Monday, 13 July 2015

Presumed Baltic Gull (Larus fuscus fuscus)

As you may have already read on my previous post, last Saturday was a good day at Shawell. Amongst the 1000+ Lesser Black-backed Gulls was a really smart second calendar year gull, which took my eye. I have read the paper 'Field identification criteria for second calendar-year Baltic Gull' several times and so when I saw this gull had really black primaries my alarm bells started to ring. Luckily I was able to get a bit of video footage of it, which is not easy on the working area of the tip.




Second-calendar year Baltic Gulls have a different primary moult strategy to the same age Lesser Black-backed Gulls (graellsii and intermedius). Most Baltic Gulls moult during their time in their winter quarters and so arrive back in Europe with a fresh set of second-generation primaries. In contrast Lesser Black-backed Gulls moult their primaries in September. So basically second-calendar Baltic Gull is identifiable on primary moult timing. There are no known photographs of either graellsii or intermedius with a full set of second-generation primaries as early as July. Therefore I feel confident to call this gull a Presumed Baltic Gull. Presumed because it doesn't have a nice colour-ring from a Baltic Gull breeding colony. It may prove acceptable without the ring, but time will tell on that score.

Thanks for looking.


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