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).

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

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...

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.

Another poor CES visit and pasty-snatching gulls

A couple of us did the postponed CES this morning at Gunwalloe and despite the mud, sweat and much cursing, managed a paltry 23 birds. This doesn't exactly compare well with the 132 bids on the same visit in 2011, but oddly does beat the nine birds from last year. Most of this morning's catch were Reed Warblers (16, including two birds ringed in 2011), but a juvenile Whitethroat and an adult Swallow added a bit of interest. Finally (!!) we also caught our first Cetti's Warbler of the year; a bird we originally ringed as an adult back in 2011 and not recaught since. Having said that, one of the 2011 Reed Warblers hadn't been caught since ringing either...

On the gull front, last week was a bit manic, variously ringing 'pasty-snatching' gulls in St Ives (10 adults), rooftop gulls in Falmouth (nine chicks) and Great Black-backed Gulls on both Mullion Island (16 chicks) and Looe Island (74 chicks). The latter isn't our project, but read more about it on the Tamar Wildlife site. All of these gulls also received shiny new colour rings, so ones to keep an eye for in the future.

Blue W:186, caught with the help of an ice cream, turned out to be the
regular bird that holds territory at Rod's Deckchairs in St Ives

Sunny day on Mullion Island ringing gull chicks (Daisy Salmon)

We've also just seen the final county ringing totals on the BTO's online ringing report and it's interesting to compare with group totals. This is more a reflection of the lack of ringers in Cornwall, but in 2013 the group ringed ALL of the Storm Petrel (235), Cormorant (11), Shag (6), Kittiwake (10), Dipper (3), Stonechat (15), Wheatear (3) and Linnet (45) ringed in the county! Blowing our own trumpet a bit, we also ringed more than 90% of Meadow Pipit (392), Goldfinch (314) and Reed Bunting (48) in the county. So again a big thanks to everyone who helped out or let us ring on their land in 2013.

At the county level, more Great Black-backed Gulls (80) and Jackdaws (480) were ringed in Cornwall in 2013 than any other county, withe other notable totals for Rook (62, beaten only by Sussex) and Yellow-browed Warbler (19), losing out to the Northern Isles: Orkney (29) and Shetland (31).

Dire CES and our first Kittiwake chick

The last few days have been busy as ever, including a very poor CES visit to Gunwalloe. The graph below shows how our catches in the reedbed have been pretty poor this year (shown in black) in comparison to the previous three and our recent session was barely any better, with 17 birds only a slight improvement on last year. The catch was mostly Reed Warblers, but here's hoping it'll pick up soon...

On a slightly better note, a quick visit to Rinsey yesterday found our first Kittiwake chick of the year. Not so good news was the fact that there are very few pairs in the zawn and that two birds that were on eggs have now lost them...

I do wonder if the apparent decline in Kittiwake numbers has something to do with the concurrent increase in the number of pairs of Herring Gulls in the zawn. From only a couple of pairs a few years ago there are now as many as 15 pairs, which must have some impact on the Kittiwakes.

Herring Gulls are much earlier breeders than Kittiwakes,
with pairs already with well-grown young

We've also recently met up with Shaun Boyns who runs the National Trust's West Cornwall Barn Owl Project and hopefully in the future we'll be able to work with Shaun to monitor their nestboxes. The project is just taking off now, with 18 new boxes going up this year, so this would be an exciting addition to our network of sites.

Three Barn Owl chicks at the National Trust offices at Treveal

Dire CES and productive owls

At the weekend we managed to cover both our third CES visit at Gunwalloe and also a bunch of Barn Owl boxes across the south/west of the county, with varying success.

Conditions for CES were pretty perfect, but the catch of just 11 birds (inc five Reed Warblers) is the lowest yet for Visit 3: previous totals were 19 in 2013 (10 Reeds), 32 in 2012 (18 Reeds) and 54 in 2011 (16 Reeds, but the high total includes 16 Sand Martins). This is perhaps a bit worrying given that it seemed to be a good early start to the season, so it'll be interesting to see how the rest of the season develops. One interesting captures was L494918 caught whilst puting up nets the night before; a bird ringed as a young juvenile at Marazion Marsh in 2001 and not caught since!

We fared better on Sunday, visiting 14 Barn Owl boxes between St Austell, Newquay and Penzance. Of these, most were occupied, which is an improvement on last year, and we captured six adults, four of which had already been ringed in previous seasons. Surprisingly two boxes still had incubating birds which seems very late, and two more had chicks too small to ring. But we did find several boxes with good sized chicks and ringed 18 birds in total.

Some of the smallest chicks, less than a week old

This amorphous blob confused us for a moment, but is a
remarkably fluffy 2-3 week old chick, along with
three unhatched eggs

A bit more like the size we like to find birds to ring,
although we did leave one smaller (doomed?) sibling in the box

A couple of Stock Dove interlopers in the same box
they were in last year, near St Mawgan

CES rosefinch and island Cormorants

The continued high pressure gave us a great chance to do some catching up before a few of us are off cannon-netting gulls on Guernsey next week. First on the agenda was CES yesterday, with ours at Gunwalloe catching 16 birds, mostly Reed and Sedge Warbler. This compares to 19 birds last year (15 Reed Warblers), 29 in 2011 (19 Reed Warblers) and 33 in 2011 (15 Reed Warblers).

We were, however, beaten by the Nanjizal CES near Land's End, which netted 87 birds including a couple of Grasshopper Warblers, a Spotted Flycatcher and this surprisingly rather smart young male Common Rosefinch!

Today we were then able to get over to Mullion Island to ring a few Cormorants from the 51 nests we counted earlier in the season. There were a surprisingly large number of young birds (perhaps as many as 70), many quite well-grown, but we were able to corall a good number and colour-ringed 18 birds as part of our monitoring on the island.

With the outboard still dead, it was a long row out

The Cormorant colony can be seen just left of centre above the mallow

Some of the newly colour-ringed Cormorants

The three island explorers counting gull nests, as seen from the mainland

Once we'd got the Cormorant ringing out of the way, we were able to have a quick look round the island to count the number of occupied Great Black-backed Gull nests. We are bound to have missed some, but the total of 62 nests (with 174 eggs) was still pretty impressive. This is almost as many as on Looe Island, which vies with Mullion Island to hold the title of the county's largest colony!

Thanks to Emma for the Mullion photos from the mainland and Kester for the gripping rosefinch pic.

First CES

The first week of May sees the start of CES (Consant Effort Site) season at Gunwalloe, using standardised mist-netting to monitor the abundance, productivity and survival of breeding birds. This is our fourth year of CES in the reedbed at Gunwalloe and in all that time we've never managed to fit in the first visit due to windy weather, so today was a bit of a novelty! But a good novelty though, as in amongst the 16 birds caught was this very fine male Whinchat; the first to be caught by the group.

More usual fare were the returning warblers, with five Sedge and four Reed caught, including birds first ringed in 2011 and 2012. Interestingly, Y010039 was ringed as an adult on 25th May 2011, so is now at least five years old. Strangely, after ringing in May 2011, it was recaught 20 days later but not again until today... Not quite sure how it managed to evade nets for all that time!

Y101039, originally ringed as an adult in May 2011

Another bird with an interesting history is Reed Bunting L961915, ringed as a juvenile in August 2011 and then recaught just once each year since; in July 2012, July 2013 and then today.

The down side is that the reedbed site hasn't dried out much since last autumn and is, to say the least, a bit muddy now, requiring chest waders to stay vaguely clean. But even that doesn't help much and the only way to really clean up at the end of the session is the little-known 'grass angel' technique...

The main reedbed net ride at Gunwalloe

Ringing at Nanjizal, Cornwall's other CES

After detailing some of the highs and lows of our CES at Gunwalloe, here Kester Wilson gives a flavour of ringing in Penwith, where he also runs a CES at Nanjizal.

"The early part of the year was quiet, with most of my time spent improving the habitat on site. Last year's clearance around the bird feeders continued to improve the catches of finches and Lesser Redpoll, Siskin, Brambling and last year's Cirl Bunting were all caught in the first few months of the year.

Every year has its quiet times and if you're lucky a few purple patches. During spring 2013, the purple patches were few in number, with winter dragging on well into spring. In late March, the wind turned southeast and many birders noticed large numbers of Chiffchaffs in the far southwest of Britain. On 25th March, my nets were opened and 118 Chiffchaffs caught, two of which were controls: DLL278 was ringed at Icklesham (East Sussex) on 18/9/2010 and EKX125 was ringed at Portishead (Somerset) on 1/7/2012. Soon after, details of three more controls were received and gave a further indicator that most of the birds involved were destined for southern Britain. EPL449 was ringed at Nanjizal on 30th March and found dead at Crew (Somerset) on 1/5/13, another ringed on 26th March was controlled a few weeks later at Slapton Ley (Devon), and another ringed during the same period  on Skokholm (Dyfed) stayed to breed at Nanjizal instead of heading back further north.

Compare this to the spring of 2011, when prolonged periods of southeasterly winds brought larger numbers of abietinus Chiffchaffs than usual and in amongst them were two interesting controls. One ringed at Sul Panaro, Italy, on 2/10/2009 and controlled on 4/5/2011 and another ringed at Giessen, Germany, on 26/9/2010 and controlled at Nanjizal on 7/4/2011.

Spring/summer 2013 didn't produce any further noticeable falls, just the odd surprise turning up in a net; the most surprising being a female Subalpine Warbler caught on 5th July.

After last year's poor breeding season, it was nice to be catching good numbers of young birds on CES and most species seem to have done OK, with both Sedge Warbler and Dunnock doing very well, and only Blackcap having a poor year. See below the numbers of young birds ringed of selected species during the whole CES season in 2012 and to the end of July only in 2013.

Year	2012	2013
Dunnock	39	34
Wren	37	62
Sedge Warbler	26	39
Whitethroat	3	11
Chiffchaff	115	98
Blackcap	15	6

For the first time I have used tapes at Nanjizal this autumn and my change of heart came with the chance of purchasing cheap, small MP3 players with decent rechargeable batteries.  Once the CES visits were completed I started to play Grasshopper Warbler just before sunrise and I am sure other people have noticed that Gropper tapes also work very well for Sedge Warbler: I later found that you can pretty much play any warbler and other species will respond. Up to 24th September, I have now ringed a surprising total of 53 Grashopper Warblers!

Further confirmation of a good breeding season for Sedge Warblers sees my annual total now over 500, a high percentage of which were trapped around the Gropper tape. An Aquatic Warbler also seemed to find it appealing on the 20th, only the second bird seen in the UK this autumn!

Until last week, numbers of Blackcap had been unusually low, but they have now arrived en masse and the 20th alone saw 98 being ringed, bringing my annual total over the 400 mark. As well as the large numbers of birds, the last few ringing sessions have produced the afore-mentioned Aquatic, Marsh Warbler (22nd) and a Wryneck (24th). A few recoveries have also come in over the last few weeks and the Skokholm-ringed Chiffchaff reappeared in a net a few days ago."