Trewavas Kittiwakes 2016

You might have seen a few posts from us over the summer with various photos of Kittiwakes at our study site at Trewavas/Rinsey, but yesterday saw effectively our last trip to the colony. With many failed breeders now departed and numerous chicks fledged, the colony has become rather quiet, or in the case of Rinsey deserted!

So what better time to offer a brief summary of the year. On the good side, the two sites at Trewavas Head fared pretty well, holding over 120 pairs of birds. This compares to around 70 in previous years so was a welcome increase. Some of these birds may have relocated from Rinsey though, where numbers were again very low (more on that later). Records of colour-ringed birds give us a little bit of insight into these movements and this year we saw six birds at Trewavas that had been recorded previously at Rinsey. Two of these were actually ringed as chicks in France (in 2007 and 2008), giving yet more insight into how these birds move around.

Part of the colony at Trewavas Head

Other French-ringed birds at Trewavas included birds ringed as chicks in 2002 and 2005. We also recorded 16 birds ringed at Trewavas in previous years, including a bird also photographed at sea in 2014 (see pics here), and also a bird originally ringed on the Isles of Scilly in 1996, caught and colour-ringed here in 2015.

At Rinsey, the only colour-ringed birds seen were a French bird ringed as a chick in 2005 and seen quite regularly and a lone bird ringed by us in 2013, which visited just once in February 2016. Breeding at Rinsey was also a write-off, with just nine pairs attempting to nest but all failing before the end of the season.

So a season of good and bad across the sites, but with some interesting stories building...

Full day of seabirds (and some cannibalism)

You know it's seabird time of year when you're heading out ringing for the day and your roof rack looks like this! Add to that a back seat full of paddles, buoyancy aids, drybag, VHF radio and an assortment of rings and colour rings and we were in for a long day...

First port of call was to take two boats over to Mullion Island to try to track down some of the 203 Great Black-backed Gull chicks/eggs we'd counted earlier in the year. Very few birds make it to a ringable size though, but with a record count this year hopes were high. The vegetation was, as ever, challenging and wading through the mallow and sea kale looking for chicks is a laborious job.

Even large chicks are remarkably good at hiding in low vegetation

True to form we found very few birds, which is always a bit depressing; a full sweep of the island found just 13 birds! These were all a good size to ring and colour ring, so it'll be interesting to see where these birds go wandering.

Some birds aren't quite so good at hide-and-seek though

Part of the reason so few birds survive to this stage was evident all around the island though, with at least 16 relatively freshly-dead chicks found. Some of these were pretty well-grown so it does look like predation (or more accurately cannibalism) remains a driver of the low productivity on the island. We're not sure how commonplace this is, but it doesn't seem to be the best strategy for a colonial-nesting bird!

Once we were back over from Mullion, we headed straight round to Praa Sands for the long paddle round to Trewavas Head to the second of our Kittiwake sites (only accessible by kayak). Unfortunately, the swell was way higher than forecast, so it wasn't safe to land and in any case the tide was really high which would have made accessing nest sites rather treacherous! This isn't the easiest of jobs at the best of times, as kayaking round the headlands with a double-ladder strapped to the side of your kayak is tiring to say the least. Makes landing interesting as well and I must admit we did get barrelled by a wave coming back in to Praa Sands.

Last job of the day (after an impromptu ringing group BBQ in the evening sun) was to make the most of a calm, new moon night to get nets up for Storm Petrels. The first net round before midnight produced over 25 birds so we knew we were in for a busy night, but sadly the Cornish mizzle came in at 1am and we had to beat a hasty retreat before the rocks got too slippy. But although we'd not made it to the busiest time of the night the total of 55 new birds was pretty good. It was a bit surprising to find these were all new birds, so we'll just have to go out again on Tuesday night and hope to recatch some ringed birds...

Better Kittiwake news but bad for Barn Owls

The last few days have been rather busy, so only a quick update for now! In essence, Barn Owls seem to be doing quite badly (deserted clutches, stunted growth and massively reduced broods) whilst the Kittiwakes at Trewavas Head seem to be doing OK. We've also managed a ringing demonstration at Gunwalloe and hosted a visiting ringer from Devon.

More details to follow once we've caught up after Great Black-backed Gulls, Kittiwakes and Storm Petrels tomorrow, but for now enjoy a few Kittiwake pics from Trewavas Head...

We counted at least 71 nests which is the most we've ever had here:
birds from the crashing Rinsey colony perhaps?

Most birds were a good size for ringing,
but some were too small even for a metal ring

AU is an interesting bird. Now breeding at Trewavas Head,
it was ringed as a breeding bird at Rinsey in 2012 and seen there
three times in 2013 but not seen in either 2014 or 2015.

Highs and lows in the Kittiwake world

Just for a change of scenery I headed up to look for some colour-ringed birds in the Kittiwake colony at Porthmissen, Trevone this afternoon. In many ways this was a day of highs and lows, quite nicely reflecting the life of a Kittiwake.

The first high was the site, as this part of the north Cornwall coast really is quite stunning! The birds are best viewed from across a narrow isthmus looking back into the colony, nesting along a series of narrow ledges across the sheer face.

The high was soon replaced with a low though, as on scanning through the colony it soon became apparent that a vast majority of the nests were empty, some with attendant adults, some abandoned. This has recently been one of the key sites in the county for Kittiwake and to see it so devoid of new life was quite depressing. The last few years have seen huge declines in Kittiwakes across the whole south of their range, so we're just hoping that the big declines in key sites in Cornwall are just temporary blips.

The next high came when scanning through the core of the colony, waiting for birds to stand or and shuffle to check them for rings. I was expecting to find one or two French-ringed bird, but found none. But far more interesting to me was a bird that leap out at me as having one of our rings from the Lizard (60km away)! Thankfully it wasn't too far away to read and it turns out that 'AL' has a far from mundane history. It was actually ringed as a chick on Gugh, on the Isles of Scilly, in 1999 and was recaught by us at Rinsey in June 2012, when we added one of our colour rings. It was then seen three more times at Rinsey in 2012, six times in 2013 and just once in 2014 which was the year the colony crashed there. So we don't really know when it first moved to Porthmissen, but it is certainly one to look out for there in future.

The world's worst digi-scoped photo, with the 17-year-old AL on the right

After that quite special high, I was then plunged into a rather depressing low with the arrival of a juvenile (female?) Peregrine. After a short while visiting empty parts of the colony, it then happened upon a ledge with four nests on it, all with attendant adults. The first brooding Kittiwake put up quite a fight, but with the adults soon displaced, the Peregrine proceeded to jump from nest to nest along the ledge, taking all four chicks from these nests (all were broods of one) over 45 minutes. The first three were eaten at the nest, with only feeble mobbing from the parents, though one adult did manage to knock the Peregrine off the ledge, which then carried the last chick off to the clifftop to eat.

Juvenile Peregrine predating the first of the four Kittiwakes nests in this photo,
with other attendant adults unable to intervene

Whether this is a new behaviour or a regular occurrence is unknown, but this may go part way to explain why there were so many empty nests in other parts of the colony. That's nature though, even if it is mightily depressing!

Breeding Stormies on the Brisons

The Brisons lie just off Cape Cornwall and really haven't been visited for a decade, so it was about time we made the effort and went and had a look! Thanks to the good fishing folk of Sennen Cove we were able to hitch a lift over for a couple of hours and ring a good number of birds and also try to get a handle on the number of breeding birds over there.

In total we were able to ring 42 Shags (two adults), 13 Razorbill (seven adults) and an unexpected 11 Guillemot (eight adults). Many auks were still on eggs, with a few abandoned Shag nests and several still with small chicks.

More significantly though, we also heard at least two Storm Petrels calling (or singing) from one of the boulder fields. This remains the only site in the county that Storm Petrel have been presumed to breed, although we're sure that other several other sites must exist but are just hard to access.

Very cute Razorbill chick, many of which are somewhat
difficult to get at in the boulder fields (below)!

Most Shag nests had broods of two, but a few had three feisty chicks

Adult Razorbill

Last of the Choughs

Not quite as ominous as it sounds, but this week saw us ringing the final brood of Chough chicks for the year. A small but very experienced rope team joined us to help us access this new site on National Trust land. A short abseil and some inventive ladder-work later and we found the nest, with three small but healthy chicks. This is rather notable as the female here is just one year old and breeding in their first year is exceptional in Choughs. Her partner is a three-year-old male so almost as inexperienced.

Choughs do always pick the most stunning locations to nest

...although this can make access 'interesting'!

The three chicks were big enough to ring but not big enough to know their sex, which is normally judged on size (by measuring leg length). All were good weights though, so hopefully will all fledge in the coming weeks.

This brings the number of Cornish chicks colour-ringed this year to 15; slightly down on previous years, but a great result considering several of these broods were raised by young, inexperienced birds. Many thanks to Alan, Roo, Christian and Will for their expert advice and help in safely accessing the site and to the RSPB staff and volunteers for monitoring the site in advance of our visit.

New moon Stormies

The first summer new moon coincided with a period of nice still weather so we had the chance to do some nocturnal netting for Storm Petrels. We headed to Hot Point, Lizard on the last two nights, netting a total of 52 birds. This is more than we've caught so early in the year before so worth the missed sleep!

Close up you can see where these 'tubenoses' get their name from

Most of these were new birds, but we did recatch birds we'd ringed there in June and July last year which is interesting and also a single French-ringed bird. Cornwall really does get the lion's share of French birds with 2/6 birds caught in the UK in 2015 being caught in Cornwall.

We sometimes catch birds with parts of feet or legs missing and the last couple of nights saw a bird missing a whole leg and one just missing the end of its foot. This doesn't seem to hinder them too much though which is lucky!

This is as drastic an amputation as we've seen!

Lizard Choughs

Being a bit behind the other pairs, yesterday saw us finally scrambling round to see how the Lizard Choughs were doing. We weren't quite sure what we'd find in the nest, so it was a pleasant surprise to find four chicks in the rather tight fissure in the cave.

As Cornish Choughs go this site was quite accessible!

Unfortunately one of the chicks was a bit of a runt, being 50g lighter than its siblings, so it'll be interesting to see if it survives. Apart from the runt, the other birds were all given a unique combination of colour rings which will allow us to follow their fortunes in the coming years. Measuring the leg length also gives us a good indication of sex and the three larger birds appeared to be two females and a male.

All four chicks safely returned to their rather scruffy nest

The Lizard brood brings the number of chicks ringed this year to 13, with one further site to check next week. This figure may seem low in comparison to previous years, but many of this year's pairs were inexperienced birds, so this number will only increase.

Many thanks as ever to all of the dedicated Chough-watchers who make our life so much easier by following these birds and working out hatching dates and to Cat Lee from the National Trust for the photos. More information on these iconic birds can be found on the Cornish Choughs website.

Geebs top 200 on Mullion Island

Bank holiday Monday seemed to be the perfect day for a spot of kayaking, so three of us headed out to Mullion Island to have our first count of Great Black-backed Gull nests.

Great Black-backed Gulls are spread across the island, here looking back to Mullion Cove

At first there didn't seem to be many birds on the island, but as we swept the island there were plenty of nests. Most were still with unhatched eggs, though some did have small chicks. In total we recorded some 83 nests containing 204 eggs/chicks, which is by far the highest number in recent years.

	2013	2014	2015	2016
GBB Gull nests	-	62	37	83
GBB Gull eggs/chicks	98	174	90	204
GBB Gull chicks ringed	4	17	12	-

The high nest count is great news and almost rivals the key Cornwall site at Looe Island, where 86 nests were counted last week. We've always seen very low survival rates to fledging though, so it'll be interesting to see how many of these 204 eggs and chicks survive the coming weeks.

Many nests were just hatching

Barn Owls on the move

We did our first long day of Barn Owl boxes yesterday, checking a swathe of sites from Falmouth across to Godrevy. Around half were occupied, but not all pairs were breeding. It could be that some of these non-breeding birds were just in poorer condition, as the females on eggs were weighing up to 425g whilst those not breeding were more like 310g.

This non-breeding pair were at a site not occupied since we started the project in 2011

Those that were breeding were either on full clutches of eggs on with eggs just hatching, so it was almost perfect timing for the checks.

This site near Fourlanes is our most productive,
with four chicks a one egg left to hatch being a small brood by its own standards!
The birds perhaps laid two more eggs, now abandoned at the back of the box.

Several of the adults were already ringed, which is where the interesting information comes from. Of the three, only one was found where it was ringed, breeding in the same box since we started our monitoring project in 2011. The other two were part of a more interesting story.

A male now breeding near Praze-an-Beeble had originally been ringed as a chick 4km away near Rosewarne just last year. The male of this Rosewarne pair was also ringed, but had actually been ringed as a breeding bird near Gwinear (only 1km distant) last year. We're not sure if he left it was pushed out, but the Gwinear female is sat on a full clutch so has obviously found a new male!

Just to add to the story, the breeding female at Gwinear in 2014 and 2015 had been ringed as a chick near Godrevy in 2012, and a female now breeding at Greenberry Downs had been ringed as a chick at Gwinear in 2014! Are you keeping up...

Some of the movements of birds now breeding in the middle of the project area

Super early Kittiwake chick

A quick trip out to Portreath this morning to check for Kittiwake eggs brought an unexpected surprise. Aside from three French-ringed birds and several birds on 1-2 eggs, an adult was seen brooding a single downy chick. This is 5-6 weeks earlier than in previous years and seems to be incredibly early compared to other studies.

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!

Cornwall ringing isn't for the faint-hearted!

The last couple of days seem to have been a bit full on, but full of adventure! Yesterday a small team joined the ringing legend that is Tony Cross to do the annual round of Chough sites in the county, colour-ringing chicks to continue the RSPB's long-term work on the recolonisation of Cornwall by these enigmatic birds. It's a dirty and very hard job, requiring an array of climbing kit, but a full-day saw us checking most of the sites, with mixed success. Whilst some nests were empty or predated, we did ring healthy broods of two, three and four, with a few more to check next week. This might not seem very many, but the breeding population is dominated by young, inexperienced birds at the moment, so things will improve in time...

Some sites are more accessible than others!
After a long abseil and then a secondary abseil down this ominous hole,
this nest was seemingly predated...

Somewhere near the bottom of this very large hole lies a very well-hidden nest site...

Ascending back to level ground after a 50m abseil down to the afore-mentioned nest,
where four chicks were ringed

Even by Chough standards this was a pretty tight squeeze!

Three chicks from an open mine shaft site getting their first view of the outside world!

The long day yesterday was followed by a more sedate one today. Accompanied by two surveying apprentices from Natural England we did the first of our checks on Barn Owl boxes. We only visited half a dozen sites, finding birds on eggs, including one clutch of five eggs.The afternoon was then spent kayaking out to one of our Kittiwake sites at Trewavas Head to read some colour-rings on returning birds. Whilst we only found four of our own birds and a single French-ringed bird, we take any opportunity for a kayak out on a sunny day!

Standard kit for West Cornwall Ringing Group being a wetsuit
and a dry-bag to put your scope in!

Bonjour mouette tridactyle!

...which literally translates as hello three-toed gull, but really just relates to a few French-ringed Kittiwakes at Portreath this afternoon. 'Tridactyle' also relates to the Kittiwake's scientific name (Rissa tridactyla), and there are many other tridactyl animals, including a sloth, a giant-anteater, a woodpecker, a Jacamar (related to kingfishers), an Australian marsupial, a plume moth, a polychaete worm, an extinct scorpion-like arthropod and, oddly, Plum Powdery Mildew!

But back to Kittiwakes... So a sunny afternoon just cries out for a trip to the cliffs to check out the satellite colony at Portreath, with the main colony only viewable from sea. But even this small gathering of birds was worth an extended look, and no fewer than four French-ringed birds were recorded. All of these birds will have come from Point du Raz in France, so it'll be interesting to see when they were ringed and if they have interesting histories...

Two of these appeared to be 'squatters' which aren't actively breeding but just prospecting. Birds will exhibit this kind of behaviour until a nesting 'stump' becomes available which they will occupy. Excuse the poor photo quality, but phone-scoping at 60x magnification in heat haze is never going to produce the best results!

The satellite colony at Portreath is up and left from the beach in this view

OWM-YGO looks to be a settled breeder

ONM-OLY was seen on several 'stumps' so is more likely a squatter

OBM-WBG was probably also a squatter