Wednesday, 4 February 2015

Tracked from the Arctic

Third-winter Iceland Gull (right, with adult Black-headed Gull). This bird, hatched in Greenland, was ringed in Norway and has also been seen in Denmark before visiting London last month.
Somewhere in remote southern Greenland, high on a steep and windswept cliff, an egg hatches. Breaking free from its ovid pod, a sticky, downy and unsteady chick takes its first steps before its mother gently cleans, preens and broods it. This ball of downy fluff is the latest arrival in a colony of Iceland Gulls – a species which breeds here and nowhere else on Earth.

The year is 2012, and our chick arrives in the few weeks of warmer weather that pass for summer in the Arctic. Not all chicks make it to fledging, but this is one of the lucky ones, and come autumn the youngster moves away from its natal area and, eventually, to northern Europe. We know this for a fact because the following spring, on 12 April, ringers catch the bird in Oslo, Norway, and mark it with a black ring coded ‘JK0P’ in white (also with metal ring number 4261758) – one of only 18 Iceland Gulls to be banded in the country.

JK0P lingers in Oslo until 24 April, after which there are no more sightings until the autumn. Then the bird is sighted again on 6 November, but this time in Denmark, 510 km SSW at BlÄvandshuk on the west coast of Jutland. You can see what this itinerant larid looked like then in second-year plumage here.

Interestingly, after no sightings for more than three months, JK0P was refound again on 22 February back in the same Oslo park where it was first ringed, and was reported intermittently there and nearby until 16 April. It’s possible, perhaps likely even, that the bird stayed south of its breeding range in at least its first summer, but subsequently it may have returned to Greenland.

My part in JK0P’s story came on 16 January this year with a chance encounter at a private industrial site in east London. If I was pleased to find an Iceland Gull on my patch, I was positively thrilled when I noticed the ring and got photographs showing the code. JK0P was now 1,143 km SW of the original ringing site. I put out the news via BirdGuides and posted a couple of images on social media, but this proved not quite to be the end of the story.

Distance from ringing to recovery sites is 1,143 km.
Once I’d entered details of the sighting into the excellent Norwegian colour-ringing website, I was contacted by Morten Helberg and given chapter and verse on the bird. Morten also mentioned a sighting of a Norwegian colour-ringed Iceland Gull at Loch Oire, near Elgin, Scotland, on 30 April 2013 that was either JK0P or JM0J, the latter bird not having been seen since it was ringed on 4 January 2013. Two days after my encounter, fellow Rainham birder Paul Hawkins told me he saw what may well have been the same Iceland Gull at Egypt Bay, Kent, while from Buckinghamshire Tim Watts sent record shots (see below) of a same-aged bird that closely resembles JK0P at Calvert Lake on 28 November 2014 – photographed near dusk, the bird has what looks like a Norwegian ring but, like the Scottish individual, the code is unfortunately not legible.

This same-aged, colour-ringed Iceland Gull was seen in Buckinghamshire about six weeks before JK0P appeared in London. The ring code couldn't be read but strong plumage similarities suggest the same bird was involved in both sightings (compare field marks in my annotations with images of JK0P above and below. Photos: Tim Watts).
On checking The Migration Atlas, published by the British Trust for Ornithology in 2002, I discovered there are just two previous confirmed recoveries of Iceland Gulls in Britain, and apparently none since:

So JK0P becomes the first ‘recovered’ Iceland Gull in Britain for 60 years, and perhaps it will be seen again before the next journey north. The chances of a sighting from Greenland are effectively zero through lack of observer coverage, but the species’ known breeding range and this individual’s repeat showings in three European countries in as many years all highlight the extensive wanderings of this subtly beautiful larid. If you are lucky enough to find an Iceland Gull on your patch, make sure you check it for rings.

The slightly darker and browner tone to the outer primaries is somewhat suggestive of Kumlien's Gull, but the bird is otherwise typical glaucoides Iceland Gull.

Thanks to Morten Helberg, Peter Rock, Paul Hawkins, Tim Watts, Peter Adriaens and Dawn Balmer and Rob Robinson at the BTO for information and comment on this fascinating bird.

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