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Bonoparte's Gull, 1st Summer? Maybe? (1 Viewer)

Phil Juvet

Phil Juvet

Well-known member
A different black head than a Laughing Gull. Orange bill at the base and black at the tip. Thanks, Phil
 

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Recent photo?

Definite tern, and looking at the bill made me think Forster's. I then looked at the wing in Sibley, and now I am confused ;)

Niels
 
I'm going with Forster's. As it mirrors our Common Tern in Summer Plumage.
Extreme pedantry aside?
That's my best choice...;)
 
I checked another source: Collins Europe guide which confirmed Sibley: Forster's in summer is supposed to lack the dark wedge in outer primaries, instead showing silvery white primaries ...

Niels
 
For what it's worth, the illustration in Nat Geo for Forster's is not inconsistent with the picture and seemingly much more likely for California than Common Tern as noted by Phil.
 
Common tern: classic summer upperwing pattern of 4-5 retained dark older outer primaries. Forster's has all-white upperside to the primaries.
Interesting to note here also the plainly orangey (not red) bill, this being the sole feature on which another recent problem bird on here was 'identified' as Forster's: http://www.birdforum.net/showthread.php?t=201890
 
Phil´s tern is a Foster´s Tern alright, not an adult but a second summer with darker worn outer primaries. The bill shape/colour/ pattern is more in line with Forster´s as is the broad white (more or less straight and narrower in Common),wedge between the gape and the black cap. Some second summer individuals has white-flecked forehead but some have complete adult like black cap.

JanJ
 
New one on me. Interesting. But...
a) If it's a 2-year-old with old retained outer primaries it should (apparently) be in active inner-primary moult - which there's no sign of here.
b) The inner primaries couldn't be described as silvery-white (which I assume they should be on 2-year-olds as on adults?).
c) The loral line feature seems pretty dodgy if you look at a few photos of common tern, e.g. http://www.birdforum.net/opus/Common_Tern
d) The bill colour's suffering from reflected light so not easy to judge.
e) Extent of black bill-tip isn't too far off normal common.
On the other hand, the bill shape might be nearer Forster's.
 
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JANJ said:
Phil´s tern is a Foster´s Tern alright, not an adult but a second summer with darker worn outer primaries. The bill shape/colour/ pattern is more in line with Forster´s as is the broad white (more or less straight and narrower in Common),wedge between the gape and the black cap. Some second summer individuals has white-flecked forehead but some have complete adult like black cap.

JanJ
Click to expand...
Are you sure Jan? I would think this bird looks quite good for an ad Common. For example (as Buckeye also points to I guess) wouldn't there be a bigger contrast between coverts and remiges? It does also look rather grey. Hard to see also but can't see any hint of grey upper tail?
 
Sorry to bring this one up again but did we come to a conclusion here? I'm at least interested to hear more since this bird still doesn't look like Forster's to me.
 
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I'd like to see the debate go further... since I'd have passed this off a Common Tern. The unmoulted GCs age the bird as a 2nd summer. What's going on with the inner primary - its appears to be contrasting with its near neighbours.
 
so in the spirit of debate....
I'm having trouble finding a Forsters with sush dark greater coverts, or with the inner primaries of the dark wedge so uniformly dark. Also something I've never noticed before - there seems to be a slight difference in the wing tip shape - Forsters more like a Pallid Swift compared to Common Tern's Common Swift. I've only ever seen snow white bandit masked winter birds and never looked that hard at the structure.

Three 1st2 2nd summer Forsters and the mystery tern
 

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My gut reaction is to support Jan, so did a search of images. I came up with these, but I guess you have to be careful with labels. What was surprising was the relatively few 3cy Forster's to be found, but this could be because many see dark primaries and so put them in the 'Common Tern' box

Anyway, what do you think?

http://i.pbase.com/o6/24/752324/1/79444111.1NV50WVJ.DSCN5525.JPG

http://www.flickr.com/photos/nsxbirder/5732121224/

from New York - labelled Forster's
http://www.flickr.com/photos/61123283@N00/2706371033/

Brian S
 
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