Spot the difference - Michahellis vs. Cachinnans

"Menekse  - welcome to historic fishermen's market"

Menekşe is a place in Turkey on the sea of Marmara at the western corner of Küçükçekmece (Koo-chook-chek-me-je) where gulls gather because they get fed. This makes it a good place to add Slender-billed Gull to your Western Paleartic list and Caspian Gull to your life list (again, thanks Pedro). This was my first attempt to really try to separate Yellow-legged (Michahellis) from Caspian (Cachinnans) Gull. Chances are I blew off numerous Caspian Gulls before this because I never attempted to find them in flocks of large gulls.

Fig 1. Larus Cachinnans - Caspian Gull

Fig 2. Larus Michahellis - Yellow-legged Gull

Characteristics you should be looking for in 1st winter Caspian according to "Gulls" (Olsen, Larsson):
1) Head - "clean": Compare (<=>) the masked appearance of the young Michahellis
2) Bill - pale base develops in 1st winter. Michahellis bill remains dark throughout first year, These photos are from January, so the Cachinnans has had time to develop this feature.
3) Legs - long, pale bubblegum coloured
4) Neck - long <=> Michahellis in fig 2
5) Gonys - flat
6) Eye - small, dark and to front of head
7)  Plumage, tertials. Worn in Cachinnans, they are supposed to be already replaced in Michahellis. This young Cachinnans feathers look like they've been through a hedge backwards! (although I can't say the YL tertials look fresh either)
8) Plumage, flanks - not quite clean white in this Caspian, but <=> Michahellis in fig 2.
9) Plumage, other - collared appearance contrasting with clean white head
10) Shape - Cachinnans is supposed to be "bulgy" in area behind the legs, but sounds like a tricky ID feature to me.

Still a long way from being expert, or even intermediate, and slightly concerned that interest in large gull ID is dangerously close to the edge. Next thing you know I'll be carrying Kodak charts in my back pocket.

Quick look at Dalbeath Marsh this morning revealed nothing of great interest, although I did add Reed Bunt to the NT1590 list as well as LBB Gull, but which race ...