Special delivery

Common Pipistrelle in the letterbox - it beats junk mail for sure.

Something other than birds, for a change - I wanted to share this image as, for me at least, a close-up look at a live bat in daytime is (bar the odd rehabilitated individual) a novel experience. When we were up in Norfolk the other weekend my daughter Ava came running in to say that she'd found a bat in the letterbox - actually a wooden box behind an external door used to catch delivered mail. With open access from outside, I originally assumed that this pipistrelle thought it was a good place to roost; it appears to be a Common Pipistrelle Pipistrellus pipistrellus based on the dark face and ears which contrast with the brown fur. However, it later climbed out of the box, and eventually we found it lying on the garden path; it died shortly afterwards, its ill health presumably being the reason for the unusual choice of roost site. Other pipistrelles continue to hunt over the garden, fortunately - we will put up a special box for them shortly.

Plan B

It wasn't to be - but then I half suspected that, after seven days, the Temminck's-cum-putative Long-toed Stint at Weir Wood Reservoir, East Sussex, might just move on overnight. So I waited on news before going - and waited, and waited. Had the bird stayed, it would have been too important to ignore, a much wanted Western Palearctic tick. But to be honest, I could also have done without slugging across the London Area in the morning rush hour to catch a glimpse of the tiny peep at a range of 400 metres. So with no sign at all of the bird today, it was off to the Lea Valley instead ...

As it flew in, this Hobby looked pretty good for an adult ...

... but note the slight brownish cast to the upperwings and the tail pattern and colour, suggesting a one-year-old bird with retained juvenile feathers. I don't expect to be seeing Hobbies of any age much later than this in London.

I called in at Rye House RSPB reserve, just beyond the northern fringe of London, for a couple of hours for today's birding fix. I was craving waders, which are largely absent from my Rainham Marshes patch at present with ongoing problems managing the water levels and habitat. There isn't a huge amount of suitable scrape at Rye House either, as the sum total of three Green Sandpipers and a Common Snipe demonstrates, but it was a chance for a bit more photography and a digiscoping practice session with some new kit (results to be uploaded separately in due course).

One of three Green Sandpipers at Rye House RSPB today.

A fly-over Siskin was an early-ish arrival, while departing migrants included Yellow Wagtail and a late-ish Hobby. At first glance the latter looked like an adult, but examining the photos more closely it looks better for a second-calendar-year bird - note the tail pattern and colour in the photos above, and also the brown wash to parts of the upperwing.

The day ended in similar fashion to yesterday, with breaking news of another mega - this time a Sandhill Crane at Loch of Strathbeg, Aberdeenshire. After last week's reports of a bird further south, and the strong winds two days ago which hit northern Scotland (where my brother was attempting to camp), it is tempting to speculate that this must be a second individual. With another in Finland which was then refound in Estonia, that's potentially three so far this autumn in the Western Palearctic. Whatever next? To find out, check back in 24 hours ...

Juvenile Sabine's up close

One of the two juvenile Sabine's Gulls at Sturt Pond, Milford-on-Sea, today.

Several strong Atlantic depressions, notably the tail-end of Hurricane Katia which hit last week, have bestowed a bonanza of exciting birds on Britain and Ireland in the last 10 days or so. The main headline-makers have been the Yanks on Scilly, notably Northern Waterthrush, Black-and-white Warbler, Red-eyed Vireo, Solitary Sandpiper and now Baltimore Oriole, but another significant weather-related phenomenon has been the widespread appearance of Sabine's Gulls. A few have even made it far inland or into the North Sea, and there was a staggering total from Bridges of Ross, Co Clare, of something like 830+ in one day last weekend. Has that ever been bettered in Ireland or Britain?

Juvenile Sabine's is beautifully marked, with pale edges and dark subterminal borders to its mouse-grey upperpart feathers giving a distinctive scaly appearance. Note also the narrow white primary tips and black tail band.

There was an adult Sabine's in London just over a week ago, on King George V Reservoir in the Lea Valley, but having not managed to get there before it left, I decided to get my fix today. Two juveniles on the Hampshire coast won the toss over an adult at Grafham Water in Cambridgeshire, so I headed down the M3 and arrived just in time to catch them both. Within minutes, one bird had done a bunk and the other became restless, absconding for short periods, but when it did settle temporarily it showed very well indeed.

The diagnostic black, white and grey 'triangle' pattern changes the bird's appearance completely in flight.

It's easy to forget how small and dainty these pelagic gulls actually are. Alongside Black-headed Gull they look positively diminutive, at times almost like a marsh tern on steroids with their pale foreheads and dusky cap and nape. The upperparts are also strikingly dark in juveniles, with pale feather edgings giving a smart, scaly appearance. Despite the body mass disadvantage, the one bird that lingered today showed aggression twice towards Black-headed Gulls before eventually flying off inland (though both apparently returned later in the day).

Juvenile Sabine's Gull with a single adult Mediterranean Gull among numerous Black-headeds.

Keeping the Sabine's and some 300+ Black-headed Gulls company were 12 Mediterranean Gulls (all adults bar single first-winter and second-winter birds), a lone Common Gull, about 15 Herring Gulls and two Great Black-backed Gulls (adult and juvenile). A Little Gull had apparently dropped in earlier on and doubtless a Lesser Black-backed Gull or two would have been in the area, meaning that a probable total of at least eight gulls species would have been frequenting the site today.

On the way back to London rumours strengthened that the so-called Temminck's Stint at Weir Wood Reservoir in East Sussex definitely wasn't one. By the time I walked back indoors the Least Sandpiper theory had also been shelved, the bird now mega-alerting as a Long-toed Stint. There's always tomorrow ...

Surf's up: whipped up by more strong westerlies, the sea pounds the beach at Milford-on-Sea.

Cabot's Tern: an update

The essential Dutch Birding paper is also available as a PDF on the Birding Frontiers memory stick.

Thanks to Martin Garner, David Callahan and Tristan Reid for some useful follow-up on my last post on Cabot's Tern, that recent BOU TSC-recommended split from Sandwich Tern.

I mentioned that Martin was lead author on the essential ID paper for this Nearctic tern that was published in Dutch Birding back in 2007, and should add that in addition obtaining the back issue of that journal, the same paper is also available as one of 25 articles on the excellent value Birding Frontiers memory stick (order for just £11 including p&p here). You'll need Acrobat Reader (download free) to view the material, which includes a superb plate of Cabot's (aka American Sandwich) and Sandwich Terns by Ian Lewington.

Apparent Cayenne Tern Sterna acuflavida eurygnatha (Cemlyn Bay, Anglesey, 8 June 2006). Note the dull orange-yellow tone to the bill, the same colour also being visible on the knees and feet.

Meanwhile, David Callahan reminded me that, although it's not yet on the BOU's British list, there is a strong British claim of the eurygnatha subspecies of Cabot's Tern, known as Cayenne Tern. This is in addition to the accepted record of nominate Cabot's Tern, a recovery of a ringed first-winter found dead in Herefordshire in 1984, so both subspecies have apparently made it to Britain. The Cayenne Tern was present at the Welsh tern hot-spot of Cemlyn Bay in June 2006, and best photos I've seen of it were taken by Tristan Reid (visit his website here).

Apparent Cayenne Tern Sterna acuflavida eurygnatha (Cemlyn Bay, Anglesey, 8 June 2006). Cayenne Tern is distributed from the Caribbean southwards along the Atlantic coast of South America; Caribbean birds are said to have the yellow-orange bill toned greyer in the central and basal part (Olsen and Larsson 1995), rather like this.

Tristan tells me that, subsequent to seeing and photographing the bird, he sent images to Floyd Hayes, who has done extensive studies on this form in the Bahamas. Floyd was of the opinion that the bird fitted Cayenne Tern and said that, had he seen it in his study areas, he would have recorded it as such. I'm not sure that pure adult European Sandwich Tern has ever been known to have a yellow bill, although I have once recorded a juvenile with a strongly yellow bill (see British Birds 82 (1989): 414).

Apparent Cayenne Tern Sterna acuflavida eurygnatha (Cemlyn Bay, Anglesey, 8 June 2006). From this angle the bill appears more strongly yellow. In some Cayennes, the upperparts can apparently be slightly darker grey.

In a quick trawl of the literature I haven't seen any obvious comment on Cayenne Tern showing yellow on the knees, which the Anglesey bird clearly does. Is this problematic, or just not well documented? It seems logical that a bird with variably dark tones to the bill might have something similar happening with its legs too, but the closest mention I can find to this so far is "[Legs and feet] black with black or yellow soles; underside of heel also yellow in some birds. Foot occasionally all yellow or mixed black and yellow" (Shealer 1999).

Feedback on this or the current status of any claim for Cayenne Tern with the BOURC would be welcome - as a potential split in its own right, eurygnatha has the potential - if the record is accepted - to become a new British bird. In the meantime, thanks to Tristan Reid for allowing me to use his informative images.

ADDENDUM
Thanks to Ed Smith for drawing my attention to an image from Venezuela of a Cayenne Tern which, like the Cemlyn Bay bird, has similarly yellow areas on the legs - perhaps this is more a feature of this form than illustrations have hitherto suggested. There has also been recent discussion on ID-Frontiers of the identity of a Sandwich-type Tern photographed in Chicago, Illinois, USA, in September 2010 - Greg Neise makes a reasonably strong case for this bird being a European sandvicensis rather than a North America acuflavida (see here), but I guess that's one the committees will be wrangling over for some time.

* NB Watch out for a review of the Birding Frontiers memory stick in a forthcoming issue of Birdwatch.

References

• Olsen, K M, and Larsson, H. 1995. Terns of Europe and North America. Christopher Helm, London.
• Shealer, D. 1999. Sandwich Tern (Thalasseus sandvicensis), The Birds of North America Online (A Poole, Ed.). Cornell Lab of Ornithology, Ithaca. Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/405 doi:10.2173/bna.405

Unattainable armchair tick

One of the birds below has just been added to the British list, the other is a Sandwich Tern. Can you tell them apart? Quite possibly not, but at least their mothers can - and have apparently done so for countless millennia, according to genetic research which has led to the BOURC's recommendation to split Cabot's Tern Sterna acuflavida (for a summary of other important BOURC taxonomic announcements, see here).

The phrase 'armchair tick' will be familiar to many, and on paper at least this is what Cabot's Tern should be. It has occurred in Britain, and also in The Netherlands. Unfortunately, however, the records involve ringed birds that were picked up dead - the British individual somewhat bizarrely by a Forestry Commission ranger at Newhouse Wood, Herefordshire, on 28 November 1984, and the Dutch bird prior to that on 23 December 1978 in Zeeland. Both were found as first-winters, and had been ringed as chicks at different locations in North Carolina, USA. So the only two Western Palearctic records - so far - involve corpses.

More attention will surely be paid to Sandwich Tern identification in future, even if it will prove testing. The most comprehensive paper is by Martin Garner, Ian Lewington and Jason Crook, and was published in Dutch Birding back in 2007 (29: 273-287). It goes into great detail on the separation of Cabot's (or American Sandwich Tern as it is known in the paper) from Sandwich Tern; less problematic would be the appearance of the variably yellow-billed Cayenne Tern, which has also been included within Cabot's by the BOURC (subspecies eurygnatha).

No time or space to go into detail here on the separation criteria for the two main protagonists - you can dig out your old Dutch Birding or, failing that, read a summary in Dutch here, or hope that those kind birders in Holland upload free PDFs of the issue in due course (as they have done for many previous volumes). Better still, you can subscribe to this excellent publication, and then next time you won't miss out.

But back to my original question: the answer is that the Cabot's Tern is the top photo, with the Sandwich Tern immediately below it. They were both taken this year, respectively on 1 August in Yucatán, Mexico, and 25 June at Rye Harbour NR, East Sussex. Compare, for example, structure (including bill) and the extent of dark pigmentation in the wing-tip. And to finish with, here's an adult and juvenile Sandwich Tern from Minsmere RSPB, Suffolk, on 1 July 2009 - juvenile plumage probably being the most distinct between the two species.

Hollywood's take on birding - The Big Year

Here's the official trailer for the Hollywood movie The Big Year, based on the 1998 book of the same name about yearlisting in North America. You'd almost have to guess it was about birding, so thin are the references as Steve Martin, Jack Black and Owen Wilson goofball about to the amusement of their wives. It doesn't look immediately faithful to Mark Obmascik's classic read, but I'll reserve judgement until it goes on release.

Azores tour makes the national press

Sunday Express columnist Stuart Winter knows from personal experience how thrilling the birding is on the Azores in October, especially on Flores where he struck gold last autumn. In this cutting from yesterday's paper he recalls the experience and flags up this autumn's Transatlantic Vagrants tour, which I'm leading from 15-23 October - click here for full details. Thanks for the mention, Stuart.