different territory known, the male vanished soon after the second brood fledged and the female was left to feed the fledged youngsters from that brood herself.

The other 2 pairs were a mystery for quite some time and after much volunteer head scratching, it eventually became clear that both pairs had finished for their season. With one pair, the second brood fledged young stayed on their territory and associated with their parents for much longer than usual, even though they were well able to feed themselves by this stage, nearly two months after fledging.

The other pair had an original territory on Phil’s Heath but had fooled us all by bringing off a second brood from a nest we missed entirely in another part of their territory. As it was unclear whether there had been a failure before this latest brood appeared, we could have been looking at technically their third brood. Either way, they didn’t make another attempt.

BogThe weather remained warm and settled throughout with only intermittent rain, so the food supply should have remained good for our birds. So it’s been puzzling why more Stonechat pairs didn’t attempt third broods.

With reduced numbers of Stonechats breeding overall this year, we also didn’t get the usual gathering of fledged juveniles in large creches as we have done in the past two years. And recently the Bog has seemed devoid of juvenile Stonechats entirely so there has already been a dispersal into the surrounding countryside.

So we’d welcome any reports of our birds from both Dersinghan Bog and elsewhere. If the right leg sports a colour ring combination of either metal over dark green or metal over dark blue, it’s one of ours! We’d love to hear where and when they were seen, what the colour ring combinations are and any photos would be very welcome.

So to sum up our season as a whole, we colour-ringed 48 chicks and with a minimum of 3 chicks to add from the nest we missed, that makes a grand total of 51 chicks for this year. A few years ago we’d have been very happy with that total and we can only hope that a mild winter this year allows a good survival rate for our juveniles and we see the return of both existing territory holders next spring and hopefully the occupation of new territories by new birds.

Long Ponds from Foxhole_001With the help of our dedicated volunteers, we’ll be monitoring the winter occupation of the Stonechat territories on Dersingham Bog and searching for them in surrounding areas such as Snettisham and Roydon. A pattern was beginning to develop over the past few years of some territory holders staying on the reserve all year round, with others leaving and their place being taken during the winter by new pairs. These new pairs were then being ousted by the returning territory holders and we were seeing the establishment of completely new pairs on either existing or new territories.

So this winter holds plenty of interest and fingers crossed for a mild winter in preparation for an exciting 2019 breeding season.

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Our matriach’s legacy…

We mentioned in our last blog about a nest that was unusual even by Stonechat standards… a nest on the floor in dead bracken but so well hidden it was literally in a tunnel. This Dersingham Bog territory (known as the Piezos) has always been renowned for tunnel nests. The current resident female’s first nest was also in a tunnel but a more standard one, partway up a clump of dead bracken which was at least visible when standing right over it.

Piezos SC 1st brood 2018-JasonThe past occupant of this territory was also notorious for preferring to build nests in tunnels. She was our oldest ringed female, born in 2013 and last seen in early 2017. Over the 3 years she nested on the reserve, she had many of our volunteers scratching their heads trying to find her nests and used up many hours of volunteer time. She had a habit of choosing either vertical tunnels, ‘trap door’ tunnels, horizontal ones, ones at right angles, tunnels in bracken or in grass tussocks and even in dead vegetation out on the mire, and it wasn’t long before she became affectionately and fairly obviously christened ‘the tunneller’, (although unfortunately we don’t have a photograph of her).

And it’s no wonder that the current female Stonechat on this territory also has tunnelling tendencies as she’s the tunneller’s daughter, born in 2016 in a second brood in that season. So it’s in the genes! She nested last year on Dersingham Bog NNR in a neighbouring territory but this year moved to her natal territory and has produced 2 broods so far this season and is currently incubating a third.

Piezos 3rd brood SC 2017Other progeny of the original female have also exhibited a preference for tunnel nests and it’s an interesting trait and something which we wouldn’t be aware of but for the CR project.

Not only was our original ‘tunneller’ our oldest ringed female but she has proved to be our most prolific. She would regularly be the first to start breeding each season and would bring off 3 successful broods in a season, each with high brood sizes and with different partners in the three seasons she bred between 2014 and 2016.

Either directly through her direct progeny or through her progeny’s progeny, she was responsible for 116 juvenile Stonechats, which is an amazing number and accounts for a third of our total number of juveniles produced on Dersingham Bog since the project began in 2012. Many of the new pairs occupying the reserve in the last few years have been her progeny, which in turn have produced juveniles of their own which have then dispersed into the Stonechat population.

SC juv Henry PageAnd those juveniles are just the ones we know about. At least 2 of her juveniles have been reported from a range of other locations, such as Snettisham Coastal Park and Winterton, and those in turn may also have bred successfully. So the final total of chicks which carry her genes may be even higher. We also missed a couple of her broods during the time she bred on the reserve. So this one female surely must have played an important role in Dersingham Bog becoming almost like a nursery for our locally recovering Stonechat population… or at least it was until the Beasts from the East devastated our numbers.

To flesh out the figures a little, our matriarch produced 24 young while breeding on Dersingham Bog NNR in just three seasons. And of those 24 juveniles, 9 Stonechats of her direct progeny returned to breed and set up their own territories in 2015, with 2 reported breeding elsewhere in Norfolk, and those 9 now have a large number of descendants from the last two seasons.

Piezos-SC 2nd brood nest 20180_001It’s a remarkable legacy for one small passerine and one that was only breeding for 3 years but it goes to show quite effectively how much of an impact a bird like this can have. She has formed the core of our Stonechat breeding population and the breeding picture on Dersingham Bog NNR over the past few years may have been very different without her.

 

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