Tuesday, July 31, 2012

Scotland

I spent last week in Scotland with Alex Jones, Chris Bridge, and a handful of other ringers from Merseyside and Shropshire. Right up on the north coast of Scotland, in fact, on a small island called Eilean Nan Ron. The main aim was to ring these critters:

British Storm-petrels. We caught 1,300 in total, 120 of which were retraps including one with a Norwegian ring and one with a Portuguese ring. That sounds exciting; in reality, it's not really... but that's a story for another time.

I spent most of my time checking out the petrel wings, particularly the moult of the secondaries.

Storm-petrels appear to be big birds stuck in small bird's bodies with at least two moult centres in the secondaries and often some retained feathers. But more on that at a later date.

One other interesting thing that I noticed on several birds: filoplumes. These are modified feathers that act a bit like cat's whiskers. They show up as thin silvery strands on the bird's breast side and presumably help the bird find its way through its burrow at night.

We also managed to catch and ring a few of these on the island:
Great Skuas. They varied from cute (like the bird above) through various stages of attractiveness...
...culminating in the downright brutish adults.

Adult birds are huge beasts, solid blocks of angry muscle, as modelled by Chris.

The bird's bill is every bit as lethal as you might imagine; but so are its claws.

In contrast to the petrels, Great Skuas are little moulting birds stuck in a big bird's body. Juveniles undergo a complete moult in their first winter — so, can we age this bird? Great Skuas are reported to start breeding at five or six, occasionally four, years old so circumstantially this bird should be at the very least four years old. Not that circumstantial evidence counts for anything, you understand. The moult of juvenile birds starts a lot later than adults and consequently finishes a lot later — thus the fact this bird shows no active moult is strongly indicative that the bird is not a second year (though note some adults may have just started their primary moult; a 2cy would just be finishing it).

This bird shows scattered white feathers on the wing and the head; this seems to be a common feature in Great Skuas (see e.g. this bird and this bird) — I wonder if the amount of white (leucism?) increases with age or if it's just related to individual variation. Note also that the secondaries appear blacker than e.g. the primaries and the greater coverts, creating something of a 'pseudo moult limit' — they have not been moulted during this autumn's moult cycle (yet to start at all in this bird), though they are likely a fair bit newer than the inner primaries. The secondaries are moulted much later in the moult sequence than the primaries, which means they might be up to a couple of months newer. Additionally, they're generally rather protected compared to the primaries and, perhaps most significantly when it comes to their contrast with the rest of the wing, I suspect they're generally just blacker to begin with than the rest of the feathers.

Almost as big but considerably less dangerous, Chris and I managed to grab a Great Black-backed Gull each.

We took a boat tour around the island — always nice to see things from a different perspectiv.


I thought this was a lovely photo until someone pointed out that the arch is shaped like a penis.

This is the area known as the slabs; it holds a colony of breeding petrels and is one of the areas where I spent two nights ringing. For an idea of the scale, keep an eye on the arrowed rock...

Here's that arrowed rock again. NB the perfectly normal-sized people stood in the right of the photo. 

Black Guillemots (in contrast to Fulmars, which were virtually absent from many of the cliffs) seemed to be extremely numerous this year and many were carrying fish back to their nests.

Despite the fact it's completely out of focus, I really like this shot.

Two 2cy birds were loafing offshore:

The ringing wasn't just restricted to sea-birds. Alex found this juvenile Common Snipe. It looks like it's been stippled with silver paint.

There were several Northern Wheatear families on the island. We caught two juveniles:

And one 2cy male undergoing its complete post-breeding moult.

Off the island, we swapped our ringing pliers for scopes and headed off to do some birding. Even around the harbour there are plenty of interesting birds to see: Twite, Rock Dove, dodgy Common Redpolls, breeding Black-throated Diver etc.

From the north coast we headed down to the Speyside area. An Osprey was fishing along the River Findhorn and a pair of Slavonian Grebe were on Loch Ruthven.

Next morning we took a dawn wander around Abernethy. Our (per Chris) "guaranteed" Capercaillies failed to materialise — it seems, chatting with the reserve wardens, that it's actually been a really bad year for the species — but we did have several flyover crossbills of assorted flavours (more about those another time... possibly). After a power-nap back in the hotel, we headed to Cairngorm. The walk to the summit was pleasant if not a little tiring.

We thought we might have beaten the system when I found a family of grouse about half way up — they turned out to be Red Grouse; we had to keep walking to the top before we connected with Ptarmigan. A group of seven (a male, two females and four first-years) were feeding by the side of the track to the summit.


Back down at the café, a pair of Snow Buntings (both 2cy birds by the looks of things) were pottering about.

Then the heavens opened and a bitterly cold wind started to blow. We chickened out of the walk down and headed into the café to catch the train back down. No trip to the top of Cairngorm would be complete without a trip to the gift shop; and what better way to remember your visit to the top of Cairngorm than with a pen made of corn?

Or if that doesn't tickle your fancy, how about a Guatemalan worry person? "From the Mayan people to you."

We resisted both and caught the train back down to base camp. And with our descent, it was all over; all that was left was the drive back to Liverpool.

Saturday, July 14, 2012

My (mostly) non-birding week

I've been in London for most of the last week and consequently haven't got a great deal of bird-related stuff to report — but that's not to say the last seven days haven't had interesting moments.
I should start by saying congratulations to my sister, Kate, who on Monday graduated with a Masters degree in Pharmacy.

And congratulations to Kate's boyfriend, Anthony, who — making sure he stays one step ahead of Kate — was awarded his postgraduate clinical diploma.

On Wednesday I went to the Butterfly Conservation Big Butterfly Count launch at London Zoo. And look who I bumped into:
It's an awful photos... but still, omg, it's Sir David Attenborough.

And here's the short video I made. You might want to turn the sound up; he's not the sort of guy who shouts.

Yesterday, back in the northwest, I met up with Alex Jones at Burton Mere Wetland — the first I've been to the site. It was nice, though there weren't many birds... A flock of Black-tailed Godwits, a load of Little Egrets, but precious little else.

This morning I joined David Norman and others to help out at the Oxmoor LNR ringing demo. It went well, not least thanks to two Kingfishers (the same two from last weekend, in fact); Kingfishers always go down well with the crowd!

And I guess I can't finish without mentioning this. I headed down to Pickerings Pasture this evening, my theory being that godwits are often on the estuary at low tide and that — given I've seen e.g. dodgy shelduck hybrids at Frodsham and later off Pickerings Pasture —they're likely (some of) the same godwits that roost on number 6 tank. The tide was in a bit higher than I'd anticipated and so only the far sandbanks were exposed; even so, the theory kinda worked... there were 16 islandica Black-tailed Godwits along the water's edge. No Hudsonian Godwits, though. Nor any 2cy female limosa for that matter. Oh, damn, I've gone and really put my neck on the line now.

Sunday, July 08, 2012

A few more warblers

The emphasis being on few. I was down at Woolston this morning where we caught about 25 birds. A few juvenile Blackcaps were nice to see. This 1cy male has yet to start post-juvenile moult; the black feathers in its crown were juvenile feathers.


We caught our first juvenile Reed Warbler of the year; it refused to cooperate for photos, so here's a rather pointless wing shot instead.
Those wings'll carry it to Africa.

No Sedge Warblers — we didn't even hear one — and only one Common Whitethroat, though it does at least seem that Wrens, Common Chiffchaffs and Bullfinches have had a reasonably productive breeding season.

Saturday, July 07, 2012

Testing out my new lens

Just before I left Falsterbo, my "in-hand" lens gave up the ghost. I've been a bit lost without it but had been umming and ahhing for some time over what to replace it with. In the end I went for a fairly standard 18–55mm f/3.5–5.6 kit lens, which arrived on Wedensday. It's nothing special, but I was keen to try it out.
I joined David Norman for some early morning mist-netting at Oxmoor LNR — the site should be dripping with breeding warblers and, after the recent dismal weather, we were expecting to catch large numbers as they took advantage of the dry spell — the reality couldn't have been further from the truth; in the first net round we caught just a single bird, a Robin.


The bird is in heavy moult, growing a chunk of inner primaries and having dropped all of the tail feathers almost all at once. This photo was taken before dawn, so it seems that my new lens copes well in low light.

Sunrise behind the Eddie Stobart warehouse...

Second net-round was equally dismal; again, just a single Robin, this time a juvenile undergoing post-juvenile moult.

Things eventually started to pick up on the third net-round. We caught some juvenile Sedge Warblers, the first juvenile Acrocephalus warblers of the year — a minor success in what seems to be a dismal year for the species.

We also caught two of these beauties:
This bird should be a male. Juveniles often seem to show some orange on the lower mandible; it's said that young males never show more than 1/3rd of the length of the bill orange (on adult males the lower mandible is usually completely black). This bird, to me, seems to show more than 1/3rd orange but the bird's plumage was very blue — a characteristic of males and a feature made all the more apparent when we held it next to the second individual, a bird that we sexed as female.

female left, male right — nicely illustrating the difference between blue-green and green-blue.

In actual fact, compared to the second individual, the orange on the bill of the first isn't *that* extensive. Here's the bird we sexed as a female to compare:

A male Bullfinch added yet more colour to the ringing

It's a second-year that's retained two juvenile greater coverts; and, of course, the obvious biscuity-tipped carpal covert.

This 2cy male Common Whitethroat had moulted its outer six primaries and inner four secondaries some time over the winter.

The moult limit was extremely subtle — you can probably see in the photo above that the inner four primaries are older than the outer ones; the old secondary is harder to detect. Given the relatively high degree of wear to the newer pre-breeding (winter-moulted) feathers, it's tempting to think that they might have been moulted relatively early on in the winter.

Back to Sedge Warblers, adults this time. We caught several female warblers with active brood-patches indicating that they were or had just finished incubating eggs; one of these birds had been recorded as being at the same stage when she was first ringed but, with not enough time between then and now to have completed rearing a first brood, it seems that she is trying again following failure the first time around. It was interesting to note the difference in wear between individuals. This individuals is rather fresh looking:


While this individual is considerably more worn:


Sedge Warblers are reported to follow two or three moult strategies. Some birds moult as soon as they arrive in Africa, then have a partial pre-breeding moult before spring migration — presumably that's what we're seeing with the second bird; the worn primaries suggest an early-winter moult while the apparently fresher-looking feathers on the mantle may the the product of a pre-breeding moult, though the worn tertials suggest that any pre-breeding moult was limited to the body. Other birds wait until they have reached their southern African wintering grounds before moulting; these birds do not have a pre-breeding moult — with fresh primaries, tertials and body feathers, that is presumably the moult strategy the first bird has followed. There is an intermediate strategy with some birds starting moult on arrival in Africa before suspending and completing once they arrive on southern African wintering grounds. A topic I've never really looked into much before and interesting to think that two birds from the same site could potentially have undergone such different wintering strategies. I wonder why? Definitely something to take a closer look at next time I handle some more Sedge Warblers!

This Reed Warbler was a known-age retrap, originally ringed several years ago:
 


Finally, this male Goldfinch was also a retrap. It had moulted all of the greater coverts and the central two pairs of tail feathers during its post-juvenile moult.



So, all-in-all I'm pretty pleased with my new lens. It's smaller and a lot lighter than my previous lens but still seems to do an equally good job, and the size and weight should make it a lot easier for transporting around — especially when I'm trying to stuff my life into a backpack ready to take the next EasyJet flight!