2CY Baltic Gulls, Stockholm – August 2015

A few weeks ago I was planning a trip to Stockholm, Sweden to go and see Baltic Gulls Larus fuscus fuscus.

The main aim of the trip was to get acquinted with adults but I was secretely hoping that I would also come across 2nd-calendar year birds.

Between the months of May and August, Baltic Gulls of this age can be identified based on their moult which is much more advanced compared to Western Lesser Black-backed Gulls Larus fuscus graellsii and Nordic Lesser Black-backed Gulls Larus fuscus intermedius (see reference at the end of this post).

In June 2013 I was able to identify my first 2nd-calendar year Baltic Gull this way (two actually) and I have been fascinated by this moult pattern ever since.

During my trip to Stockholm I was lucky enough to come across 3 (possibly 4) individuals. Most interesting to see for me was that the inner primaries were already being replaced by third-generation feathers, something that I had not seen before. It made me think of Dutch Lesser Black-backed Gull Green YBSJ which I had seen only a week before and which was still in the process of replacing the outer 4 first-generation primaries. Quite a contrast.

Bird #1

Skeppsbron, Stockholm, Sweden, 7 August 2015.

The white in the scapulars, coverts and tertials contrast well against the faded brown first-generation and the dark gray second-generation feathers. P1 is half-grown while P2 is still present.



Bird #2

Skeppsbron, Stockholm, Sweden, 7 August 2015.

This beautiful bird is much more uniformly colored. Interestingly, P1 to P3 have all been dropped.



Bird #3

Skeppsbron, Stockholm, Sweden, 8 August 2015.

On day 2 of my trip I spent a few very enjoyable hours with local birder Alan Dalton and together we came across this bird. At first I thought that it was the same bird that I saw the evening before but it turned out to be a different individual.

It too is replacing inner primary P1.



Check out the nice images that Alan took of this bird.

Bird #4

Skeppsbron, Stockholm, Sweden, 9 August 2015.

This bird is a bit more difficult to age but after consulting Alan both he and I are leaning towards a second-calendar year. Although the bill coloration is advanced and perhaps more in line with a 3rd-calendar year, the tail pattern, lack of tail moult and the dark eye would suggest a 2nd-calendar year. All primaries are present.





Field identification criteria for second calendar-year Baltic Gull (Gull-research.org)


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