Remember Lesser Black-backed Gull Green YBJB, showing black on all 10 primaries in 2017?
In one of my research projects I’m interested to find out how constant such a primary pattern is across multiple seasons.
I’m happy to find out therefore that this year, the inner primaries P1 and P2 of YBJB are ‘back to a standard pattern’, showing no black.
Both images were taken in the gull colony of IJmuiden Forteiland, the Netherlands, 8 May 2017 and 14 May 2018.
For more images of 2017, see Adult Lesser Black-backed Gull Green YBJB with black on all primaries – 20170508.