I was in Stockholm, Sweden for a few days recently to study Baltic Gulls Larus fuscus fuscus. I went mainly for the adult birds but I left being most impressed by the sub-adults.
After being excited about seeing second-calendar years with growing 3rd-generation primaries, some 3rd-calendar years impressed me even more with a few individuals showing 3 moult cycles: 4th-generation inner primaries, 3rd-generation centre primaries and 2nd-generation outer primaries. Very cool.
All images were taken in Stockholm, Sweden around the Skeppsbron area, 7 – 10 August 2015.
For more information about identification and the moult process of Baltic Gulls of this age, see the references at the end of this post.
P1 4th generation, P2 missing/growing, P3 – P7 3rd generation, P8 – P10 2nd generation.
P1 and P2 4th generation, P3 missing/growing, P4 – 6 3rd generation, P7 – P10 2nd generation.
See more images of this bird on Alan Dalton’s blog.
P1 and P2 missing/growing, P3 – P7 3rd generation, P8 – P10 2nd generation.
Inner primaries at least 3rd generation, P6 – P10 2nd generation.
P1 – P5 3rd generation, P6 – P10 2nd generation, mirror on P10.
P1 – P4 3rd generation, P5 missing/growing, P6 – P10 2nd generation.
Plumage development and ageing of Baltic Gull – A. Lindholm & A. Forsten