Friday, 29 April 2011

On the move

A flock of Bar-tailed Godwits reorients eastwards along the Thames at Rainham.
It was a good session on the patch at Rainham this morning, with yesterday's weather forecast hinting at the possibility of passage along the Thames today. The wind seemed more northerly and the atmosphere drier than forecast, but that didn't stop good numbers of Bar-tailed Godwits from passing through the London Area. These birds are 'overspill' from the regular mid-spring passage up the Channel, which yesterday reached epic proportions - Portland logged a record day count of just over 6,000 birds, far eclipsing its previous highest spring total of 4,266 and record day total of 2,500. Further east along the south coast, Dungeness Bird Observatory also hit the headlines with a record-breaking 7,317 Barwits moving east.

With the vast majority of birds heading straight up the Channel and the North Sea, it takes a favourable wind, poor visibility and preferably rain for London to derive benefit from such movements. The first two factors came into play today, which meant I recorded a personal best of 44 Barwits at Rainham this morning. Always great to see these birds in spring, when they vary in plumage from washed-out greyish-brown to the deepest brick-red of just about any shorebird.

This Hobby was presumably new in on the tip, and was later joined by several others.
Other migrants this morning included Hobby, Eurasian Curlew, two Common Sandpipers, six Common Terns, Yellow Wagtail, three Northern Wheatears and a skulking Grasshopper Warbler far more easily heard than seen.

Three of a kind: this adult male Northern Wheatear ...

... and presumed first-summer male (note incomplete mask and slightly browner wings) ...
... kept company with this female along the sea wall at Aveley Bay.

Far less showy was this Grasshopper Warbler, which never fully emerged from cover.

I checked the barges car park in case more godwits were roosting over the high tide, but instead came away with two third-calendar-year Yellow-legged Gulls.

One of two second-summer Yellow-legged Gulls in the barges area. No adults for more than a month now.

As I drove away from the site, past the new marshland landscaping along Coldharbour Lane, I noticed a small bird distantly at the edge of a pool. A quick check revealed it to be my first White Wagtail of the year, albeit one missing half of its tail.

This White Wagtail (a first-year male?) looked pretty dapper, the lack of a full tail excepted.

Monday, 25 April 2011

Hunting the Sprawk

A male Eurasian Sparrowhawk makes a low pass over West High Down in search of prey ...
I seem to have spent quite a few hours watching raptors this spring, with Eurasian Sparrowhawk perhaps the most frequently observed species after Common Buzzard. I've photographed quite a few 'Sprawks' in the process, but none as closely as this male on the Isle of Wight last week. It came past me in a flash as it tried to flush up pipits and other passerines from the short turf of West High Down. Amazingly, it then landed close by and allowed a close approach until it launched off again in pursuit of its target - a presumably terrified Common Chiffchaff.

... before staking out a migrant Common Chiffchaff in a cliff-top bush.
It watched the bush in which the warbler took refuge, eventually taking off in pursuit of its intended victim - only to be out-manoeuvred in a dramatic near-vertical ascent by the 'Phyllosc'. So nothing doing this time, but an impressive interaction to observe nonetheless.

The hawk launches in pursuit of the warbler, which spectacularly evades death at the last minute.

Sunday, 24 April 2011

Rufous on Wight

Swallow with rufous-washed underparts (West High Down, Isle of Wight, 20 April 2011): note the striking colour of the underparts, and that the undertail coverts seem almost as dark rufous as the face.
Just back from a week away with intermittent web access, so apologies for the late updating. First up is this interesting-looking Barn Swallow, which I found at the Needles New Battery, high up on the western tip of the Isle of Wight, on 20 April. Initial thoughts that the rufous-washed underparts might suggest an American bird can be dispelled by the dark rufous face pattern and, particularly, the thick blue breast band, which confirm it as from the Old World (in American erythrogaster, a likely split, the breast band is narrow and broken in the middle).

The thick blue breast band and dark rufous face rule out the North American form erythrogaster, which also typically shows strongly rufous-washed underparts.
So is this bird just a variant nominate rustica, or from a population from elsewhere in the species' range? Having appeared during a period of prolonged easterly winds in spring, it could potentially be a transitiva individual on appearance - this subspecies from the Lebanon, southern Syria and Israel is described by BWP as having "rusty-pink or rufous-buff" underparts, both of which could perhaps be applied to this bird. But ...

The same bird in flight, showing that the rufous washing extends fully over the underparts and underwing coverts.
... perhaps the most likely explanation can be found in another passage in BWP: "Birds from transition zones from nominate rustica into transitiva in south-west [surely south-east?] Europe and Asia Minor ... are strongly variable individually, and also outside these zones some populations are paler or darker than others, while a few rusty-bellied birds occur in almost all pale-bellied populations and vice versa." The same passage goes on to score geographic populations according to underpart colour, adding that the "proportion of transitiva-type [birds is] everywhere below 10%".

As this individual (a male) was also associating with a 'normal' adult (a presumed female), the likelihood is that it is a rufous variant rustica, perhaps from farther afield, but possibly more locally given that such individuals can crop up anywhere. I'd welcome comments from anyone who has seen or photographed similar such birds in Britain - I can't recall seeing one in Western Europe this richly coloured on the underparts.

Tuesday, 19 April 2011

South coast seawatching

St Catherine's Point at the southern tip of the Isle of Wight: prime seawatching estate.
Greetings from the Isle of Wight, home for a week in the run-up to Easter. This is family time with birds fitted in as and when, but I have finally managed to tick off a legendary birding site: St Catherine's Point. The quickest of glances at a map will immediately reveal why this is such a good place at migration times, but it is legendary in my book for one particular reason: a fly-by Wallcreeper on a seawatch!

Common Buzzard at St Catherine's Point. By far and away the commonest raptor on the island.
There has been a dearth of Wallcreepers this week, but the seawatching has certainly been worthwhile. For example, here are this morning's totals from my stint at the lighthouse from 07:35-10:10, with the great majority of birds moving east up the Channel: 3 Shelduck, 118 Common Scoter, 23 Gannets, 12 Fulmars, 3 Cormorants, 14 Whimbrel, 1 Arctic Skua (pale adult), 1 Mediterranean Gull (first-summer), 2 Common Gulls, 3 Kittiwakes, 23 Sandwich Terns, 19 Arctic Terns, 1 Little Tern, 3 auk spp, plus 2 Yellow Wagtails and, most unexpected of all, a Kestrel 'in off'.

Most passing seabirds were way out of photographic range, bar this Gannet ...
... and (only just) this pale morph adult Arctic Skua.
A fly-by ring-tail Hen Harrier yesterday near Brook Down was another surprise, but the clear skies and high temperatures mean that these easterlies have so far produced few passerine surprises. More anon ...

Thursday, 14 April 2011

Snipe up close

Adult Common Snipe wing-stretching: note the width of the white trailing edge on the secondaries, as well as the broader white than dark axillary bars and split white 'snowdrop' tips to the upperwing coverts.
Common Snipe is an intriguing species. It's a bird I see quite often, yet rarely very well or in the open. When I do, the more I look the stranger they seem, full of interesting plumage marks and features. Through the lens, when literally focused on composition, such plumage subtleties are less easy to grasp, until I review images later on a large screen.

Up to five Common Snipe were bathing and resting in close proximity.
I took these shots at Rye Meads RSPB, in the Lea Valley in Hertfordshire just north of London, almost a week ago, but have only just found the time to put them up online. I wish the birds on my regular round at Rainham performed like this a bit more often ...

In bathing mode - of dozens of shots, this was about the only one where the bird kept its head still, but 'rolled' its body to allow me to capture movement and water droplets in the air.
On the Birdwatch reader trips I lead to the Azores every October, we always keep a lookout for Wilson's Snipe - an annual Nearctic vagrant in autumn which now numbers more than 100+ records there (including one of a displaying bird). If you're wondering how so many have been identified in the islands, the answer is ... they shoot them! Field ID and obtaining photos is far harder, for obvious reasons, but twice now I've flushed birds with the narrower white trailing edge indicative of Wilson's, one of these birds also being rather 'colder' in plumage tone. On both occasions, however, the snipe flushed far away, landing in inaccessible areas where they could not be easily pursued ... maybe next time.

Give those tail feathers a good preen ... another fascinating thing about Common Snipe is that they normaly have 14 tail feathers, but can have anything between 12 and 18. Go figure!

Saturday, 2 April 2011

Fudged duck

Presumed hybrid Ferruginous Duck x Common Pochard on the boating lake at Alexandra Park this morning. Note the red eye, bill pattern, darker breast and tell-tale grey in the wing (white in Ferruginous Duck).

The same bird as above. The undertail coverts can't be seen here, but were white sullied darker.
Had a short walk around the north end of my Alexandra Park patch this morning, and found this Ferruginous-type hybrid consorting with the Common Pochard flock. From some angles and in a certain light it looks more like a Ferruginous Duck, but the wrong features are readily apparent - for example the darker breast, sullied white undertail coverts, bill pattern, eye colour and grey in the wing. Nonetheless, always interesting to look at these birds and get to know them better. This is the third such Aythya hybrid I've found in the park this winter, though it is clearly more Ferruginous-like than the other two.

The real deal, for comparison: this female Ferruginous Duck was a one-day bird in south London at Burgess Park, Camberwell, last November. Note the head shape, bill and uniform breast/flanks.

Friday, 1 April 2011

Uncommon gulls?

Second-calendar-year Common Gull Larus canus (Rainham, Greater London, 11 March 2011). As well as the dense brown spots, bars and chevrons on the head, neck and flanks, note also the obvious patterning on the uppertail coverts. This individual, uniquely among all the first-winter-type Common Gulls I've photographed recently, shows strongly barred Eurasian Curlew-like axillaries, suggested by Olsen and Larsson 2003 as indicative of heinei.
I spent the afternoon on Rainham tip today, but it was a fairly fruitless endeavour. The hordes of winter gulls present less than a month ago have now largely dispersed, and though at times several hundred gulls were in the vicinity, they rarely came in to feed today. Single second-calendar-year Caspian and Yellow-legged Gulls were the only noteworthy larids other than the common five species. Even Common Gull itself was represented by just a single fly-over adult in breeding plumage - a far cry from previously.

This last species has become a focal point in recent weeks. I noticed a post on Martin Garner’s blog (see links below) back in December about Common Gulls of the subspecies heinei, in which he flagged up the possibility that this Russian form might occur here more often than is suggested by the very few records (which appear to be related to ringing recoveries). When we hosted the Rainham gull day in early March Martin again talked about heinei and ran through characters indicative of this form.

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