Another sewage Sibe, and a shiny new reedbed

Another frosty morning meant another look round some sewage works; this time our more regular ones. With very few birds at Carnon Downs we headed straight to Ponsanooth, where there were at least three Siberian Chiffchaff and a mix of other things. We only caught 30 birds, but that did include two very smart Grey Wagtails (dodgy Instagram photo below), a Woodpigeon and a few Chiffs.

One of the Chiffs was a classic Siberian tristis bird and we had the chance to grab a pic along with a more local bird for comparison.

Another interesting bird was a retrap Goldcrest from last winter, so one we know was an adult. Goldcrests are aged on tail shape, with juveniles more pointed than adults, but this bird wasn't the most obvious!

As the catch dried up, we had an hour spare to drop in to Gwennap, where the very amenable guys at South West Water appear to have created us a shiny new reedbed! This is a pretty exciting prospect and it'll be interesting to see how it develops and what birds it attracts.

Even in its current state it had already drawn in two Green Sandpiper, a Snipe and a Water Rail.

Arctic Tern logger update

A while ago we reported the finding of a mystery bird with a GPS data logger (more here), and we have just solved the mystery!

The mystery data logger

The Polish manufacturers of the device were able to download the data and identify the bird as an Estonian-ringed Arctic Tern, exactly as predicted! It was originally ringed on 26th June 2013 on Sorgu island (in red below), on the same day as the bird caught on the Ythan estuary that we mentioned in the original post.

Ringing locations of the Arctic Tern (red) and the three Common Terns (green).
View Cornish terns in a larger map.

This is the first Arctic Tern recovery in Cornwall, and we don't have many of the other tern species either! There are just seven records of British-ringed Sandwich Terns in the county and records of Common Terns ringed in Strathclyde, The Netherlands and Finland (in red above).

Halimodendri, blythi and margelenica - and rare warblers galore

Below Kester writes a quick summary of a reasonable autumn in Penwith:
 
As the mornings get ever more chilly and bird numbers start to dry up, thoughts of packing up the nets at Nanjizal for the winter pop into my head. The late autumn movements of thrushes and finches didn't seem to happen this year, with very low numbers flying over in the first few hours of light. Using a Redwing recording has boosted catches in the last few weeks, but Blackbirds that are usually so numerous in November are altogether missing. Chiffchaff catches remain low, as have Goldcrest and Firecrest, but one warbler caught in higher numbers than usual, mirroring the massive UK arrival, was Yellow-browed Warbler. Up until today, 15 birds have been caught, including an impressive five on 10th November alone! Other birds of note recently were a Dusky Warbler caught on 7th November and a very good candidate for a halimodendri Lesser Whitethroat on 13th November.

Dusky Warbler

Halimodendri Lesser Whitethroat

Tailt moult such as this in first-year halimodendri is actually rather common.

Interestingly, the DNA from this Lesser Whitethroat trapped in early October at Nanijzal came back as being of the race blythi.

Blythi Lesser Whitethroat

And just to add to the mix, going back to 20th October 2000, the bird below was caught. Unfortunately, a feather for DNA analysis doesn't exist, so we may never know what it really was. However, whilst its warm upperparts may suggest blythi, this was a big bird, with a tail length of 65mm, and a very 'blunt' wing. Birds from Mongolia very much resembling this bird have been DNA-tested and identified as being of the race margelenica.

Margelenica Lesser Whitethroat?

Some interesting controls from the autumn were:

• Juvenile Chiffchaff ringed at Nanjizal on 14/7/20113, recaught at Squire's Down (Dorset) on 21/9/2013
• Young male Firecrest ringed on St Agnes (Isles of Scilly) on 21/10/2012, recaught at Nanjizal on 5/10/2013
• Young Sedge Warbler ringed at Nanjizal on 3/9/2013, found dead the next day at St Ives 

So with nets now down for the autumn, some of the notable ringing totals include a top five of:

• Chiffchaff - 701
• Blackcap - 588
• Sedge Warbler - 538
• Chaffinch - 244
• Willow Warbler - 165

impressive totals of:

• Grasshopper Warbler - 54
• Yellow-browed Warbler - 15
• Firecrest - 10

and some rarities:

• Subalpine Warbler - 2
• Wryneck
• Aquatic Warbler
• Marsh Warbler
• Dusky Warbler
• Cirl Bunting

First Siberian Chiff of the winter?

With a hint of cold weather it was time to start poking round sewage works again and this morning we tried a new site for us, Gwithian, where it's nice and easy to net. Six nets in an open rectangle nicely cover the small site and although we only caught 18 birds, 10 of these were Chiffchaffs.

Of the 10 Chiffs, most were rather normal-looking, but one bird did look rather eastern... It's possible this is just a rather bright tristis Siberian Chiffchaff and it certainly called like one when released. But it does have quite a lot of green tones on the mantle and flight feathers, so not the most straightforward.

In comparison, all of the other birds looked more like the one below which was interestingly already ringed. We won't get the details on this bird for a while, but the ring was issued to East Dales Ringing Group in North Yorkshire, so a nice green collybita it is. Supposedly a photograph never lies, but check the difference in plumage tones in these two pics of the same bird: top a fancy DSLR and bottom my iPhone. Not surprisingly the DSLR looks to be a truer reflection of what the bird should look like!

More colour-ringed gulls

The weather is looking a bit more promising for the weekend, so hopefully we'll have some ringing news of our own shortly... But in the absence of calm days, there's always the fall-back of looking at gulls! After misjudging the tide at Hayle estuary yesterday, Copperhouse Creek was my only option, and I was greeted by this rather sleepy-looking Norwegian Black-headed Gull.

J4U4 was ringed as a chick back in 1991 near Stavanger (Norway) so is a very impressive 22 years old! It has been seen at Radipole Lake (Dorset) in February 2005 and was then recaught and colour-ringed as a breeding bird in Norway in April 2012, which then guaranteed a few more sightings. It bred locally in Norway in 2012 and was then not seen until January 2013 when it was on Hayle estuary. It was seen again in February before returning again in October 2013 and still there yesterday, so it'll be interesting to see if it's a regular wintering bird in Cornwall.

J4U4 in breeding plumage in Norway in May 2012

Interestingly, most birds from this Norwegain study head to Scotland and northern England, so a regular Cornish bird is very unusual.

This map shows the finding locations of birds from the Norwegian study,
showing how exceptional J4U4 is in its choice of wintering site.

A quick stop at Stithians Reservoir then also reunited me with a bird we'd ringed in Falmouth over the summer: W:032. It had been seen at the reservoir a couple of times already, but nice to catch up with one of your own birds away from home!

Thanks to Nils Helge Lorentzen for providing the details on the Norwegian bird so quickly, but note that these can now also be reported online here, with details instantly available! Thanks also to Alf Tore Mjøs for letting me steal his photo of J4U4 in full summer attire.

Mauritania Sedge Warbler and a Cormorant caught in the act

We recently received a whole bunch of reports back from BTO of birds we'd either ringed or recaught ourselves. The map below shows the spread of these reports and gives a good overview of where the birds we're ringing/seeing are coming from and going to. The map below shows birds ringed by us found elsewhere (in red) and birds ringed elsewhere recaught/seen by us (in blue), and you can zoom in to see more detail. Clicking on a line will also give you the full details for the movement: species, dates, places...

View Recent recoveries 2013 in a larger map

The furthest movements are a Sedge Warbler ringed at Gunwalloe recaught by French ringers 2400 miles away in Mauritania and a Polish-ringed Mediterranean Gull seen on the Hayle estuary (along with a Channel Islands Herring Gull). The movement to Mauritania is expected as this is where Sedge Warblers go, but is still only thew second from Cornwall to Mauritanis, with fewer than 25 BTO-ringed birds found there!

Other long-distance movements include Storm Petrels in all directions, with two birds to Skokholm Island (expect more from here as ringing has started a fresh here) and birds recaught from the Channel Islands and Co Wexford. We've also now got all the details back on the various colour-ringed Kittiwakes now breeding in Cornwall (more info on these here). These are all from the same French colony, but the interchanges are proving pretty fascinating!

View Recent recoveries 2013 in a larger map

A bit closer to home, a couple more of our colour-ringed Herring Gulls have been seen. Another bird from Falmouth visited Stithians Reservoir and a bird from Rinsey Cliffs was seen on the beach at Marazion. These birds all have a blue ring with code W:000 to W:999 so keep an eye out for these around the coast or at any gatherings of gulls. Another of our colour-ringed birds reported was a Cormorant caught in netting whilst stealing fish from an inland fishery, but was happily untangled and released unharmed. Wonder if it's learnt its lesson??

We don't have a photo of Cormorant TAH caught at the fish farm,
but here's TAB also ringed on Mullion Island

One final interesting movement is a Sedge Warbler ringed at Nanjizal and then recaught five days later at Gunwalloe, almost directly due east. We've also had recent reports of some of our Sedge Warblers moving north in autumn, so I wonder if these are actually heading out of the country somewhere further east and not directly or through the Isles of Scilly as expected...