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.

2 comments:

Jack Ashton-Booth said...

Hi Ste

Keep up the great posts mate, loving the moult work!

Best Wishes

Jack

Stephen Menzie said...

Thanks Jack, really glad to hear you're enjoying it :)