Tuesday, 22 May 2012

Bona fide gull

First-winter Bonaparte's Gull at Barking Bay: note the diagnostic white under-primaries with black trailing edge.
Black bill aside, there is something subtly different about the head pattern of Bonaparte's cf Black-headed.
I was delighted to get a phone call from Rich Bonser last Saturday to say that he was looking at a Bonaparte's Gull on the Thames at Crossness. Less pleasing was the fact that, instead of me being two miles up the road at Rainham (as I often am on a weekend), I was actually some 420 miles away in Edinburgh, spending the weekend representing Birdwatch at the first-ever Scottish Birdfair. Thereafter I endured an anxious three days until returning to Stansted Airport on Monday evening, hoping that the bird would still be there.

Having made excellent time from Stansted to Barking, a nervous 40 minutes followed as I searched in vain for the bird while the light slowly began to wane. Even flushing a Ring Ouzel failed to raise a smile, and the news from John Archer and Rich Bonser who were looking across the water at Crossness was also negative. Then, suddenly, there it was - on the water's edge beyond the vast expanse of mud in front of me. I'd already checked that stretch repeatedly without luck; the bird must have dropped in while I was scanning further along. Though very distant, there was no mistaking the wing pattern, black bill and diminutive size. I struggled to get usable images at that range with only a 300mm lens and 1.4x converter, but these record shots hopefully convey an idea of the bird's distinctive appearance.

This seems set to become the first London record of the species, after rumblings suggesting the only currently accepted claim is unlikely to survive a review . Many of us gullwatchers on the Thames (and elsewhere in London) have looked for this species, but the prize goes to Rich for nailing it, and for cementing Crossness's reputation as (along with Rainham and Beddington) one of the three top larid spots in the capital - it has previously hosted Franklin's Gull and (if I recall correctly) 10 Sabine's Gulls together after the 1987 'hurricane'.

Thanks also to Bob Watts, Roy Beddard and Paul Hawkins for news updates and local gen on the bird.

Wednesday, 16 May 2012

You wouldn't Adam and Eve it

London's 10th Melodious Warbler skulks this morning within a stone's throw of Leyton Orient's ground.
When I lived in east London some years ago I did a regular commute by car through Leyton, queuing daily in the traffic past Leyton Orient FC's ground. On all those hundreds of occasions I doubt I ever saw anything more remarkable than a Magpie or a Mistle Thrush in such a limited urban environment. Today I stood on the pavement in the same spot, with baffled drivers and passers-by gawping at me and a small crowd of others, as London's 10th Melodious Warbler sang from within cover. What a turn-up for the record books.

The bird gives a brief view in flight as it momentarily breaks cover. Only twice did I glimpse it fully in the open.
The bird rarely showed during the limited time I had available before work, but the few glimpses and the often-heard song - a manic, rambling chatter that was far from melodious - were enough to confirm the identification. What a brilliant, out-of-the-way find by Stewart Fisher, who presumably picked it up on song. There are much better pockets of habitat not too far away, so presumably this bird was newly arrived. I missed one in Regent's Park back in 2000, and today's is only the third in over two decades in London (inland records of this southern European overshoot are unsurprisingly rare). It was my 281st species in the London recording area.

Previous London records of Melodious Warbler:
12-13 August – Rye Meads/Nazeing
1964 10 August – Navestock
1973 20 September – Romford
1981 26 May – West Thurrock
1983 11 June – Ruxley GP
1987 30 April-2 May – Croham Hurst GC
1990 5 May – Barn Elms Res
2000 23 August – Regent’s Park
2004 1-2 October – Fairlop CP*

* No description received of this bird by the London Records Committee but it was accepted by the Essex Birdwatching Society (Fairlop CP falls in both recording areas) and published in The Birds of Essex by Simon Wood (Helm, 2007). See also London Bird Report 56: 203.

Sunday, 13 May 2012

A declining migrant

Singing male Wood Warbler Phylloscopus sibilatrix, Alexandra Park, London, 12 May 2012.
Spring has been rather late this year for many species, so even with a third of May over I was still hopeful of some migrants moving through my local patch of Alexandra Park yesterday morning. But plans for a sky-watch from the viewpoint we optimistically term the 'obs' were abandoned within two minutes when I heard a distinctive but all too infrequent song coming from the tree-covered slope below: Wood Warbler!

The bird occasionally showed well  as it clambered about the mid and upper storeys of its favoured oak.
Alexandra Park has something of a track record for this species, although it is not annual and records sometimes involve silent migrants in autumn. I rang around local birders immediately and, after it initially went missing, the bird reappeared to sing intermittently in oaks and birches at the south-west corner of the pitch n' putt course. Andrew Gardener, Bob Watts, Gaz Richards and Alan Gibson all managed to see it well before it went AWOL mid-morning.

As well as its evocative trilling song (I recorded the above unedited sequence on my iPhone), the bird also uttered the alternative, somewhat melancholy, piu-piu-piu series of notes. At one point it gave occasional single piu call notes, the first time I have heard this as a 'solo' vocalisation, and a good learning opportunity as a potential way to pick up non-singing migrants in future.

Wood Warbler has become something of a rarity in the London Area over the years, mirroring the national decline of the breeding population. Whereas in 1994 there was one breeding pair, 23 singing birds on spring passage and 20 more in autumn, the total number of sites where the species was recorded during the five-year period 2004-2008 were 1, 10, 16, 8 and 7 respectively (London Bird Reports passim).

Here the bird can be seen successfully reducing the park's caterpillar population by one.

Tuesday, 8 May 2012

Big day patch record

Two Grey Plovers drop in to Aveley Bay on their way north to the tundra.
For many years the first weekend in May was known as bird-racing weekend. For bird race, newcomers to birding (and North American birders) should read ‘big day’. I did a London bird race for many years as part of a team of four, but since 2006 when we succeeded in setting a new record of 113 species, the pressure has been off to continue the tradition.

Bar-tailed Godwits have been a constant feature at Rainham recently. These birds were part of a 36-strong flock.

Sunday, 6 May 2012

Stunning site tick

One of the two Black-necked Grebes at Rainham on Friday 4 May. They didn't linger over the weekend.
Although Friday's trip to Rainham Marshes came to a premature end following the appearance of Dotterel elsewhere in the London Area (see previous post), it was shaping up to be an excellent day on the reserve. Aside from a wealth of waders which included 36 Bar-tailed Godwits, six Eurasian Whimbrel, Common Redshank, Greenshank, Oystercatcher, four Common Sandpipers, a Red Knot, two each of Dunlin and Sanderling, Northern Lapwing and 18 Ringed and four Grey Plovers, I had a rare site tick in the form of Black-necked Grebe - and not just one, but two stunning summer-plumaged birds. I can only recall two previous Rainham records, so this duo on Aveley Pools were apparently unprecedented. The species is a mainly scarce passage migrant and winter visitor in London and a rare breeder; high-magnification scope views across a windy reservoir tend to be the norm, but not so on this occasion.

The species is a passage migrant and winter visitor to London, with rare breeding records mainly from one site.
Unmistakable in breeding plumage, the American name of Eared Grebe seems inappropriate at other times of year.

Saturday, 5 May 2012

Unexpected trip

Good news and bad news. The bad news first: I had to abort a great day out at Rainham Marshes at lunchtime yesterday and give up what would almost certainly have been a new personal best day total for the site (well in excess of 80 species was on the cards - more of that in a separate post). The good news: a trip of Eurasian Dotterel was found on the Surrey fringe of the London Area at the emerging hot-spot of Canons Farm, Banstead.

David Campbell quickly texted out news of this superb find just after 2pm - congratulations to him, Nigel Sluman and Roy Weller for discovering Surrey's first record since 1884, and London's first for 18 years. I exited Rainham immediately and promptly ran into traffic on the nearby Dartford Crossing, before getting a clean run on the M25 and arriving at Canons Farm an hour or so later.

Thankfully, the Dotterel were still on show, though initially most of the birds were sitting in stubble and not overly showy. David was still on hand, as were Johnny Allan, Peter Alfrey and a surprisingly small crowd of onlookers; eventually the Dotterel got up and started feeding. I took these images from the public footpath along the side of the field, having seen that passing dog walkers and their charges were not alarming the birds in any way, and having checked with my fellow observers before approaching carefully. It was suggested that the flock comprised nine females and six males, though at least two of the duller birds may have been second-calendar-years (in which case perhaps they are not so straightforward to sex?).

Dotterel are a good find anywhere on migration. A rare breeder in Britain, it is thought that a high proportion of birds reach the breeding grounds without stopping (The Migration Atlas). Away from a very few regular (or formerly so) stop-over sites such as Black Peak Farm in Cambridgeshire and Pendle Hill, Lancs, inland birds are bordering on the exceptional, hence the absence of records in Surrey for 128 years. Only once have I been lucky enough to find a migrant, a single bird on Lundy, Devon, back in May 1991 when I was twitching the Ancient Murrelet there. The last London record closely matches this one, and involved a flock of 16 birds at London Colney on 7 May 1994; I wasn't able to get there then, so this grip-back has been a long time coming.


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