Saturday 30 March 2013

adult Thayer's Gull photoshoot

It is now or never on this one, as later today I head off to Iceland hopefully to see Iceland and Glaucous Gulls in good numbers so I'll try and do the odd post from there if I get the time. Anyway, I was hoping to do a post from yesterday when I went to Thetford and saw the (sort of) Black-bellied Dipper and a couple of Otters in the river. But, to cut a long story short, the day was grey, there were loads of people and the whole scene just didn't fill me with much enthusiasm to spend much time there nor write much about. Seems like everyone else has enjoyed their time in Thetford, so fair play.

So let's get back to the job in hand - adult Thayer's Gulls. Like the other ages, and as you'll see below, they are structurally very variable and you have to watch out for American Herring x Glaucous-winged Gull hybrids too. However, what seems to hold true is that on all birds P10 is pale tipped with an indistinct dark subterminal band, with the black on the outer web extending to the primary coverts, a mirror on P9 with black running through the leading edge (this mirror seems more extensive in the field on more individuals than literature suggest) with P6-P8 having pale-tipped tongues. P6 has a nice subterminal band, and on quite a few individuals P5 is unmarked (though on some there is a smudge of dark on the outer web of this feather). Once again, all the photos here are taken 16-23 February 2013 in northern California.
notice the short-legged appearance, dark eye and tepid bill colour. Structurally, too, this bird is quite squat and would be labelled in the 'classic' bracket of this species.

A more snouty individual with a pale eye - see the two images below for the same bird. Note the bright pink, relatively short legs and relatively dark grey mantle.

Purplish-pink orbital ring, tepid bill and even though the eye appears pale there is still some speckling present.

Thayer's Gulls have a very pale looking underwing, with dark markings restricted to the tips of the outer primaries. The leading edge of P10 shows a darkish tongue.

A typical individual, looking quite Iceland Gull-like in its facial expression - though note the dark iris

Same individual as above and below, illustrating a relatively well-proportioned looking gull

Just like a pale iris isn't always wholly pale, good views of a gull with a dark iris from a distance show paleness on closer inspection. Note the peppering in the iris of this bird; its orbital ring is pretty indistinct but it is purplish pink.

Quite a nice pose here, illustrating the upper and under primaries on a pretty classic looking bird - though many birds showed a more extensive mirror in P9 than I was expecting. This bird was no exception - the white mirror protudes well onto the outer web though is still bordered by black on the leading edge. Also note how on P9 and P10 the black tongue goes up as far as the primary coverts.

Another photo of the bird above.

A pretty classic looking, presumably female Thayer's Gull. This is the image of the species I grew up with, but there is far more variability in this species which presumably means that in a WP context, not all vagrants are being picked up.

A paler-eyed, longer billed individual to the bird depicted above. Again, note the distinctive nape hue and darkish grey mantle

A heavy-billed individual with a pale eye, though this is still peppered by dark spots. The rich pink legs and short tibia are typical of Thayer's Gull.
And finally for this post, watch out for imposters such as this bird - presumably an American Herring x Glaucous-winged Gull. They're pretty common in California, so must be pretty common in the Arctic regions where they interbreed. So, although unrecorded as a vagrant to Europe, they shouldn't be discounted: -

Glaucous-winged x American Herring Gull - note the rather dopey look and smudging akin to Glaucous-winged Gull and the paler mantle compared to Thayer's Gull.
same bird as above - very Thayer's-like primaries (though a large P10 mirror is almost tipped and note the extensive dark on the undersides of P7-10).

Sunday 24 March 2013

3rd-winter and near-adult Thayer's Gull photoshoot

It's been a while since I had the time to delve into the copious amount of images of gulls from California. And while still thawing out from today's trip to Crossness (where I had an adult Little Gull and a pair of Common Scoters), here are some more images of Thayer's Gulls of ages that you don't see too many photos of. In fact, in the week long trip I only managed to photograph the one 3rd-winter bird and a couple of near adults (presumably fourth-winters).

3rd-winter Thayer's Gull
This bird was photographed at Half Moon Bay, California during the late afternoon of 22nd February 2013. Though there is a fair bit of variation in this age, this bird is what you'd deem a 'classic' - the dark, speckled iris on this bird (some birds of this age can have pale irises, just like some adults), blackish subterminal bill band and adult-type primaries.
Note the well proportioned look to this bird, typical of what would be deemed a 'classic' Thayer's Gull. Deep pink, relatively short legs and mid grey mantle (slightly darker than Herring Gull)

primary-coverts still showing signs of immaturity, with black on P5-P10 and mirrors on P9 and P10

note the pale underside to the primaries, with just P10 showing an obviously dark tongue bleeding down on the leading edge from a large white mirror, and P6-P9 all pale tipped subterminally marked by small dark bands

Near-adult Thayer's Gull
Like the age detailed above, there were very few - just a couple - of near-adult Thayer's Gulls seen all week. This bird was on the beach at Jenner on 17th February 2013. A relatively large, snouty individual it was pretty much like an adult except for the dark on the gonys.

Essentially an adult plumage wise, with a dark gonys suggesting immaturity, tepid bill colouration and perhaps the streaking on the lower nape more extensive than on an adult. Note the 'almost black' primaries extensively pale-tipped and mid grey mantle colour

Showing a fairly classic adult-type primary pattern - extensive white mirror on P10, the mirror on P9 extensive yet restricted to the inner web, P6-8 showing nice grey bayonets and just a slight dark smudge on P5. Although crinkled on this photo, also note the lack of significant black/darkness on the underside of the primaries

Saturday 23 March 2013

The first signs of Spring in the snow

I looked outside when I woke up this morning, to be greeted by the usual grey clouds, so typical of this winter, along with a deluge of snow falling. Being London, with all the heat and that, it wasn't sticking so I ventured out locally. The Rotherhithe gulls feasted on my bread, but alas it was just the usual suspects and so I headed on to Crossness.

Walking east along the Thames path, all I seemed to be getting was a face full of snow. Upwards of a thousand Black-headed Gulls, the odd Oystercatcher and Curlew and a couple of Black-tailed Godwits, but that was it. Hundreds of Teal and Gadwall were squabbling away at the incinerator outfall as I headed towards the paddocks, where I was greeted by this sorry looking chap: -

1st-summer male Northern Wheatear, Crossness 23rd March 2013
I did feel a little sorry for this Wheatear as on its first journey north, having done the Sahara and the rest of Europe, it was only to be greeted by the near zero temperatures here in London. However, on the plus side, they're hardy little things given where they tend to breed and the ground wasn't frozen, so it seemed content on pulling up innumerable earthworms to keep itself going.
adult Mediterranean Gull, Crossness 23rd March 2013

Walking back along the Thames with Mike, I heard the familiar call of a Mediterranean Gull over the river and it was only a matter of seconds before a couple (presumably a pair) did a neat fly by before heading off downriver. After that, with optics and clothes sodden, enough was enough and it was back to the warmth of home for the evening.

Monday 18 March 2013

Blinged gulls from the weekend

One thing is for sure, gull ringing coordinators aren't half efficient in getting back to you when it comes to ring reporting. From the 10 ringed gulls I read on Saturday, I've had all 10 back already, including one from Belgium and one from Norway. In fact, it's a real blessing when you get a Norwegian ringed bird as you get the results immediately submitting it through Ringmerking - a phenomenal, user friendly database. So here is a nice, docile looking 1st-winter Great Black-backed Gull: -
JP783 - ringed as a chick on 7th July 2012 at Store Vengelsholmen, Mandal, Vest-Agder, Norway (844 km away as the gull flies)
This 3rd-winter Herring Gull was Belgian ringed, and from a scheme I've come across on a couple of occasions previously. This bird is a regular at the tip: -
PH.AS - ringed as a chick at Zeebrugge, Belgium on 8th July 2010, turning up at the tip on 17th December 2010 and 22nd January 2011. It then headed back across The Channel and was seen at the massive landfill site at Blaringhem, Nord, France on 13th October 2011 before arriving back at the tip here on 24th December 2011. It again went back to Belgium on 15th April 2012 before favouring Blaringhem landfill on 26th April 2012, 4th and 19th October 2012. Then came this sighting. Gulls are certainly creatures of habit.
This adult Lesser Black-backed Gull, although ringed by the NTGG on the tip, it had ventured as far south as Madrid: -
KB9T - ringed on the tip on 24th March 2012, it was still here on 21st July 2012; by the 16th September 2012 it was at Colmenar Viejo landfill, Madrid, Spain. Saturday's sighting is the first since then.
Once again, reading gull rings is becoming a decent part of my birding, especially this winter with the general level of birding having been so poor here in the London area. Perhaps there'll be some sign of Spring come next weekend, but that seems hopeful judging from the current forecast.

Sunday 17 March 2013

Glaucous, Caspian and other tip gulls

With it getting nowhere near spring, and those days of migration seeming a long way off still, yesterday I headed back to the tip to see what was about. Presumably the cold weather had pushed gulls from the continent, and it was obvious there were many more gulls than last weekend. It didn't take more than 10 minutes to pull out this juvenile Glaucous Gull - a nice biscuit coloured bird, which seems to be the case for a lot of the east coast birds we get (they seem rather more pallid in Ireland).
Then it was onto Caspian Gulls, with three stunning 1st-winters present. It has been over a month since I've seen anything but this age, so perhaps at least the adults have already departed eastwards towards their breeding colonies.
Bird 1

Bird 2

Bird 3

Bird 3
Four Yellow-legged Gulls included this 1st-winter, and although ringed isn't that interesting - it was ringed at the same site exactly a month ago!
1st-winter Yellow-legged Gull (ringed YY1T)
There were also quite a few ringed birds, many from the NTGG (with the most interesting being an adult Lesser Black-backed Gull that had been to Spain and back) as well as a Belgian Herring Gull and a Norwegian Great Black-backed Gull. Half a dozen Mediterranean Gulls were getting a bit frisky too.

Friday 15 March 2013

2nd-winter Thayer's Gull photoshoot

If somebody was to try and describe what a typical 2nd-winter Thayer's Gull looked like, I'd say good luck to them. Mind you, guess the same could be said about describing the same age of Herring Gull. As always, Chris Gibbins has done as good a job as anyone will and recently wrote this about the birds he saw, also in California, in December 2012. Many of his birds taken at the same sites as in the photos below - all taken in the period 16-23 February 2013! You'll notice that the Californian sun has got to a lot of birds between December and February, but structurally they remain the same - without doubt an 'in between' gull, where one moment you get an Iceland (Kumlien's) Gull-like feel and then the next it turns into an altogether more Herring Gull-like bird.

Photos 1 to 3. 2nd-winter Thayer's Gull, Milpitas, California Feb 2013 an average bird structurally, though quite retarded moult wise. No mirror to P10 with the outer primaries obviously dark due to the dark pigmentation from the outer webs bleeding onto the inner webs, and the often quoted 'venetian blind' effect created by the paler inner primaries (though in this bird the secondaries are bleached)
It is a case of educated guesswork based on experience, gut feel along with a number of plumage characters that when pieced together get you to a second-winter Thayer's Gull. However, with just a week to play with, it was a steep learning curve so hopefully this load of shots will be useful. Certainly compiling and writing about them has been useful to me so please do enjoy and do comment.
Photo 4. 2nd-winter Thayer's Gull, Jenner, California Feb 2013 a long-winged bird showing the neatly fringed brown primaries, 'fat feathering' that sometimes this species seems to show on its throat and solidly brown based tertials

Photos 5 and 6. 2nd-winter Thayer's Gull, Jenner, California Feb 2013. Quite a pale eyed bird which interestingly shows a white mirror on P10 but the primaries are otherwise characterised by the typical thayeri pattern - dark extending onto the inner as well as outer webs of the four outermost primaries as well as bleeding up to the primary coverts. Would this bird be pushed as a thayeri in a vagrancy context over here? I do wonder

Photos 7 and 8. 2nd-winter Thayer's Gull, Salmon Creek, California Feb 2013. Quite an advanced, Herring-like bird with a mirror to P10. However, the primary pattern is fine for thayeri and the very dark brown tail band is within range, though the uppertail coverts are perhaps cleaner than average. Not sure how identifiable this bird would be in Europe though...
Photo 9. 2nd-winter Thayer's Gull, Petaluma, California Feb 2013. Perhaps a fairly typical bird, with chocolate primaries fringed pale, obviously dark tertials and note the rather squat appearance caused by quite deep pink legs
Photo 10. 2nd-winter Thayer's Gull, Petaluma, California Feb 2013. A fairly chunky looking bird, yet fairly small in the field with a slim, Iceland-like bill. Note the pale edged chocolate brown primaries and solid brown tail with brownish uppertail coverts
Photo 11. 2nd-winter Thayer's Gull, Milpitas, California Feb 2013. A fairly uniform bird, especially tail and secondary wise though the outer primaries show what you'd expect for a thayeri and there's a venetian blind effect there too. At times, I still get a slight Glaucous-winged Gull feel on this bird but this stout appearance isn't necessarily a negative for thayeri
Photo 12. 2nd-winter Thayer's Gulls, Milpitas, California Feb 2013. Two contrasting birds in terms of moult, as well as the bird in the foreground appearing more snouty. Both are typically long-winged with dark brown primaries
Photo 13. 2nd-winter Thayer's Gull, Golden Gate Park, California Feb 2013. Close inspection shows a pale eye on this bird. Otherwise fairly typical with a mantle shade coming through that is a tad darker than American Herring Gull

Monday 11 March 2013

juvenile Thayer's Gull photoshoot

I've finally managed to sort through, and near enough categorise, all the 1000s of gull images that I took in California. As one of the main targets of the trip was to have a look at Thayer's Gulls, I'll start with this species. Here are a load of juveniles - all taken in the period 16th to 23rd February 2013. Hope this will be useful viewing either now, or when the next candidate turns up in Britain or Ireland. Structurally they were very variable, ranging from snouty to rather meagre, Iceland Gull-like birds. One thing I have learnt is the variability of the species, and note in the following images the plumage wear and variable scapular moult (which is apparent in some of these birds, countering the popular late 90s/early noughties belief of Thayer's not showing this in midwinter).