More Gull Action at Topsham Rec

17th May 2013 - Topsham

The Bonaparte's Gull hasn't been seen since Wednesday and frankly I'm hoping it might have moved on. I have sympathy for the few people still turning up to see it but I admit it'll be nice to have the place to myself again.

Perhaps as consolation, a first summer Little Gull has dropped in a couple of times, surprisingly an addition to my list for the site and the first one I've seen for a few years. The local Black-headed Gulls, delighted to have found something below even them in the gull pecking order, gave it a bit of a hard time and it didn't stay long. I wish they'd gang up and clear out the 'plastic' waterfowl as well - the 'farmyard' ducks and Mute Swans (sorry, I just don't care for them) and there were even a pair of Bar-headed Geese a couple of weeks back...don't get me started.

Meanwhile, some proper birds - further up the river, where the big gulls bathe and preen at low tide, things got interesting. I found this bird with the usual Herring Gulls.

I've become suspicious of apparent Yellow-legged Gulls and here's why.

Out of the water the bird showed a nice pair of pink legs; there was a hint of yellowish I think but nowhere near the bright yellow of a michahellis. So how about an argentatus Herring Gull? Maybe the grey is a little too dark but the wing pattern settles it.

There are two big white mirrors on P9 and P10, a lot of black on P8-10, black bar on P5 and obvious white 'moons' behind the black on P5-7. So, no pale tongues on outer primaries, no solid white tip to P10 and the black on P5 together fairly comprehensively rule out argentatus.  It also doesn't look like a michahellis with abnormally coloured legs since the large mirror on P9 and the white moons are also wrong. Reluctantly, because it's something of a cop-out, I've got to say It's almost certainly a hybrid, presumably with the genes of argenteus Herring and graellsii Lesser Black-backed. Looking closely at the primary pattern I'm pretty sure this bird is one I saw here on the 28th April. This is the second apparent hybrid at this spot this year - and I've only seen two 'safe' Yellow-legged Gulls in that time.

Roseate Terns and Sanderling

12th May 2013 - Exmouth

It seemed a good idea at the time - an early morning walk - before the crowds - on Exmouth Beach to photograph some terns. But the birds (mostly Common Terns, with a few Little, at least one Arctic and at least a half dozen Roseate Terns) were not really co-operating. They were all feeding in the shallow water over Pole Sand at the mouth of the Exe. As they were not getting any closer than a quarter of a mile off my Tern photography was not entirely successful.

This (much cropped) photo clearly falls into the category of 'record shot' - two Commons and one of the Roseates with Dawlish Warren in the background. The Roseate even looks a bit pinkish at this distance, they must have been gorgeous close up.

 Some compensation was present however, with this confiding Sanderling on the beach. A lot of breeding/summer type feathers among the grey and no sign of any retained juvenile coverts or remiges so presumably an adult on it's way to the High Arctic.

Bonaparte's Gull - again

4th May 2013 - Topsham

Yesterdays views and photographs of the Bonaparte's Gull were somewhat less than satisfactory. I popped down again for next morning's low tide on the off chance it was still around. I wonder if there's a rule with rare birds - be difficult to pin down/confirm at first, but then to give up as if saying 'OK, you got me - anybody else want a look?' A similar thing happened here with the Spotted Sandpiper a couple of years ago. So I wasn't too surprised when the Bonaparte's appeared and showed off when some bread was offered - courtesy of Martin Elcoate, who's even more local than me, he now has it on his garden list.

It was now fairly easy to pick out from the other small gulls in flight, it was just about the only bird in adult type plumage. Still, it wasn't easy to track with the camera and the light wasn't too bright.

The size difference compared to Black-headed was not great but usually obvious. The black hood was also more extensive - covering more of the neck. The grey of the mantle also looks a shade darker next to the Black-head.

Bonaparte's Gull

3rd May 2013 - Topsham

I don't expect much in the way of gull interest in May, plenty of resident Herring Gulls, a few local-breeding Lesser and Greater Black-backed and small numbers of 1st summer Black-headed. Still, it can pay to look, and it helps to be forewarned. Local birder Nick Potter reported a possible Bonaparte's Gull from the Bowling Green hide on Thursday, it was in the back of my mind on Friday morning as I wandered up the path by the Exe at the Recreation Ground. Virtually all the Black-heads are now first summer birds with obviously juvenile type wings and patchy hoods, I picked out the one bird with a complete hood and started wondering. The hood appeared to be blackish, no hint of brown, the bill looked thin and dark, now I really got interested. It stood beside a Black-head but didn't appear to be particularly small - maybe it just picked out the smallest available so as not to stand out? Everything looked good but I really wanted to see the open wings, so I waited for it to fly. Then it went, I got a couple of shots and my camera froze - dead battery. Of course, by the time I'd changed it the bird was gone. It could have been worse, at least I got the shots that clinched it, showing the pale, black-tipped primaries on the underwing. Not sure if I can really call this a 'find' but it's a very good bird for my patch.

A winter plumaged Bonaparte's had been seen occasionally in the area from October (found by Stephen Edwards here) through to January (including nice photo by Chris Townend here). Is it the same bird? Obviously the May bird has a hood as would be expected but the wings hold the answer I believe. That blackish strip on P9 and the tiny dark spots on the outer primary coverts (and possibly the alula, it's hard to be sure) very nicely match Chris's November photo. I think it's almost certainly the same bird. Incidentally, according to Howell & Dunn (2007) and Malling Olsen & Larsson (2004) those characters also strongly suggest that this is a 2nd summer (or 3rd calendar year, or 2nd cycle - take your pick, it's all the same age).

References

Howell, S.N.G. & Dunn, J.L. 2007. Gulls of the Americas (Peterson Reference Guides). Houghton Mifflin Harcourt.
Olsen, K.M. & Larsson, H. 2004. Gulls of Europe, Asia and North America. A & C Black.

Sedge Warbler

27th April 2013 - Highfield Farm, Topsham

 

Sedge Warblers are now singing in the marshes along the River Clyst. So intent on getting a good territory and attracting a mate they can be quite approachable - at the price of wet feet as the ground is so spongy and waterlogged. I took a few photos and made some sketches.

Tephritids and the feasibility of identification from photos

25th April 2013 - Topsham

I'm trying to catch up on work but still finding the time for a quick trip down the garden with my camera and tripod. Most of the insects visible and photographable right now are flies, one of the more colourful was this Tephritid.

This is Euleia heraclei (Linnaeus), sometimes given the common name of Celery Fly (Colyer & Hammond 1968). The larvae also leaf mine many other umbellifers including Hogweed (Heracleum sphondylium) hence the specific part of its name. This male was parading about on a nettle leaf waving his wings to attract a female. Although I was fairly confident I knew it, I confirmed its identity using the key in White (1988). The wing pigmentation is a little faint on this one and I wonder if it's not long emerged. It's quite a variable species, some are reddish-brown, others are dark brown to black (White 1988, Colyer & Hammond 1968). According to White (1988) the first is the Spring generation, the latter black form is the second late Summer generation. This one has a dark brown thorax and a black abdomen. The next two were both taken in April a few years ago.

These two are both females (from the shape of the abdomen) but are definitely Euleia heraclei - the wing pattern is diagnostic. They are presumably all the same generation but they differ markedly in colour. From discussions over at Diptera.info I suspect that, of the two colour forms, the black is the 'normal' one, the reddish brown is a 'Summer' variant.

As an aside I wonder just how many of 76 British species can be identified from photos. Many have distinctive colours and wing markings - in fact they're probably no more difficult than most Hoverflies. Looking at White's Handbook (1988); 22 species and all British genera are identified using his first  'Simplified key'. From a brief look, none of the characters used in the key appear to be impossible to see on photos. 

The remaining genera are keyed to species as follows:

Myopites - 2 spp. separated by wing pattern and abdomen.
Urophora - 7 spp. 4 separated by wing pattern, 3 spp. only by genitalia.
Platyparea - 2 spp. separated by wing pattern.
Rhagoletis - 3 spp. separated by wing pattern.
Trypeta - 3 spp. separated by wing pattern, thorax pattern and head bristles.
Vidalia - 2 spp. separated by wing pattern, thorax pattern and head bristles.
Cerajocera - 3 spp. 2 only separated as larvae/pupae*
Chaetorellia - 2 spp. separated by wing pattern. 
Terellia - 6 spp. 4 separated by wing and thorax pattern, 2 by size and proportions.
Oxyna - 3 spp. separated by thorax bristles.
Paroxyna - 7 spp. separated by wing, thorax and leg characters.
Campiglossa - 2 spp.separated by wing, thorax and leg characters.
Dioxyna - 1 spp. separated by wing, thorax and leg characters.
Tephritis - 10 spp. separated by wing pattern and bristles.
Trupanea - 2 spp. separated by wing pattern.

*Cerajocera is now included as a subgenus in Terellia; the two difficult spp. ceratocera and plagiata can now be separated using the key in Korneyev (2003).

I realise the exact arrangement of genera and species has changed but the argument is still valid. Of the British total of 76 spp.it appears that 3 can only be separated by terminalia examination, 2 spp. can only be separated on the basis of size and relative length of oviscape (female egg-laying tube). Given that the egg-laying apparatus of Tephritids is often quite easy to see, it's possible that identification is quite feasible. The remaining 71 spp. are, in theory, identifiable based on wing pattern, pattern of thorax, and head and leg bristles. Bristles can be tricky to get right on such small flies but not impossible; the wings and thorax are relatively straightforward. I think I need to find more Tephritids.
 

References

Colyer, C.N. & Hammond, C.O. 1968 Flies of the British Isles Warne.
Korneyev, V.A. 2003  New and little-known Tephritidae (Diptera, Cyclorrhapha) from Europe. Vestnik Zoologii, 37(3): 3-12.
White, I.M. 1988 Handbooks for the Identification of British Insects Vol.10 Part 5a: Diptera: Tephritidae. Royal Entomological Society.

Return to Macro

20th April 2013 - Topsham

When I'm out and about in 'birding mode' my approach to photography is simple. I carry a modest lens - just an old Nikon 300mm f/4 with a x1.4 teleconverter - which is a compromise between weight and magnification. I almost never use a tripod for birds - I can usually hand hold at the shutter speeds needed for moving birds. And of course, I scan the middle distance and the sky, not the ground at my feet. Photographing insects is so fundamentally different that, as well as different equipment, I almost need a quite different frame of mind. I suppose It's just like switching a camera's mode option from 'birding' to 'macro'. Except it's more complicated: set to manual focus, minimum aperture, lowest ISO, mirror lock-up and cable release. Of course I also need a different lens - I use a Sigma 180mm f/3.5 macro - and a sturdy tripod and head - a Uni-loc with a Manfrotto Proball 468 RC4; which is one of the reasons I tend to walk slow and not far when looking for insects.

It's been far too long since I did any macrophotography so I wondered if I'd have to learn it all again. Yesterday I dusted off my macro lens and tripod, and tried to remember the techniques.

At this point I remembered two of the problems that used to make life difficult: bright sun and wind. Insect cuticles are often shiny - not so much here but think of bluebottles and leaf beetles - and exposing for dazzling highlights gives black shadows and can kill detail. The effect of strong sun on green vegetation is, if anything, even worse. The simplest solution is to shade the subject - a hand often works - but there's a risk the insect will move. The tiniest of air movement can cause leaves to shake but it's rarely continuous and sometimes I just wait for the lull. If that doesn't work then I just look for insects on the ground or on tree trunks.

I spent a little time in the garden re-familiarising myself with the method and found a few things to photograph. This fly was fairly co-operative, it sat still while I positioned the camera and shaded it. I'm not too disappointed with the result; it could be sharper but it is cropped quite a bit. The species looks like Scathophaga furcata (Say, 1832) based on the dark shaded cross-veins on each wing and the dark stripe on the front femur; although I'm not sure it's possible to be certain from this photo. My tentative identification was made using Stuart Ball's provisional key (Ball, 2007).

References:

Ball, Stuart G. 2007; Key to the British Scathophagidae (Diptera), Version 3.1