Gulls - Lisbon District (Portugal), 03/10/2025 (4 Viewers)

[Luís Vieira]

Hi everyone,

I have been at "Praia do Dafundo" today (03/10/2025), a small beach at the entrance of the Tagus estuary nearby Lisbon (Portugal), where I have observed and photographed several gull species. Among these, I am not sure about the birds species in the attached photos:
The first and fourth photos are of the same juvenile that I assume is a Lesser Black-winged Gull (Larus fuscus), but it is not exactly the "typical" juvenile that I am used to seeing. It looks very dark and has different shades of brown (it has a metal ring on the right leg, but it is not readable).
The remaining 4 photos are of immature birds which I presume to be yellow-legged gulls (Larus michahellis), but I am unsure whether any of them could be Caspian gulls (Larus cachinnans). Can you please help me clarify these doubts?

Thanks!

 

[martyrynin]

The plumage of the lesser black-backed confused me as well, but you can see from gull research that scapular pattern does present that way in feb/march.
Structure good for LBB.

Gull Research Organisation

This website deals with the taxa graellsii & argenteus. Comparison of plumages month by month.

gull-research.org

The other gulls are yellow legged.

 

[lou salomon]

Yes, pics 1 and 4 are of a 2cy LBBG, the rest are 2cy YLG (no Caspian in there). Note that these aren't 'juveniles' but late 1st winters, so, if you like - 'immatures'. Juvenile plumage lasts only up to the short time before scapulars (on the 'back' of the bird) start to moult and get replaced for 2nd generation ones; in YLG this happens a few weeks after hatching, in LBBG usually during mid autumn.