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.

22 September 2017

Scottish Osprey drops into Devoran


Late summer and early autumn sees small numbers of Osprey staging in Cornwall on their southbound journey to west Africa. The wooded creeks and rivers that feed into Carrick Roads seem to be particularly favourable. Devoran Creek has had two individuals for the last few weeks and one of these juvenile birds was sporting a coded blue ring on the left leg. This instantly identified it as a Scottish bird as birds originating in England and Wales receive a colour ring on the right leg. Despite being quite showy the bird typically remained just out of range to read the ring, but with persistent observation and some digiscoping the ring was finally read as JF1.


This bird was ringed as a chick on 13th July this year near Monymusk, Aberdeenshire, by Grampian Ringing Group; one of a brood of three. On size, it was deemed likely to be a male and this is the first confirmed sighting of JF1 since leaving the nest.

JF1 in the nest just after ringing

With various Ospreys being seen elsewhere in the county it is very much worth looking out for these impressive birds and, if you’ve got your eye in, reading a colour ring! Thanks to Greg Wills for the words and pictures and Ewan Weston for the photo of JF1 in the nest.

9 September 2017

Curlew mystery solved

Thanks to Greg Wills for penning this post about his persistence in tracking down a mystery colour-ringed Curlew:

High tide roosts provide a perfect opportunity to pick through wader flocks for more unusual species and colour-ringed individuals. Gorrangorras Creek, adjoining Penryn River, plays host to one such roost, where birds gather on one of the few shingle banks waiting for the tide to retreat. The gathering typically holds good numbers of curlews and on 18th August a quick scan revealed a bird sporting a yellow colour ring. Due to worsening light, the complete code couldn't be determined and so a nervous wait took place hoping the bird would be present the next day in order to reveal the story the rings had to tell.


The following day after a brief walk further along the river, the flock was once again present; this time with distance and light on our side. The single ring instead revealed itself as a four-ring combination, all on the tibia.


Now the puzzle really began! The two lower rings were obviously metal and yellow, though the upper rings seemed off-white, something that needs to be checked with some scrutiny with light blue and light green (lime) rings all used regularly in schemes. And so ensued much deliberation between the observers, forum conversations and Curlew ringers across Europe. After much to-ing and fro-ing, the identity was confirmed as being an adult female ringed light blue/yellow, light blue/metal, ringed on its breeding grounds near Ladbergen, Steinfurt, Germany on 18th May 2012. She has returned to the same breeding area every year until 2017.


This isn't the first German-ringed Curlew to be found in Cornwall, with a bird from the same scheme Red/Metal, Red/Green seen at Rosemullion in August 2014. There was also a 25-year-old German-ringed bird killed by a bird of prey at Gwithian, a 20-year-old bird found dead near St Mawes and an 18-year-old bird hit by a car near Carnon Downs.

Thank you to Gerrit Gerritsen and Christian Kipp for their assistance in confirming the identity. Christian’s father Manfred has ringed round about 3,000 Curlews in Germany and between them they have resighted 160 colour-ringed birds in their breeding areas, most of them in Steinfurt.

3 September 2017

August at Nanjizal

Whilst September is the official start of autumn, migration has been in full swing at Nanjizal during August. During the month, there was no coverage from the 14th-20th (peak Sedge Warbler passage) due to family holidays and a short period at the start of the month. None the less, a non-too-shabby total of 1,698 new birds was achieved. Unlike a lot of coastal sites, good numbers of birds at Nanjizal usually coincide with still clear nights where the birds can pick good habitat, rather than being happy to land on the first bit of land they see whilst flying through inclement weather. As you can see from the totals the main species trapped are species that have a tendency to migrate SSW in autumn, with Sedge Warbler and Blackcap both funnelling down in big numbers. This funnel affect also brings a good number of dispersing British Robin, as we always get good numbers at the end of August into September. Other species such as Willow Warbler are never in such large numbers.

Top 10 species ringed in August
Sedge Warbler 837 Reed Warbler 80
Whitethroat 192 Grasshopper Warbler 56
Willow Warbler 176 Robin 56
Blackcap 107 Wren 25
Chiffchaff 102 Garden Warbler 14

Ringed birds recaught during the month came from Scotland, Leicestershire, Wales, Cheshire and Belgium, all bar one being Sedge Warblers. Most species seem to have done OK, with Whitethroat, Blue Tit, Great Tit and Grasshopper Warblers picking up after a slow start. Song Thrush seem to have done very well locally. Other unusual species ringed included seven Tree Pipit, two Firecrest and two Spotted Flycatcher.

The month also saw a few rare and scarce birds appear in the nets, predominantly birds from the south, as there hasn't been much arriving on the east coast to filter down. A blast of south-eastlies on the 22nd seemed to do the trick and a good run started with a Wryneck on the 24th, white-spotted Bluethroat on the 25th (one of 224 birds ringed that day). The 26th then produced the second Melodious Warbler of the month (the first was on the early date of 10th) and for the second month in a row a Blyth's Reed Warbler, this time a first-year bird.




30 August 2017

Something odd afoot in the Kittiwake world?

I'm not one for coincidences, but in all our years of colour-ringing Kittiwakes we've only ever had one sighting away from a breeding colony (a bird photographed at sea - more here) and no dead birds found. So it was a bit unusual that in one month we have reports of two dead birds and also two resightings. The first was one of this year's Trewavas Head chicks, found dead just a month later (on 12th August) at the unlikely location of Zeeland in The Netherlands. A second bird was then found dead in mid-August on Cape Clear Island off Co Cork, Ireland. UJ had also been ringed as a chick at Trewavas Head, in 2016.

The two sightings were both of birds at Porthgwarra (near Land's End), photographed by Jon Greep on 29th August. CP was ringed as an adult in 2013 and has been seen at Trewavas Head several times since, but always early in the season, never seen to be breeding. E2 was also ringed as an adult, in 2015, but hasn't been seen since. So we do wonder if these were both young, non-breeding birds when ringed.



So whether this run of unusual Kittiwake records is related to the same weather systems that have brought large numbers of seabirds over into the eastern Atlantic is unknown, but it does seem a very odd coincidence.

19 July 2017

Short summer summary

It's been a while since we blogged, but it doesn't mean we've not been busy. We're now at a stage where there are only two Barn Owl broods left to be ringed (with the running total now over 95 birds ringed this season), so will be looking at the numbers soon. It feels like the season started well, with plenty of large clutches, but has since gone downhill, with much smaller broods and a few failed sites. One site even had four large chicks where two attempted to fledge early and sadly ended up predated.

The limit of the first flight of one of the birds fledged from the barn in the background
Away from Barn Owls, our other main summer ringing once again focused on seabirds, with mixed fortunes. Our annual gull-ringing trip to Mullion Island was a quick affair, with the island seemingly devoid of gulls. In fact, we only found and ringed five chicks, which is the lowest number since 2013.

Slightly more successful were our Kittiwake trips to Trewavas Head, where we have continued to read colour rings on many of our own birds (43 from previous years) and also several French birds, some of which are now breeding here. We've also strayed further north to check the colonies Portreath and Porthmissen, the later being so much quieter than in previous years. From the precarious viewpoint at Porthmissen Bridge it's possible to see most of the ledges, but the photos below show large areas of the colony have failed completely, with around 60 nests still with chicks.



The occupied area of the colony...
...and the depressingly quiet deserted ledges
One of the two French-ringed birds at Porthmissen this week, ringed as a chick in 2003

If reading colour rings takes patience then reading metal rings is a whole different ball game! But two rings read in the last week were both worth the effort, even more so as they were both on upside down! A Cormorant at Helston Boating Lake was ringed as a chick on Little Saltee Island, Co Wexford, in 2016, and a Black-headed Gull at Swanpool, Falmouth (below) was ringed as an adult in Dorset in 2011.



29 June 2017

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.




24 June 2017

Busy week of Barn Owls, Kittiwakes and Stormies

We've spent lot of the last week catching up on monitoring and ringing of some of our breeding birds. This has mostly involved Barn Owl boxes and Kittiwakes, but also some new-moon Storm Petrel and urban gull ringing.

So far this year we've ringed 16 adult and 30 nestling Barn Owls, and recaught 10 adults already with rings (including this bird from Suffolk). The birds at Windmill Farm reserve on the Lizard always offer a surprise and this year was no exception. Last year we saw one of the palest chicks we'd ever seen in the brood there and again this year we ringed one very pale chick. But of more interest was the unusual patterning on the wing, with the outer three primaries very different to the rest!


Amongst the other boxes visited was this brood of four chicks which chose not to use the whole of the box, but simply all bundle up on top of each other!


Aside from monitoring the Kittiwakes at Portreath from the cliff-tops, we continued our colour-ringing project at Trewavas Head at the weekend. While two group members kayaked round from Portleven, one climbed in bringing along a ladder to help reach some of the more lofty ledges. It's a good sign when a lot of the birds in the colonies here are already ringed, so we only managed to add another nine adults to our colour-marked population.

OWM-RNN (hatched in France in 2007) with a chick at Trewavas Head, the first time we've seen it breeding. It's been seen at Trewavas Head every year since 2012 but this is its first breeding attempt.

As for Storm Petrels, despite the light wind and early date, we managed to catch an impressive 81 birds at Lizard on one night, including three birds that were already ringed. One of these was from the Channel Islands, with the others both being ringed in 2016 in west Wales. One was ringed on Skokholm Island on 26th July and the other at nearby St David's four days later, providing further proof of the Celtic links of our Stormies.

19 June 2017

Suffolk tourists visit the county

It's that time of year in sunny Cornwall where the roads slow down and lots of new faces arrive in the county on their summer holidays. Apparently this isn't just restricted to people though (emmits as we call them down here), with some birds from 'up-country' also finding Cornwall to their liking.

This might not be too surprising when we're talking migrants, but even we're surprised sometimes by the arrivals we find. Whilst recently checking Barn Owl boxes in the far west of Cornwall, we came across a ringed female in a box with her chicks, but the ring number was unfamiliar. It turns out this bird had been ringed as a chick the previous year in east Suffolk, which is quite remarkable! The box is monitored by the Suffolk Community Barn Owl Project and this looks to be by far the furthest movement they've heard of from their hundreds of boxes.

Many thanks to the National Trust West Cornwall Barn Owl Project for helping monitor these boxes in Penwith and to the Suffolk project for providing us with some quick feedback.

Most of our Barn Owls seem to be at this stage, with chicks mostly under two weeks old
As if this was surprising enough, I was emailed by Sue Sayer (Cornwall Seal Group) the very next day with details of a colour-ringed Kittiwake photographed during one of their boat-based surveys at Porthmissen earlier in the year. In a strange coincidence, this bird was also from Suffolk, ringed as a chick in Lowestoft in 2014. It was seen again in Lowestoft in June 2016 but not since and may well be a young bird prospecting new nest sites.


The movements of these two birds are not quite unprecedented, although the only Barn Owls to have travelled further to Cornwall were ringed in Germany and The Netherlands. The only Kittiwakes to have travelled further were from Northumberland (x2), Northern Ireland (x2) and Norway.

Origins of our two visitors: K (Kittiwake) and B (Barn Owl)

1 June 2017

Attacking the Mullion Mallow

With Mullion Island's Cormorants mostly all grown up, it was safe to head over to the island yesterday in two kayaks to do our first Great Black-backed Gull nest count of the year. A small team of four were able to cover most of the island, just missing out areas where the young Cormorants (and some Shags) were perched up on the cliff ledges.

Shag nests on the south side of the island
 

Whilst some birds were nesting on open ground, most were tucked deep in the Mallow that covers half of the island. This doesn't make nest counting very easy, hence needing a small team to be able to line-search through the vegetation, which is often over head height!






In total we located 70 nests, although we did miss some areas of the island. This compares reasonably well to the record count last year, but there were slightly fewer eggs/chicks than expected. Totals over the years for the island are shown below for info.


2013 2014 2015 2016 2017
GBB Gull nests
62 37 83 70
GBB Gull eggs/chicks 98 174 90 204 166
GBB Gull chicks ringed 4 17 12 13
Cormorant nests 24 52 50 39 47
Cormorant chicks ringed 11 19 7 16 0

Whilst on the island we were also hoping to ring some Shag chicks, but in the end only two right on top of the island were in a safe enough place to get to.