14 August 2018

Cornish Barn Owls in 2018

With all of our Barn Owl sites now visited for the year, it's a good time to crunch the numbers and see how they've fared this year. This is our eighth year of monitoring boxes in Cornwall, but we'll just compare 2018 to the last five years for ease:


20132014 2015 2016 2017 2018
Sites visited 32 44 41 47 64 85
Unoccupied 12
(38%)
11
(27%)
11
(27%)
12
(26%)
23
(36%)
34
(40%)
Occupied but no breeding 7
(22%)
7
(18%)
7
(12%)
8
(17%)
5
(8%)
4
(5%)
Average clutch size
(where observed)
3.64.6 4.64.65.3 5.2
Average brood size
(where observed)
2.43.5 3.52.83.0 3.3
Number of chicks ringed 1963 704790 126

The larger number of boxes visited is due to the funding from Paradise Park which has allowed us to really expand the scope of the project. There are several more new sites for 2018 as well which we hope will be occupied in the coming years. The high rate of unoccupied boxes is also due to the large number of new sites that birds have yet to move into.

However, we did see several regular sites unoccupied for the first time which may well be due to the mortality over the hard late winter weather. These two periods of snow cover won't have made it easy for birds to get in condition for breeding and it does seem that some regular sites weren't occupied, but those that did breed made the most of the good spring weather by laying quite big clutches (including a clutch of seven at one site). But we then saw one of the hottest and driest periods on record, which seriously stunted grass growth, and no grass means no voles. So most sites then saw significant brood reductions, though the average of 3.3 chicks still compared well to previous years.

We also think the 'Beast from the East' has had a greater impact on the breeding population than you might think, apparent by the number of birds breeding in their first year. This summer we've caught 15 adults already carrying rings, of which six were ringed as chicks in 2017. Compare this to the totals from the previous few years:

Year Ringed adults
caught
Ringed as chick
previous year
2018  15 6
2017 11 0
2016 9 2
2015 8 2
2014 13 0

We can only assume that these birds (some at regular sites) were new recruits following the death of an 'original' adult, but if this has happened across the whole population then that my lead to quite a drop in the average breeding age. But that's why we do what we do and what the project is all about; understanding these changes in the county's Barn Owls.

16 July 2018

Cracking Stormie night and more French Kittiwakes

Same old, same old it seems at this time of year, but when the 'same old' is ringing Barn Owls, Kittiwakes and Storm Petrels then it's not so bad! With over half of our second visits to owl boxes now completed, it looks like the good start to the year hasn't quite come to fruition. Out of the clutches of five or six eggs we were seeing, we seem to be down to broods of just two or three chicks now, which perhaps isn't surprising considering the weather. It might be glorious out there, but the lack of rain means a lack of grass growth and a lack of rodents, so not good for demanding owlets! It's not all been bad news though and we have still seen a few broods of four or five chicks.


Sometimes the adults are just all very relaxed at nest visits,
watching from a handy perch!

Aside from owls, we had our first big Storm Petrel catch of the year at Gwennap Head, Porthgwarra at the weekend. A long busy night saw us ringing 159 birds, also catching six BTO-ringed birds from sites as diverse as Calf of Man, Cape Clear and Hartland Point, Devon. We also caught one French-ringed bird which I have a feeling is an old one, so it'll be interesting to see when that was ringed.

Last but not least, we caught up on some Kittiwake ringing and resighting recently and managed to ring 24 chicks at Trewavas Head. It's a real pity here that most nests are out of reach of a double ladder, but I guess they need to be safe from the Cornish swell! A quick look at Cornish resightings so far in 2018 shows that we've now seen 26 different French-ringed birds this year; eight at Trewavas Head, eight 'loafers' at Lizard, six at Ralph's Cupboard, Portreath and three at Rinsey. This is even more impressive when you consider that to the end of 2016 there had only been 92 reports of French-ringed Kittiwakes in the UK outside of Cornwall! We're sure there are many more out there, so we'll be out again in the week to check...

30 June 2018

Seabird Saturday

Our annual gull-ringing trip over to Mullion Island is never the most productive affair, with the Great Black-backs there having very low productivity indeed. But kayaking over this morning we were met with a bit of an eerie silence, with very few alarming adults overhead. It looked like the hot weather had wilted off most of the vegetation on the island, most of which was laying flat, making it hard to check for chicks. But despite our best efforts we could only find a single gull chick on the whole island! We estimated over 60 nests for the island earlier in the year, so if they've only produced one chick then something is very wrong...



Perhaps linked to the poor breeding season of gulls on Mullion Island, there has also been a large gathering of non-breeding Kittiwakes off Lizard Head. We've seen at least on of our Rinsey/Trewavas birds there (but too distant to read the ring), but this morning three French-ringed birds were present, photographed by Terry Thirlaway.



Two of these were birds ringed as chicks in Brittany in 2016 and 2017 (hence definitely not of breeding age yet), but the other refused to show off it's full ring combination so remains a mystery for now.

24 June 2018

Our first ever KITTI chick returns!

Oh we love a high pressure! The weather has been just perfect the last few days to catch up on a few seabird chores, so a small group of us ventured out to our Kittiwake sites at Trewavas Head on Friday. While two of us paddled round from Porthleven, two scrambled round to meet us at the bottom of the cliffs for a lift around the last section only normally accessible on a low spring tide.


Having already caught many of the 'low-hanging fruit' in the colonies, it's becoming harder to target new birds, but perhaps that's a good sign that our catching has been going well. So between the two sites we only ringed a further nine adults, but did also manage to read a good number of rings on adults ringed in previous years. We also resighted a new French-ringed bird to us, originally ringed as a chick at Pointe du Raz, Brittany, in 2013.

But the highlight was spotted as we paddled back along the coast. A small face we've had our eye on had three Kittiwake nests on it with a few adults hanging round, one of which looked to be ringed. So with some dubious kayak-landing and a bit of a sketchy climb in shorts and wetsuit boots, we managed to confirm that this was PP (below); the first ever resighting of a bird we'd previously ringed as a chick (in 2015).

21 May 2018

Meet Antonio and José

The group had a busy weekend, out and about on both days. On Saturday we were once again helped out by Alan and Roo (from Rope Geeks) to safely access the first Chough nests of the season to continue the colour-ringing project. We managed to access two nests in mine shafts in West Penwith and a sea cave nest site on the Lizard, ringing a total of 10 chicks. This is a great result for all of these sites and we hope to be visiting a few more in the coming week.

There were of course a couple of other big events happening on Saturday (Royal wedding and FA Cup final for those reading this way in the future), so in recognition of this, meet Antonio and José who we ringed at one of the sites.


Brood of four chicks happily back in their sea-cave nest after ringing

Sunday was a bit less strenuous, but rather busier, as we were running a ringing demonstration and nest-finding trips at the Cornwall Wildlife Trust event at Caerhays Castle. In the nets we caught a nice variety of birds, including Great Spotted Woodpecker and Jay, and also managed to show families various nests including Robin, Dunnock, Song Thrush, Blue Tit, Great Tit and Coal Tit.

Newly-hatched Song Thrush chicks
Endoscope view of a brooding Great Tit

16 May 2018

First owls of the year

With the prospect of a late breeding season following the spring snow, we had a tour round a few Barn Owl sites yesterday to see how birds were getting on. Covering a patch from Hayle up to Newquay we visited 14 sites, with rather mixed results.


A couple of the sites are quite new to the project, so it wasn't surprising they weren't occupied, but three sites we'd expect to be occupied were empty. There were also two sites with birds present but not breeding, so this does seem quite a high number.

This did leave several sites with birds in residence, but even some of these sites had new, unringed birds present. In fact we ringed nine birds at six sites, with just one recapture and even this was a bird ringed as a chick nearby the previous year. So although many of these birds had clutches of five or six eggs it may be that many new birds have been recruited, so it'll be interesting to see how the season progresses.

29 April 2018

The best fieldwork site!

It was such a stunning spring day yesterday that there was only one place to be... out on the water! So we fitted in another visit to the Kittiwakes at Trewavas Head, this time managing to land by the engine houses. This part of the colony was worryingly quiet though, with fewer than 50 birds on the ledges, instead of the usual 65+ pairs! Just three of our colour-ringed birds were present, but hopefully this is just a slow start to the season here.


The main face at Trewavas Head was slightly busier which was encouraging. Here we were able to record a further dozen of our own birds, including two that have previously been seen on their wanderings - see here and here.

It was also great to see two of our birds as a pair now,
giving us much better information on the workings of the colony

In amongst our own colour-birds were three French-ringed birds. Two of these are known to us already, but typically the one new bird to us was so high up on the face we could only see two colours and part of the metal ring, so it remains unknown (for now!).

ONN-YOM was ringed as a chick at Pointe du Raz in 2002
and has been regular at Trewavas since we first visited in 2012
OWM-RNN was ringed as a chick at Pointe du Raz in 2007
and has been seen six out of the last seven years at Trewavas

14 April 2018

Any excuse for a paddle

This morning a couple of us took to the opportunity for a paddle out to check out the Kittiwakes at Trewavas Head. Leaving from Porthleven, the swellier-than-predicted swell made things a little slow going and we were also unable to safely put the kayak in at the engine houses, so had to make do with a visit to just the main headland colony.

With only around 60 birds there at any time, numbers were down on previous years, but the to-ing and fro-ing of birds mean that we were able to record 19 colour-ringed birds as part of our RAS (Retrapping Adults for Survival) project. The 19 included 17 of our own birds and two French birds that are now regular breeders here. One of 'our' birds was originally ringed as a chick on Gugh, Isles of Scilly, in 1996, having a colour ring added by us in 2015. So at 22 years old this is our oldest bird in the project.


The pic above shows two of the other more interesting birds. AP is a bird we ringed as an adult at Rinsey Cliffs in 2012, remaining there until 2014 when the colony there effectively collapsed. It was one of the few birds that relocated to Trewavas Head, seen just once in 2016 and 2017. The rather more colourful bird was ringed as a chick in 2007 at Pointe du Raz, Brittany, France. It was seen in France in 2009 and 2010, then at Rinsey in 2012 and 2013, before moving to Trewavas Head from 2015 onwards.

Of the other birds, two had also been seen on their coastal wanderings, with one photographed at sea off Longstones Lighthouse in July 2014 and another seen at Gwennap Head in August 2017.

7 April 2018

Russian-ringed Siskin visits Penryn!

It's been a while since we've blogged, but with incessant poor weather and a late breeding/migration season we've really not been up to much! But some regular ringing did pay off recently, as Robbie Phillips relates:

"After ringing on the University of Exeter’s Cornwall campus for the last four years it’s always nice to have a new species for the site, so to catch three iskin midweek was a highlight. We were out again last weekend when a ringed Siskin was found in the net and I just expected it to be one from earlier in the week, so it was a shock to find that it wasn’t. Even more surprising was that it was carrying a foreign ring, and from Russia!! Where abouts in Russia the bird, aged as an adult female, had come from we thought would take some time to find out. For my first foreign control, I couldn’t have asked for more, well worth the years of visits and hundreds of Blue Tits."


Incredibly, just 10 days after catching this bird, we heard news from the Russian Ringing Scheme. 'Our' Siskin had been ringed as second-year female in April 2017 at Rybachiy in the eastern Baltic, over 1800km from Penryn. It had presumably been ringed on spring migration, so may well have bred even  further east than Rybachiy! There have been fewer than 20 Russian-ringed Siskin found in the UK, but this is also the first ever foreign-ringed Siskin to be found in Cornwall.

22 February 2018

Spring is in the air

It hasn't really felt like spring the last couple of mornings, with frosty cars and freezing cold metal poles! But once the sun was up, Dunnocks and Chiffchaffs were singing and Goldcrests displaying to each other at the sewage works, so things are definitely getting going.

But there's still plenty of signs of winter around, with this rather subtle Siberian Chiffchaff one of the last birds ringed this morning at Carnon Downs STW. It showed quite a lot of green tones to the upperparts and tail, but was nice and plain underneath and also had the distinctive long supercilium we see of some Sibe Chiffs. There was also a remaining Yellow-browed Warbler, but even this was darting round wing-fluttering at a Goldcrest!



In fact the last bird of the morning could be a sign of winter of a sign of spring, as this male Blackcap could wel be a wintering bird, but the fact it had a good amount of pollen on its forehead might indicate it was travelled from points south recently. We did look around for any pollinating trees nearby but even the local catkins weren't producing much pollen yet.

But the fact that we only caught three Chiffchaffs at Carnon Downs STW this morning and just one at Gwennap STW yesterday is perhaps a sign that birds have already started to move north, or at least have other things on their mind...

15 January 2018

Wandering Peregrine

It's not often we get the chance to read colour-rings on Peregrines outside of the breeding season, as birds are often hard to pin down to a single location to read the ring. But with a few local photographers becoming more aware of the various colour-ringing projects we run, the chances of reading rings on fly-by birds is increasing.

But it was a member of the ringing group who photographed a passing Peregrine near Predannack Airfield yesterday, only to find it was wearing a yellow colour-ring.


The group has been using yellow colour rings on Peregrines for several years now, so we presumed it was a local bird, but it was a surprise to find it was actually ringed as a chick in north Cornwall in 2016. We've had a few long-distance movements before of our own birds, but it's always nice to have a surprise like this. Thanks to Tony Blunden for the photo and Tony John for confirming the details for the bird.

7 January 2018

Returning Sibe Chiff kicks off 2018

In the first mist-netting venture of the year, it only seemed right to head to the sewage works. So just two of us braved the early morning frost to get a few nets up at Gwennap Sewage Works. It took a while for the sun to stir up the insects enough to get birds moving, but once they did (and with the addition of a 'sewage mix' on the MP3) we didn't do too bad, ending up with 62 birds.

The total included 23 Chiffchaffs, two of which were Siberian 'tristis' Chiffchaffs. Interestingly, one of these was already carrying a ring, having been ringed at Gwennap in December 2016. This is only the second time we've recaught a tristis in a subsequent winter, adding to the evidence that these are returning wintering birds, not lost vagrants.

Of just as much interest was the recapture of the bird below, originally ringed in September 2016 in North Norfolk! This was presumably a recent autumn arrival in Norfolk when ringed, so was presumably from points north/east.


Just to round off the day nicely, and very typical of this autumn/winter, we ringed an impressive NINE Firecrest, which is a good winter total, never mind from one morning.

29 December 2017

First Chiffchaffs of the winter

Mist-netting has been a bit slow of late, but with the weather finally turning cold and the wind amazingly light we took the opportunity to make our first visit to the local sewage works. First stop was Gwennap, where as many as 65 Chiffchaffs were feeding in low hedges and bushes around the site, so with just two nets we were able to catch 35 birds, including a single 'tristis' bird and also two birds ringed last winter (both on 5th January). We only caught five adults, so two ringed was a reasonable ratio!

Next stop was Carnon Downs, where there were fewer Chiffchaffs (perhaps just 25), but they were all now in the tops of the trees in the warmer afternoon, so we only caught a single bird. But we did see another 'tristis' bird and also a ringed bird, so we'll be back again as soon as the wind and weather are favourable.

Apologies for the lack of photos, but we were a bit busy ringing birds to take photos...

14 November 2017

Lost Greenland White-front reunited with family

White-fronted Goose isn't the commonest bird in Cornwall, so Alan James was happy enough to find and photograph one on 1st November at Marazion Marsh. This was no ordinary bird though as it was carrying an orange neck collar and also a data logger.


Having spotted this we quickly emailed Tony Fox who was almost certainly responsible in some way for this bird. Thanks to Tony for the very quick response, which is summarised here.

Orange V3Y was a Greenland White-fronted Goose ringed at a place called Hvanneyri in west Iceland on 23rd September 2017 and was fitted with a GPS logging device and solar cell. Whilst at Hvanneyri it associated with CDZ (a juvenile male), another adult female fitted with a GPS logger and an unringed adult (probably male) that evaded capture. This small social group moved to a farm called Leirulækjarsel in Mýrar on 25th September where they remained until they departed.

The team don't have online access to live tracking data from V3Y, but the other GPS-tagged bird left Leirulækjarsel at around midday on 28th October en route to its wintering grounds in southern Ireland. What happened next is pretty amazing, because it made southern Ireland safely on its way south no problems, passing over Co Waterford at 4:30am on 29th October but seemed to not realise it was so close to Wexford! It continued southwards for some reason, eventually doing a tour of the Channel Islands and Brest in Brittany before turning back north, reaching Tacumshin in Co Wexford at 5:30am on 30th October. It rested only briefly before continuing north to Wexford Slobs, arriving at 7:20am the same day.

The GPS track of one (or all?) of the social group, all in under two days!
Without its own tracking data, the best guess is that V3Y followed a similar route for the majority of the journey, but got separated from the flock before turning up at Marazion Marsh on 1st November. But the story does have a happy ending, as John Wilson (who started the tracking project of Greenland White-fronted Geese back in 1983, resighted the whole social group (CDZ, V3Y, the GPS-logged bird and the unringed adult) at Wexford North Slob on 8th November. So despite an impromptu stop-off in Cornwall, V3Y found her way home eventually and rejoined her family!

**UPDATE** Thanks to Reuben Veal for adding to the story, as the bird he reported from St Gothian Sands on 5th November was V3Y, adding extra detail to this fascinating story!

Many thanks to Alan for allowing us to use his photo and to Tony for the rapid reply and very comprehensive history of this social group.

9 October 2017

Mixed fortunes for Cornish Barn Owls in 2017

Just before we get carried away with ringing autumn migrants, it's a good time to have a look back at the 2017 Barn Owl season. With extra project funding coming in and new boxes located and/or erected it's been a busy summer!


2011 2012 2013 2014 2015 2016 2017
Sites visited 32 34 32 44 41 47 64
Unoccupied 2
(6%)
7
(21%)
12
(38%)
11
(27%)
11
(27%)
12
(26%)
23
(36%)
Occupied but no breeding 13
(41%)
2
(6%)
7
(22%)
7
(18%)
7
(12%)
8
(17%)
5
(8%)
Average clutch size
(where observed)
4.8 4.1 3.6 4.6 4.6 4.6 5.3
Average brood size
(where observed)
3.1 3.1 2.4 3.5 3.5 2.8 3.0
Number of chicks ringed 33 46 19 63 70 47 90

With so many new boxes put up in recent years (thanks to generous funding from Paradise Park), it's perhaps not surprising that the apparent occupancy rate was slightly down in 2017, but this will no doubt improve over time as birds move into some of the newer boxes. The relatively dry spring would have been quite good for rodent numbers, but it was still surprising to find so many large clutches, with an average of 5.3 being the highest we've seen since we started monitoring in 2011.

However, as the weather deteriorated into the summer, we weren't expecting quite such large clutches and this proved to be true, Most sites saw quite significant brood reduction, though the average brood size of 3.1 was still pretty good given the conditions. After the four complete failures in 2016, we only saw two this year which is more normal. We also some failures just after fledging, with two chicks from one brood found dead in surrounding fields soon after fledging, and two chicks from another found dead in a water trough a month after fledging.

But the total of 90 chicks ringed was also our highest to date and hopefully we'll break the 100 barrier next year. As far as adults go, we retrapped several adults, including one male that has now been in the same box since 2011. We also retrapped an adult originally ringed at a site in 2015 (where it raised three chicks), then found in a box just over a kilometre away in 2016 (didn't breed), but then back in it's original site for 2017, but still not breeding. It'll be interesting to see if it breeds next year, and if so where.