Thursday, 18 February 2010

Black-headed update II

Another snippet of news on the ringed Black-headed Gulls. The ringing details for the adult with the Latvian ring have been forwarded on by the BTO and the Latvian ringing scheme: he/she/it was ringed in Riga (the capital), on 7th March 2008, aged at the time as a bird more than 2 years old. It's back again this winter, so managed to survive a couple of 2,000km trips across Europe without too much hassle. Hope to see it again next winter!

Updated map:

It's interesting to add in the handful of ring readings gleaned over a winter in Vienna, some years back - which includes one bird from Malmo, the same site (and ringer?) as one of my Exeter ring-readings...:

Finally, a bit of an abstract from last weekend - bubbles in ice from a frozen hollow in a Dartmoor tor.

Tuesday, 2 February 2010

Friends at the weekend

I caught up with some old friends on Saturday. They probably don't recognise me, but that's fine. I don't really know them all that well either (though I'm learning more about them every time I see them!), but we've each been hanging round the Exe every winter since at least the early 1990s. They are, of course, Brent Geese - our standard Dark-bellied Brent (Branta bernicla bernicla). The Exe is actually designated as a Special Protection Area for its wintering bird population, in part for supporting an internationally important proportion of the world's Brent Goose population!

A small proportion of them bear coloured rings on their legs: I first consciously noted this back in the late 1990s or early 2000s and didn't think much of it, and to my shame, didn't follow them properly. Since then, weather, location and girlfriends permitting, I've tried to put in a few mornings each winter to look for marked geese on the river. Each of them has a single ring on each leg, which is usually marked with a letter, a number or a stripe or two - whilst some geese can wear neck-collars, Brent can't, as their neck markings are important social indicators: coloured collars would be likely to affect the behaviour and status of the bird carrying it.

I quickly discovered some constancy in their appearances: I've seen 'O-R2' - a bird with an orange ring with a single black band on the left, and a red ring with a white 2 on the right - most years since 2002, likewise ORR4. Interestingly, some of them seem to stick to particular parts of the estuary too: ORR4 and OYRH seem to prefer the Dawlish Warren and Starcross golf course area, whilst O-R2 and GFGX always seem to be at the northern end of the estuary, round Bowling Green Marsh and Powderham.

Typical 'scope view of the Brent at Starcross golf course - a bit gloomy, but nice clean conditions. Lovely short grass. This is the easiest place of all to see colour-marked Brent on the Exe...
Zoomed in a little, the old favourite ORR4 can just about be read, despite my grotty photo.

Eventually, I found out something about the origins of these birds. This was a bit of a mixed bag; slight disappointment as many of them were actually ringed on the Exe - so no mega-long-distance between ringing and resighting, but interest when I discovered that most were ringed as adult birds at a series of catches in 1996. This means that the older birds I see are now well in excess of 13 years old - that's no mean feat in itself... It's also just less than half of the current longevity record for a British-ringed Brent, which is a whopping 28 years, 2 months and 12 days between ringing and recovery!

A nice view, if not a nice photo, comparing an adult (centre, no pale fringes to the coverts - the back is a smooth charcoal grey) and bird of the year, with obvious pale fringes making a couple of whitish bars across the coverts. Notice also the lack of a neck collar on the young birds.

Saturday, at Powderham. Eye-candy in the middle, but no fewer than seven colour-ringed birds out of a flock of 250. The difficult thing is getting the numbers when they're faffing about behind the tussocks. A more challenging site...!

Over the years, I have also seen the odd bird which was ringed in Holland (like G1Y- and GRY9) and a couple that were ringed - excitingly - on their breeding grounds, in western Russia (like yellow JX and OKRD) - some 4,500km away from the Exe. So the birds which have survived so long, wintering on the Exe, are flying a corridor 4,500km long, twice every year. As well as all that incidental travel within their home and winter territories. I know it's not the same league as Arctic Tern and Manx Shearwater, but it's pretty good stuff nonetheless.

It's also fun to see that 'my' birds are often seen at other sites during their migration: the Waddensee between Holland, Germany and Denmark is the main place, but they also occasionally drop in further east in England.

They'll be off to Russia again soon. Hopefully they'll be back next winter!

In other news, a small group of us froze our butts off at Topsham Rec. on Saturday evening to do our annual gull count. Birds dropped in from an amazing height, presumably on the back of very clear skies and a tailwind, but numbers were not great. And boooooy was it cold work, standing around like that!