7 replies to this topic

[Benjamin DeHaven]

Hello!

Today I visited Swan Creek Wetland / Cox Creek DCMF off Curtis Creek in Maryland. Lots of gulls, but so far I have only seen Herring Gulls and Great Black-backed Gulls reported (by birders more experienced than myself). There was also a report of a Least Tern which, obvious even to me, neither of these two are. The one on the left is a pretty standard immature gull, not sure which at this point but I know it is to be expected and I know there are many more like it down on the ground in other images. The one on the right however looks odd to me. Specifically, the bill. Looking at the large gull bills I cannot imagine an angle from which it looks so pointy and "tern-y". What am I looking at here?




Thanks again to all!

Benjamin DeHaven

[Liam]

My initial thought was Royal Tern, based purely off shape.

[psweet]

This may well be a Royal Tern, but given the angle, I don't see any way to rule out Herring Gull. Gull bills look stocky and blunt from the side, but they're quite narrow when you look from the front or back.

[Grandpa577]

The gull on the right is a Great Black-backed Gull. This is particularly evident in the third photo. (Bulk, black upperparts, white edges to secondaries and white tail)

Based on bulk I would think the one on the left would be a Herring Gull.

But based on the pattern of the upperparts which don't seem to show and consistent solid (gray) coloring this would be a young gull. A first summer Herring Gull has a very dark tail even when bleached out. A first year Great Black-backed gull will have a mostly white tail with a black band which by this time of years will be very worn and faded. So the pattern seems to suggest a Great Black-backed Gull on left. Perhaps, first summer female and adult male?

I think the sharpness of the bill is photographic artifact. The wing edges seem to suffer from the same thinness.

[Liam]

Full size photo from the OP's flickr: http://farm8.staticf...690612a5a_k.jpg

[Grandpa577]

As far as looking for terns, the largest tern around here is the Caspian which weighs in at 1.4 lbs. The Herring Gull averages 2.5 lbs and the Great Black-backed Gull 3.6 lbs.

[Grandpa577]

Don't mean to over extend this but I thought this might help. The large tern in the front center is a Caspian. In back is a Great Black-backed Gull (GBBG) and a Herring Gull on far left. What I'd like to also point out is the terns in the air. Their bodies look small compared to their wide wing span - they are gliders compared to the 'C-130 Cargo Plane' GBBG, above.


Caspian Tern_7526m by Grandpa577, on Flickr

[Benjamin DeHaven]

After reading everything and pondering I am forced to lean towards the right side bird being a gull, likely a Great Black-backed Gull. Making this even more likely is after seeing the only other suggestion seeming to be a Royal Tern, I did an eBird search for Royal Terns in this area. There was 1 bird reported by 1 individual about 1 mile from the site my photo was taken from exactly 1 month ago. Other than that there are very few recent sightings, very very few. Add that to the fact I know for a fact the Great Black-backed Gull was present in great quantities I think the answer is almost assuredly the GBBG.

Also, the picture posted by Grandpa577 showing absolute size comparisons is great. If only these were available for every bird combination, but I suppose that's the direction the internet is heading.

Thanks guys!

Benjamin DeHaven