Monday, 29 February 2016

Gulls on the patch: late winter update

First-cycle Yellow-legged Gull - numbers of this species are very low on the Thames in winter.
It's been a relatively quiet season for gulls on my study site in east London, with the winding down of food waste disposal into landfill (see here for more background to this). I'm continuing to survey the site, monitoring and counting gulls (and other species) each month, but overall numbers and diversity are a shadow of what they used to be.

Systematic counting does bring small rewards, however, and it's always good to see colour-marked birds and establish their history. Most of those on the Lower Thames site I watch have been ringed by the North Thames Gull Group, a long-standing and stalwart group of enthusiasts who use distinctive orangey-red rings with black four-digit codes (always ending in 'T') to mark their birds. Occasionally, however, gulls bearing the bling of other ringing projects pitch up, and so far this year, for example, I've had two European Herring Gulls from Havergate Island in Suffolk, red VTH (below) and red VKD.

Second-cycle European Herring Gull VTH, ringed as pullus in Suffolk on 29 June 2014 and resighted for the first time on 22 February 2016 on the Lower Thames, 112 km SW.
The map belies the real nature of this bird's movements, as 608 days elapsed between the two sightings at the endpoints of the line.
Occasional birds from continental Europe also appear, and this winter's somewhat meagre haul has included both European Herring and Great Black-backed Gulls from Norway (which also produced a rare colour-marked Iceland Gull last winter), but pleasingly also a banded Caspian Gull - seemingly not from the east European heartland of this species' breeding range in Poland and Ukraine, but probably from a Danish scheme using yellow rings. I've emailed the organiser with details, and will post an update here as soon as I hear anything.

Third-cycle Caspian Gull, the rarest plumage - and also a colour-ringed bird from the Continent!
The ring code is difficult to read but may be VD0G, which would probably tie the bird to a Danish scheme.

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