Monday, April 29, 2013

Identification of Blyth's Reed Warbler

Over the past few years I have seen three Blyth's Reed Warblers in Britain and the last one, on Fair Isle in 2011, was mist netted and ringed and so I was able to get some in-hand shots of the bird. The photos have been sitting on my hard drive serving very little purpose since then. I thought I'd stick a few on my blog so that they are available for anyone wanting help with identifying putative Blyth's Reed Warblers or who just want to brush up their ID skills.
Blyth's Reed is an un-streaked Acrocephalus and as such is pretty difficult to identify as there are a number of other, very similar, un-streaked Acrocephalus warblers in the Palearctic region. Blyth's, Marsh and Eurasian Reed can all be told apart on song but the chances are a bird in the UK will be a first-winter bird in the autumn and will be silent. If it does call you are listening for a Lesser Whitethroat type 'tuk'  which is unlike the 'tcharrr' of a Eurasian Reed or the softer note of a Marsh warbler. So what do you look for in a Blyth's? They have a combination of relatively short primary projection and clear emargination on two of the primaries. O.K. if you have a bird in the hand but difficult in the field! The emargination on the primaries can be seen on the first photograph but it would not, I suggest, be of much use generally.

1st autumn Blyth's Reed Warbler Acrocephalus dumetorum  Fair Isle October 2011
In this second picture we can see that the wing is quite rounded, more so than in Marsh Warbler or Eurasian Reed Warbler. The bird has a short primary projection, about 50-60% of the length of the exposed tertials. According to Kennerley and Pearson in " Reed and Bush Warblers" Helm 2010, "The wing point is formed by p3 and p4, and p5 is often so close in length that just six closely spaced primary tips are visible on the closed wing, fewer than in Marsh and Eurasian Reed." This feature is clear on this bird and it is a particularly important identification feature

1st autumn Blyth's Reed Warbler Acrocephalus dumetorum  Fair Isle October 2011
In this third picture we can see that the bill is quite deep and broad based and so it appears to be more substantial than on Eurasian Reed Warbler but they tend to be about the same length. The bill of Marsh Warbler is slightly smaller. Guidebooks always point to the long, sloping forehead and the low angular crown, peaking just after the eye as a useful ID feature of Blyth's and again this feature can clearly be seen in these photographs. This bird has a clear open-faced expression that can also be a useful ID feature of Blyth's.

1st autumn Blyth's Reed Warbler Acrocephalus dumetorum  Fair Isle October 2011

Blyth's Reed lacks the hint of warm tawny-brown shading to the rump and uppertail coverts that you would expect on a Eurasian Reed Warbler and it is not as greenish as a Marsh Warbler's rump. The overall colour impression of this first-autumn bird is a cool olive-brown above with hints of warmer, browner tones in the wings and on the tail and pale below with a whiter chin and throat. On these pictures we can see that the supercillium is quite indistinct, especially behind the eye. It is quite poorly defined on this individual. Blyth's tend to have a supercillium that bulges in front of the eye but that is less prominent behind the eye and this gives the bird a bland appearance.

1st autumn Blyth's Reed Warbler Acrocephalus dumetorum  Fair Isle October 2011

This bird is showing very worn rectrices and fresh primaries. It is a classic first-winter bird in autumn: the tail feathers are browner than in an adult and the upperwing coverts, tertials and flight feathers are all brighter than in an adult. The first three photographs show that the upper mandible is grey with pinkish cutting edges whilst the lower mandible is a pale pink.

There are a number of confusion species. As well as Marsh and Eurasian Reed, Large-billed Reed Warbler Acrocephalus orinus is probably the most difficult to tell apart - fortunately not a problem in Britain...not yet!

Back on Fair Isle during the week of September 18th to 25th I witnessed a repeat performance as another Blyth's Reed was located, captured and ringed. This bird then hung around showing well on and off in a couple of crofters' gardens for the rest of the week. I took photos of the bird in the hand.

The next three photographs are of the 2015 bird.The gingery colouration on the primaries and secondaries is quite noticeable on this bird. Note the pale pink lower mandible. The wing length of this bird was 60.5 mm. I think that the wing length for Eurasian Reed Warbler lies between 65 and 70mm so the wing length of this bird is quite short in comparison.

Tuesday, April 23, 2013 bins!

I've seen a good number of Ring-billed Gulls Larus delawarensis in North America but I've only ever managed to see a handful in the UK. Two reasons for this: firstly Ring-billed Gulls are pretty scarce; secondly I'm not much of a gull-watcher. Miserable evenings in the cold, wet, half-light sifting through half a billion Herring Gulls on a midlands reservoir is my notion of Hades. Likewise hanging around stinking land-fill sites trawling through a swirling mix of Black-headed Gulls, Lesser Black-backed Gulls and yet more Herring Gulls in upwards of twenty seven plumage variations leaves me a touch unfazed. So when I heard that a first summer Ring-billed Gull was showing well just twenty minutes from my house I decided to give this one a go.
When I arrived at Melton Mowbray Country Park the weather was just right - sunny, dry, warm and fairly still. I should get great views of this I thought. On opening the boot of the car I realised that I had not brought my bins. Stupid...stupid! A cardinal error. Fortunately my scope was in the car and I had a 400mm lens on my camera so I was not wholly without optics. If the bird is on the water I should be OK as I can scan with the scope. If it's flying about I've got no chance.

1st Summer Ring-billed Gull Larus delawarensis Melton Mowbray
I set up my scope at the edge of the lake and scanned the few gulls loafing in the middle...Common Gull...Common...Common...Common....Common etc. All bloody Common Gulls. It's at this point that you realise how easy it is to string a bird. The temptation to turn an obvious Common Gull into a stringy Ring-billed was pressing. Bit more of a scan...Common...Common...Black-headed.
1st Summer Ring-billed Gull Larus delawarensis Melton Mowbray
Then bingo! A big, heavy Common Gull with a massive parallel sided pink bill with a black tip. Ring-billed. It was an aggressive individual; twice attacking passing Common Gulls. It stayed some distance away and I could only take a few record shots of it sat on the water. Ten minutes later it took flight along with the Common Gulls and I had to follow it through the camera lens as I had no chance of staying focused through the scope.

1st Summer Ring-billed Gull Larus delawarensis Melton Mowbray
I did manage to capture a few images as it was easy to keep on the right bird due to its mangled tail. In flight the bird looked bulkier and longer winged than the accompanying Common Gulls. In particular its head and bill were much stockier.
1st Summer Ring-billed Gull Larus delawarensis Melton Mowbray
 The pale wing panel on the secondaries was quite an obvious feature although it can't be seen on any of these pretty useless photographs! I couldn't pick out any dark crescents amongst the scapulars or any narrow pale tips to the tertials - as all of the guide books say you should. It is a birding education though looking at the differences between Common and Ring-billed Gulls. Side by side the differences are obvious but I doubt if they would be so with a lone bird.
1st Summer Ring-billed Gull Larus delawarensis Melton Mowbray

1st Summer Ring-billed Gull Larus delawarensis Melton Mowbray
 I'll probably have another bash at this bird tomorrow and try for some more worthwhile pictures and this time I'll take my bins!

Friday, April 19, 2013

Eight crows a day.

We spent last week on Anglesey in North Wales looking for migrants as well as getting in some much needed walking. We had some good numbers of common migrants with Swallows arriving in numbers on Monday 15th April - well over 100 during the morning around Breakwater Country Park - along with a few House Martins and Sand Martins. The 16th saw a fall of Willow Warblers with over twenty counted along with over thirty Chiffchaff. Sandwich Terns appear to be quite plentiful with over 40 at Cemlyn Bay on 18th April. There were four adult Mediterranean Gulls there too as well as a single Arctic Tern. We picked up a Common Tern at Newborough. On the 18th we were at South Stack where there was an impressive arrival of Northern Wheatears - birds were bouncing around on the heather in all directions. We estimated in excess of fifty birds.
But for me the week will be remembered mostly for the first time that I had seen eight species of crow/corvids in a single day - although I didn't manage to photograph them all.

On Sunday 14th we were walking around the lake at Rhosneigr when I caught sight of a Hooded Crow Corvus cornix battling against the gales that were blasting in from offshore. It was in the company of a couple of  equally knackered Carrion Crows and they soon struggled to ground near the northern shore of the lake. Hooded Crow - first for Wales.
Carrion Crow Corvus corone
We had already seen plenty of Rooks at the southern end of Anglesey as we drove north along the A55 and Jackdaws were just about everywhere. Four species of 'crow' and because I was on Anglesey; one of the best places for Chough and Raven I figured that if I could catch-up with a Jay I'd manage all eight.

Jackdaw Corvus monedula

Raven Corvus corax - a friendly pair
Over to South Stack RSPB reserve on Holyhead Island - a guaranteed Chough site. Easy pickings! A couple of Chough flying by as soon as we got out of the car and Ravens flying over and calling. A volunteer warden in the RSPB visitor's centre told us later that there have been counts of up to 1 600 Ravens roosting in the Pine forests near Newborough!
Rook Corvus frugilegus
Magpies were seen, normally in pairs, throughout the day and those on South Stack were getting blown every which way. Just a Jay needed now!

Magpie Pica pica with the wind up its jacksie
We drove down to The Dingle near Llangefni - a picturesque, sheltered, wooded, welsh valley if ever there was one and as Bob's yer uncle a single Jay flew through the woods. I've not managed to get pictures of Jays as I find them pretty shy and skittish although noisy. Later this year we plan to bird western Scotland so I might get some shots of Hooded Crow but Jays might have to wait. Six species photographed so far and two to go - three if we count Nutcracker but I haven't seen one of those in the U.K. since the Staffordshire bird in 1991!
(Red-billed) Chough Pyrrhocorax pyrrhocorax


Friday, April 12, 2013

A Tale of Two Grebes

On Wednesday I drove down to Thetford Forest to spend some time looking for Golden Pheasants. I had planned to spend the last few hours of daylight on Wednesday and the first couple of hours on Thursday hoping to get some photographs of this elusive and fast-disappearing species. On the way down I passed Fen Drayton RSPB reserve in Cambridgeshire and as I knew that there had been reports of both Black-necked and Slavonian Grebes I figured it was worth a diversion. I had a walk around Ferry Lagoon looking for migrants first of all but there was nothing bar four Chiffchaff and a lone Blackcap but at the southern end of the lagoon I managed to locate the Black-necked Grebe feeding a fair way out. However, it soon started to move nearer to the bank where I had set up my gear and pretty soon it was close enough to take photographs. I had been watching the bird through the camera lens and so had a narrow field of view. Taking my eye away from the lens so that I could have a quick look through my bins I was surprised to see two birds more-or-less together. The second was the Slavonian Grebe and this had appeared from nowhere. Both birds were in summer plumage; the Black-necked complete and the Slavonian almost so this was a great opportunity to compare these two scarce grebes side-by-side. I had never seen these together in summer plumage before. I have seen them together in the winter on a number of occasions.
Slavonian Grebe Podiceps auritus - Fen Drayton
The first thing that struck me was that the Black-necked Grebe looked slightly larger than the Slavonian but this could have been the result of it sitting higher in the water compounded by its steep forehead and peaked crown as both of these birds overlap in size - the Slav often being the larger. Both birds were sporting golden-yellow ear tufts - the tuft on the Slavonian was a little more ragged. Both birds had amazing red eyes. Note the bill in the photograph of the Slav below - straight, quite small and tipped pale yellowish/horn. The bill of a Black-necked Grebe is all black, up-tilted and sharply pointed. This bill difference is a good feature for separating the two species.
Slavonian Grebe Podiceps auritus - Fen Drayton
Because the Slavonian Grebe was not yet fully moulted it looked a bit untidy. If you compare these photographs you will see what I mean. There were still some winter plumage white feathers on the chin and upper throat as well as the upper breast but it was clear that the front and sides of the neck were turning reddish - a key difference between the two species as the neck of the Black-necked Grebe is all black - hence its name! The flanks too still had signs of winter plumage and were not yet entirely deep red.
Slavonian Grebe Podiceps auritus - Fen Drayton
The rear of the two birds was different with the Black-necked showing a fluffy, almost Little Grebe, back end whilst the Slavonian had a more stream-lined lower in the water end which was white.
You can see this feature in the picture below, although the Slav is out of focus due to a narrow depth of field. You can also tell the difference in head shape. The Black-necked has a steep forehead with the crown peaking directly over the eye, whereas the Slav's crown is flatter and has a definite peak behind the eye. The Slavonian has a longer sleeker body and looks a bit like a small Great Crested Grebe whereas the Black-necked recalls a big Little Grebe - if you know what I mean!
Black-necked Grebe and Slavonian Grebe Podiceps nigricollis and P. auritus - Fen Drayton
The Slavonian Grebe followed the Black-necked Grebe all of the time that I was watching. They behaved as if they were a pair with the Black-necked leading. Also the Black-necked called a number of times as it approached the bank but I don't think I heard the Slavonian Grebe at all. Both birds were happily feeding and appeared to be settled, they have both been present for some time.
Adult summer Black-necked Grebe Podiceps nigricollis - Fen Drayton
No doubt as the Slav progresses with its moult it will become more spectacular but it will have a way to go before it can beat the beauty of the Black-necked Grebe seen in the following two shots.
Adult summer Black-necked Grebe Podiceps nigricollis - Fen Drayton
In this portrait shot of Black-necked Grebe the tiny all-black up-tilted and sharp-pointed bill along with the incredibly steep forehead peaking above the eye are obvious. Both of these features tell you that you have a Black-necked Grebe and not a Slavonian.
Adult summer Black-necked Grebe Podiceps nigricollis -Fen Drayton


Monday, April 8, 2013

A bit of a twitch!

Earlier this year I drove over to Beeley Moor in Derbyshire to look for a Great Grey Shrike Lanius excubitor that had been frequenting an old quarry for a couple of weeks. Needless to say I didn't locate the bird even though we put in a couple of hours searching. It was still there yesterday so this morning I fancied having another go even though it promised to be bitterly cold up on't' moors with an easterly wind howling in from Moscow. I expected a similar search and seek mission to the last visit and I was resigned to getting frozen and possibly not seeing the bird. As we approached the site my wife and I had the following conversation. "Are you going to park just here on the right?" "Yes, this is where I parked last time." "Good...'cus there's the Shrike by the gate." "!?!!*" Birding's like that! Ten minutes later it had flown off and despite searching could not be relocated. It might never have been there.

Great Grey Shrike Lanius excubitor Beeley Moor, Derbyshire
Whilst searching for the Shrike an Osprey flew directly overhead heading north. This was a bonus bird but hardly a surprise when you take into account all of the reservoirs that can be found in this area - along with the time of year.

Osprey Pandion haliaetus
That the idea of reservoirs popped into mind due to the Osprey then had us heading a little further south to try for one of the four reported Great Northern Divers at Carsington Water. Here we heard and saw our first Chiffchaffs of the year - 4 in total in a thirty minute spell. Hardly a record but nice to hear after all of the cold, snow, wind and stuff of the last few months. The divers were proving to be particularly difficult to locate but a couple of Redshank in full breeding kit were pretty obliging.
Redshank Tringa tetanus Carsington Water Derbyshire
 We eventually located just a single Great Northern Diver some distance away on the far edge of the reservoir. It was too far away to photograph and it was not that convincing a bird. Had I not known that it was probably one of the four that has been reported on and off for a month or two I would have seriously considered this one to be Black-throated. This picture is of a bird I photographed earlier.
Juvenile Great Northern Diver Gavia immer
Not a day to be remembered for migrants piling into the area but Great Grey Shrike, Osprey and Great Northern Diver just an hour away made it a bit of a twitch worth doing.