[Krispo]

Hello,

heading up to Crosby marina in about an hour. there's been a Caspian Gull reported. could someone tell me the info on it please. and how do to tell the difference between a herring gull and a caspian gull?

Thanks,

Kristian

[lou salomon]

which age?

[SteveClifton]

You might need to worry more about separation from Great BB Gull if it's a 1st winter (what age is it?). The reason is they usually display whitish heads, which is often quite strikingly different from most 1st year Herrings.
Also, to separate from GBB Gull at this age, look at;
Bill structure (very thick and heavy on GBBG, longer and often quite droopy looking on Caspian, with more 'parallel' edges to upper and lower mandibles, without a pronounced 'gonys' angle. )
1st years show quite a bit of grey feathering in the mantle/wing coverts.
Tail band-usually blackish-brown, and clearly defined, which is usually very obvious. They retain this feature into second winter too. Neither GBBGull or Herring show such a clear dark tail band.
Tertials often quite plain and dark, paler edged, with little barring.

Adults can be more subtle, so look again at bill structure. They can appear longer bodied with longer folded wings. Also, adults tend to show a darker eye without a pale iris, leading to a beady-eyed look. Primary pattern is also one of the best and most reliable characters at this age, but I bet there'll be other birders there to help you with that. Also look at head shape (can look round-headed, with forehead sloping gently down into bill, which adds to the long-billed appearance), and leg length (usually longer than Herring/GBBGull.)

[Krispo]

ok thanks alot for that steve. i don't know the age sory, which is why i need the birdnews extra details (my subscription has ran out). think it might be about another hour before i go now.

[Krispo]

OK, we are now going after lunch, maybe after the city v preston game.

[marklhawkes]

Originally Posted by lou salomon

which age?

It's being reported as a 3rd-winter (4th cal year)