Back in the marsh

So with a change of tenancy and Covid rules relaxed enough to allow more ringing freedom, three of us ventured into Gunwalloe reedbed for the first non-roost ringing at the site since September 2016. Since that time we've ringed the Swallow roost just twice (in August 2018 and September 2019), so it was great to get back in for some warbler ringing. The site was originally run as a CES (Constant Effort Site) so we hope to restart that in the future.

But as is always the way it has taken a bit of clearance and work to get the reedbed net ride back to a usable condition, including finding the original boardwalk and filling in some gaps. We did still manage to find some poles and guys from years gone by though!

We started early this morning to avoid the heat and with just a small number of nets caught 41 birds before closing up at 9am. Having not ringed at the site for so long it wasn't too surprising to find no local retraps, but we WERE surprised to find two ringed warblers (a Sedge and a Reed), both with AXL rings. The ring sequence did seem familiar and it turns out these were both birds ringed last autumn at Nanjizal (just 30km as the warbler flies), so nice to share some Cornish birds between a breeding site and a migration site.

One of the AXL birds from Nanjizal

Not surprisingly the majority of captures were Sedge and Reed Warblers, but we did also manage a few juvenile Whitethroats and a juvenile Cetti's Warbler. We hope to ring the site more over the autumn so will add updates when we can.

Photogenic Stonechat

Having been photographed as a scruffy young bird at Gunwalloe back in September 2016, we wonder if Z994461 was keen to show of its better side now it looks rather smarter? Local wildlife photographer Terry Thirlaway managed to photograph enough of the ring on a Stonechat in the lighthouse garden at Lizard yesterday to identify it as this same bird - quite an achievement!

So just to celebrate the change from scruffy juvenile to proper grown-up we thought we'd share some pictures here.

Not a bad first morning's netting!

We were joined netting yesterday by a new trainee, working on her PhD with the Cornish Jackdaw Project. Having ringed a heck of a lot of Jackdaws, this was Vic's first session out mist-netting and although we only caught 26 birds we certainly had quality over quantity. So you can't complain when the first non-crow you get to ring is a Stonechat (a scruffy moulting juvenile), closely followed by Tree Pipit, Reed and Sedge Warblers and lastly a Kingfisher!

The rest of the day was spent touring round a few regular haunts for colour-ringed birds, with mixed success. Men-aver beach held our first juvenile Med Gull sighting of the year, ringed in France in July and whilst watching it a Curlew casually walked behind it showing off a combination of red and green rings. It seemed vaguely familiar and was in fact a German-ringed bird first seen in Cornwall on the Roseland peninsula in August 2013 and then at Men-aver beach in August 2014 but not since.

Next stop was Gillan creek, where the only colour-ring on show was one of our own. W:085 was ringed as a chick on the roof of the Marine School in 2015 and not seen since.

Last up was a brief stop-off at Stithians Reservoir, where TBY, ringed on Mullion Island over the summer, was still sat on the island. All before making a brief appearance on BBC Five Live Drive (from 01:56:00) to talk about gull 'attacks' in Scarborough!

Chats and pipits

Just two of us ventured out yesterday to make the most of the calm weather at Gunwalloe. As we've not been able to run the CES this year (due to an inaccessible net ride) we could use 'tape' lures to increase our catch of migrant warblers. It worked!

Our catch of 104 birds was excellent, especially considering most of these came from a single 40' net and a net right out in the open at the edge of the new turnip field. The main species were Whitethroat (19), Sedge Warbler (17) and Chiffchaff (10), though the highlights were three Tree Pipits (the first we've ever caught here) and three Stonechats (two juveniles and an adult male).

Other sessions this weekend have seen the group ringing Spotted Flycatcher and a dozen Grasshopper Warblers at Nanjizal and a very smart Whinchat at Marazion.

Back in the reedbed

The settled weather gave us the chance to get back into the reedbed at Gunwalloe for our second CES visit. It was a bit windier than forecast, but that's Cornwall for you! The session ended with just 17 birds, which is average of 23 for this visit below the (lowest is 15 in 2014 and highest is 33 in 2011).

As per normal the catch was dominated by Reed Warblers, including two birds ringed in 2013. But the oldest birds caught were both ringed back in 2011: a Cetti's Warbler and a Blue Tit. Whilst the latter had been recaught in 2012 and 2013, the Cetti's had avoided recapture since ringing!

Back into the mud for the Gunwalloe CES

The start of our Constant Effort Site season at Gunwalloe is always a slow affair, but this morning's session was even quieter! The new boardwalk in one of the rides did make life rather a lot easier, but the catch of just 12 birds was a bit disappointing... We've actually only managed the first session twice since 2011 as it's normally too windy, but catching 16 birds in 2014 and 19 birds in 2015.

The warbler catch was just four Reeds and three Sedge, but three of these were already ringed, which is where the real value lies. The retrap Sedge we'd ringed in May 2015 (and recaught a month later) and the Reeds were ringed as an adult in 2014 (and recaught twice in 2015) and a juvenile in 2013 (recaught once in 2014 and twice in 2015).

Gunwalloe finally gets some boardwalk!

Many months (or even years!) in the planning, we finally managed to lay some boardwalk at our CES site at Gunwalloe. The boards were ones taken up at College Reservoir to be replaced by newer boards, so we were able to relocate them to our reedbed ringing site. Considering the net-ride was waist deep in mud and water in places, this was no mean feat, but a small group of ringing group regulars suffered the mud to get the job done.

The before and after photo above gives an idea of the vast improvement this will make for accessing the site!

Gunwalloe Swallow in Spain

We tend to ring a lot of Swallows at the roost at Gunwalloe, but the 'return' on these birds is rather small, with very few ever being found or recaught again. In fact, of the 2,007 Swallows ringed in the reedbed, four have been recaught in the reedbed within the same autumn, five have been caught a year after ringing and two have been recaught two years after ringing. Just one has been found dead (in Helston a year after ringing) and we've had two longer-distance movements.

One of these was a bird we ringed in August last year that then headed north, being recaught in Devon 26 days later! A rather more conventional movement has only just come to us via BTO, which was a bird ringed in July 2014 that was then recaught on southward passage in September in Guadalajara, central Spain. This is over 1,000km from Gunwalloe, but this bird obviously had a lot further still to go!

More Mipits on the marsh

With the forecast suggesting no wind today, we took the opportunity to get the triangle out and catch some more Meadow Pipits at Gunwalloe. Unfortunately it wasn't quite as calm as predicted, but we still managed a respectable 61 pipits, along with a scattering of other species.

Highlight for some was a rather fine adult Moorhen, sexed as a female on biometrics.

Meadow Pipit legs and a Poldark encounter

With the wind dropping for a couple of days we took the opportunity to get the Meadow Pipit triangle up for the first time this autumn. We decided on Gunwalloe, as we could ring in the reedbed at the same time, hoping for some late warbler interest.

Over yesterday and today, we handled 134 birds (123 new and 11 retrap) of which 81 were Meadow Pipits. Not too shabby for so early in the autumn, but there were lots of birds passing, but most chose to settle just outside and around the triangle! But it was a good chance for new recruits to get to grips with a nice species with a useful moult pattern.

If you're lucky, you can see the difference in shape of the primary coverts between this adult bird (top)
and a first-year bird (bottom), with the latter being more pointed at the tip.

We also saw a bewildering aray of colours in these birds, with most typically quite bright olive green, but we also saw some rather brown birds, a very grey bird and also one with very distinct orangey flanks and upper breast (but still just Mipits!). It was unusual that these paler birds also had very pink legs and feet, compared to yellow on the greener birds. More on these later in the autumn...

The reedbed nets also produced a few late warblers (two Sedge, four Reed and five Cettis's, including one ringed as an adult in 2011), Stonechat and a smart Kingfisher. A single extra net also did us proud with a Garden Warbler (first ever caught at Gunwalloe) and two Firecrest (also the first caught here!).

We're not used to sharing the overflow car park at Gunwalloe with anyone, especially not at 6 in the morning, so it was a surprise to find it full of vans, lorries and 30+ cars. A quick chat with the security guards later and we found out this was in fact a day of filming for Poldark. We did invite the main man to grab his scythe and clear a new ride, but he declined...

Up-country warblers and a lesson in coverts

We recently received details from the BTO of two warblers caught on our penultimate CES ringing session at Gunwalloe on 16th August, both originating from up-country. Reed Warbler D992026 was ringed at Squire's Down, Dorset, on 11th August so had made the take just five days to make the 230km trip down to Cornwall. It almost certainly did it in one go though, and had also had time to put on some pre-migration weight, fattening from 11.2g to 12.4g in those five days.

An altogether different bird was Sedge Warbler Y941821, ringed at Icklesham, Sussex, on 6th August 2013. You then wonder if this bird chose different autumn migration routes as a juvenile and adult, now coming further west, or was this just coincidence.

The only other ringing of late has been a bit of garden ringing for new trainees, but it's always good to catch some instructive birds. The Blue Tit below very nicely shows the contrast between retained juvenile coverts (dull greeny-blue) and moulted adult-type coverts (blue). This bird had moulted all bar one of its greater coverts, the carpal covert and just the smallest alula feather, so see if you can identify them all in the pic!

Think we'll be able to identify this Dunnock without recatching it!

As an aside, I also dropped into Devoran before high-tide in the evening to check the roosting Curlews, to find two colour-ringed birds. We think the below might be a Scottish bird (the single yellow ring was coded BI) and the other bird looked German, but refused to stand on more than one leg in all the time I was sat watching!

Tent-roosting Swallows

Instead of using our large wooden roosting box, last night we used a pop-up tent to roost some Swallows caught in the reedbed at Gunwalloe. The video below shows them being released at dawn, with all birds successfully dry and safe in the roomy tent.

Although the birds came in to roost very late, of the 350 birds present we caught 76, including a recapture of a bird we ringed in the Gunwalloe roost in July 2014 and also a bird ringed on the Isles of Scilly on 20th August, so heading completely the wrong way in autumn! What was equally surprising was that 24 out of the 76 birds caught were adults (32%), compared to 27 out of 284 (10%) ringed at roost earlier this year.

Final CES of the year

This morning finally saw the end of the CES season at Gunwalloe. With the rides getting wetter and wetter, we're not overly sad to see this last session done! The total of 30 birds seems low but was the highest visit 12 total yet and did include a Kingfisher: only the second ever caught at Gunwalloe.

Whilst we missed three visits mid-season due to poor weather, it was still a very productive year, with more birds caught on visits 10, 11 and 12 than any year since we started in 2011. In fact the year total of 366 birds (315 individuals) was the highest since the outstanding 676 in the first year we ran the site.

Catch totals by visit in the five years of CES at Gunwalloe, with 2015 in red

The change in the annual total is primarily driven by catches of Sedge and Reed Warbler, but the table below also shows interesting changes in some species, in particular the crash in Reed Bunting numbers.

	2011	2012	2013	2014	2015
Sedge Warbler	30/85	33/36	13/64	19/41	35/79
Reed Warbler	88/96	60/48	52/63	43/65	42/61
Blue Tit	23/22	14/8	2/16	4/17	13/30
Wren	5/14	0/9	6/4	5/5	7/14
Cetti's Warbler	3/12	3/0	0/1	1/2	2/1
Reed Bunting	8/13	8/3	2/15	3/3	1/1

The fact that just two Reed Buntings were caught on CES this year seems incredible given the double-figure numbers in every other year.

The most notable recaptures this year included two Blackbirds and a Cetti's Warbler ringed in 2011, and two Wrens and a Dunnock ringed in 2013. For the migrants, we retrapped two Sedge Warblers originally ringed in 2013, but the recapture (and presumably survival) rate of Reed Warblers seems higher, with captures of two Reed Warblers ringed in 2011, one ringed in 2012 and nine ringed in 2013.

Reedbed roost and ruins

With a small break in the weather we finally managed to fit in a CES session at Guwalloe Marsh on Saturday, so while we were there we did a Swallow roost in the reedbed the night before. With well over a thousand Swallows gathering, the birds looked good, the weather looked good and we had our first big Swallow catch of the autumn.

After a long night processing, we ended up with 174 Swallows (inc 14 adults), four Sand Martins and some odds and sods, so a good (if late) start to the hirundine season.

Swallows ready to be processed and put to bed in our roost box

Poor night-time pic, but nice comparison of adult and juvenile Sand Martin

And an even worse photo of them going in the morning!

We followed the roost up by sleeping over by the marsh and then getting up for CES in the morning. The weather was kind for a change and with an extra net the final total of 89 birds was pretty acceptable, including 32 Sedge Warblers and 14 Reed Warblers. Only 69 of these were from standard nets, but this total is our highest ever for Visit 10.

What was apparent was that birds were already fattening up for migration, with several Sedge Warblers carrying lots of fuel: compare the Fat 0 bird weighing 9.1g to the Fat 7 bird weighing 16.7g and you'll get the idea. It was also interesting that it was the adult birds that were the fattest, with the average juvenile weight being 10.8g compared to 13.1g for adults.

Yet another dire photo, this time of a Fat 7 Sedge Warbler

Just to add a bit of culture to the day, we also stopped off to have a nose round the ongoing archaeological dig on the clifftop. The site is a mediaeval settlement and would have been the largest in the Kerrier area, so a bit of a change from the single farm and holiday shop here now! But with some fascinating archaeology on show it was a rather interesting aside...

Apparently these are two walls of an old iron age building

Ringing marathon

Not quite a 26-mile marathon, but a pretty full 24 hours of ringing was had yesterday. In the morning three of us kayak-ed out to Mullion Island to check on the progress of our Great Black-backed Gull chicks. These were, as expected, a bit behind the Looe Island birds, with most chicks being quite small. We ringed a token gesture four birds (and colour-ringed the only large-ish one), with our main ringing visit now planned for the end of the month.

The only chick big enough to ring, sporting one of our improved colour rings

The island also produced a few surprises in the form of an adult Cormorant sporting an orange ring (presumably one of ours from a few years ago), a metal-ringed Shag (presumably local), a pair of Guillemots with a chick (and possibly four pairs of Razorbills) and this Oystercatcher nest.

Later in the day we headed out to Hot Point, Lizard, for our first Storm Petrels of the year. In slightly too windy conditions, we managed 28 birds, including one from the Isles of Scilly and the obligatory bird missing a foot. With a few Manx Shearwaters buzzing round we also switched the tape-lure for a while, but despite five birds coming close none came quite close enough!

With dawn rapidly approaching, we switched location to Gunwalloe to get a pre-dawn net over the new cliff-top Sand Martin colony there. Must have been a bit cold, as birds were rather reluctant to get up, but as dawn arrived we managed to catch 17 birds, including two very fresh juveniles.

Our Sand Martin net was a bit of a Heath Robinson affair...

Juvenile (left) and adult (right) Sand Martins

Reedbeds, Dippers and an interesting Barn Owl movement

With summer vaguely arriving in Cornwall, this week saw us dusting off the mist nets to start the 2015 CES (Constant Effort Site) season at Gunwalloe. This is now the fifth year we've run the scheme, adding to the BTO's national dataset monitoring the breeding performance of a range of species.

The so-called 'dry ride' at Gunwalloe

The first few visits of the season are always a bit quiet, as we are mostly targeting reedbed migrants here, yet to arrive in big numbers. Those that have arrived are busy setting up territory and not flying round the reedbed, so the catch of just 16 birds was expected. This was mostly Reed and Sedge Warblers though, including two of the former ringed in 2013. We also retrapped Reed Warbler Y101100, originally ringed as an adult at Gunwalloe in June 2011 and retrapped seven times since on site. This is even more impressive when you consider this bird has now crossed the Sahara desert at least 10 times!

We are now also just starting the main nestbox checks of the year, with the first chicks ringed this week in the form of our usual Dippers in Idless Woods. We probably missed one brood that fledged quite early, but the second box had two fat chicks (from four eggs) at the perfect size for ringing.

Two Dipper chicks tucked up in their not-so-cosy-looking nest

Last but far from least was another morning spent doing Barn Owl box checks, this time in the west of the county with National Trust ranger Shaun Boyns. Once again birds seemed to be doing pretty well down here, with two pairs already with chicks hatched! One interesting National Trust story was the male in the box at Trevean (an NT farm), which the nestbox camera had shown was ringed. We presumed it was a bird from one of our sites locally, but was in fact a bird that we'd ringed as a chick at Treveal (an NT farm) in 2014. At 8km, this isn't the longest movement we've seen, but it's great to see a bird breeding in its first year, and one we know very well indeed.

GR80993 in his new home at Trevean

GR80993 and two siblings when ringed at Treveal in 2014 (we're not sure who's who though!)

Next stop are Cormorant chicks on Mullion Island tomorrow and hopefully retrieving the remaining GPS data-loggers from our Herring Gulls in St Ives...

Aquatic Warbler recaught in France!

Back in August 2012, we were lucky enough to catch a juvenile Aquatic Warbler on our CES at Gunwalloe, not at the more expected Marazion Marsh where we specifically play 'tape-lures' for them on autumn migration. This was a complete surprise on CES, but not as surprising as today's news...

Y752695 at Gunwalloe in August 2012

We heard just this morning that Y752695 was recaught by French ringers in August 2013 (yes, a year ago...) at Reserve de Briere Sud in western France. This is amazing news and a great link between the migration sites in the western UK and western France. Interestingly, this isn't our first exchange with this reserve, as a Reed Warbler ringed there in August 2010 was recaught by us as a breeding bird at Gunwalloe in  July 2011.

The global population of Aquatic Warblers is just 15,000 pairs, concentrated in eastern Europe (and further east), wintering in sub-Saharan Africa. So although we can put dots on the map linking Cornwall and France, we can also put a big smudge where this bird will have bred in summer 2013...

The BTO's online ringing report has details of just two previous foreign movements of Aquatic Warblers from the UK. These were birds ringed within a day of each other in August 2006, both recaught shortly after in France (one recaught 234km away the next day and another recaught 394km away nine days later!). In fact, 2006 was the last year double-figures of Aquatic Warblers were ringed in the UK (11 birds), with the most since then being 2012 (seven birds), including two in Cornwall.

So the movement of our bird is a really nice addition to the migration picture for this globally endangered bird.

Last CES for 2014

This morning saw three of us running the last CES visit of the year at Gunwalloe. The day dawned pretty cold and wet, so we weren't overly optimistic for a big catch... But in the end, the total of 27 birds was the most we've ever had on the last visit, ranging from 13 to 21 in previous years. This continues the trend of having much better catches late in the season this year...

Dawn over the reedbed at Gunwalloe

Visit totals on CES since 2011

Most of the catch were Sedge Warblers, a surprisingly large number of which were carrying plenty of fat. The heaviest was an adult weighing in at 17.2g, compared to a juvenile of similar size with no fat that weighed 9.4g!

Bit hard to see, but this is a Fat 7 Sedge Warbler (on a scale of 0 to 8)

The difference in wear on flight feathers between juvenile (left)
and adult (right) Sedge Warbler is pretty obvious!

Numbers of Sedge Warbler were the lowest since we started the CES in 2011, with Reed Warblers also pretty low in number. 

	2011	2012	2013	2014
Reed Warbler	184	108	115	110
Sedge Warbler	115	69	77	60
Cetti's Warbler	15	3	1	3
Total catch	533	235	257	226

Apart from Sedge and Reed Warblers, the only other bird of note was a juvenile Cetti's Warbler: a species that hasn't done too well at Gunwalloe over the last few years. Compare numbers on the CES in 2001 to those the last three years!

Finally, thanks to everyone that's helped out with the CES this year and it's been pretty grim at times, especially on the so-called 'wet ride' which turned into more of a swamp than anything else over the last few visits...

The notorious Gunwalloe 'wet ride'

Dusky Swallow, odd Reed Bunting and more big gulls

The weather has been kind the last few days, and the forecast is looking good for the next few days, so we've been busy taking advantage to get mist nets up. A quick couple of mornings last week at Marazion caught over 120 birds, including this very smart Cuckoo.

In preparation for our latest CES visit this morning, we put up nets last night and managed to catch 25 Swallows in the process. There's always one rusty bird in these catches that makes a change, but I don't think I've seen one quite this dusky before.

Excuse the poor photo, but it was late...

The actual CES itself this morning was half-decent for a change. The average catch on Visit 10 is just 35 birds, so our total of 57 this morning was very respectable. Unsurprisingly most were Reed and Sedge Warblers, although 11 Blue Tits were a bit unwelcome! One more unusual bird was a very dark-headed Reed Bunting. Despite having a rather black head, it didn't have any real white collar, and the presence of an obvious brood patch confirmed this was a female. It was actually a retrap, first ringed as a juvenile in July last year. Whilst you do sometimes see female birds taking on male characteristics the older they get (female Blackbirds turning black for example), this bird was probably just very worn, with the dark feather bases showing through on the head.

Very dark (or worn) first-summer female Reed Bunting

Talking of wear, also check out the comparison here between a fresh juvenile Reed Warbler and a worn adult. The one will have had its flight feathers for a month, the other for perhaps five or six months.

The last few days have also seen a good gathering of big gulls at Lizard Point, and we've managed to read a whole host of colour rings, including birds from Norway, NE Scotland, France and local SW birds.

Black 42M (top left) from Normandy, France, and Yellow T:013 (bottom right) from NE Scotland

White L:BS3 (top left) from Looe Island, Cornwall, and Green K03 (bottom right) from Normandy, France

Thanks to Dave Jones for the reedbed photos and Terry Thirlaway for the gull photos.