request advice re: ID of Tern sp. from 2019 (Shabla Tuzla Lake), Bulgaria (1 Viewer)

[Earnest lad]

I have been looking at some photos from September 2019, and for the first time, noticed the bird in the cropped photo attached. With it appearing to have a stocky bill, I have been wondering as to species. There were lots of other Gulls and Terns around, including a Caspian Tern, Black Terns and Sandwich Terns. I am wondering if I might dare to think it a Gull-billed Tern or not. (I have never seen one of those) If anyone could provide confirmation, or otherwise please, it would be much appreciated. I apologize for the very poor quality of the image.

 

[SJC]

Looks more like a Sandwich Tern with that apparently crest

 

[Richard Prior]

A Whiskered Tern I think.

 

[KenM]

Whiskered Tern length 24-28 cm
Gull-billed Tern “ 35-42 cm
Black H. Gull “ 35-39 cm 😮

Cheers

 

[THE_FERN]

Whiskered Tern length 24-28 cm
Gull-billed Tern “ 35-42 cm
Black H. Gull “ 35-39 cm 😮

Cheers

Not sure what you meant here, Ken. Did you mean you think it's gull-billed because it looks the same size as the gull?

On balance I think it's whiskered. The bill is roughly right for gull-billed, but whiskered can have one this broad and blunt according to Macauley. The photo's overexposed and blurry, but I think the mantle is darker than I'd expect for gull-billed. I can't draw any conclusion about the mud-stained legs. For me, the head pattern is key. This might be possible in gull-billed but it's certainly more usual in whiskered (bill shape and lack of crest role out Sandwich imho)

 

[KenM]

Not sure what you meant here, Ken. Did you mean you think it's gull-billed because it looks the same size as the gull?

On balance I think it's whiskered. The bill is roughly right for gull-billed, but whiskered can have one this broad and blunt according to Macauley. The photo's overexposed and blurry, but I think the mantle is darker than I'd expect for gull-billed. I can't draw any conclusion about the mud-stained legs. For me, the head pattern is key. This might be possible in gull-billed but it's certainly more usual in whiskered (bill shape and lack of crest role out Sandwich imho)

It may be an optical illusion, but to my eye the “subject” bird doesn’t look much smaller than the gull?

 

[Butty]

to my eye the “subject” bird doesn’t look much smaller than the gull?

Given that it's further away, the tern looks as big as or bigger than the gull.

 

[RafaelMatias]

About size and optical illusion, see carefully the relevant attached PDF by the late PJ Grant...

 

[dantheman]

Interesting. Roughly measuring on the photos eg head size, overall length etc the two birds do indeed appear to be of similar size in reality. Although can't completely do it as cropped.

@Earnest lad , do you have the uncropped photo or other photos of the same groups of birds at the same time?

 

[Butty]

the two birds do indeed appear to be of similar size in reality

Impossible to know without knowing the distances of the two birds from the camera and doing a lot of trigonometry.

 

[dantheman]

Impossible to know without knowing the distances of the two birds from the camera and doing a lot of trigonometry.

Note the use of the word 'appear' and request for more/uncropped photos.

 

[THE_FERN]

Back to the bird...

Does gull-billed show this head pattern? I only spent 2 secs checking images. It looked as if no

 

[KenM]

Back to the bird...

Does gull-billed show this head pattern? I only spent 2 secs checking images. It looked as if no

A number of adult and immature Terns are illustrated and shown as having this reversed peak behind the eye to a lesser or greater extent.
Also, apart from how one “sizes” the subject bird to the accompanying BHG, the bill imo looks deeper than the BHG’s?

Cheers

 

[Earnest lad]

A Whiskered Tern I think.

I hadn't thought of Whiskered.

 

[Earnest lad]

Whiskered Tern length 24-28 cm
Gull-billed Tern “ 35-42 cm
Black H. Gull “ 35-39 cm 😮

Cheers

That is so helpful, and suggestive of a bird larger than Whiskered perhaps.

 

[Earnest lad]

Interesting. Roughly measuring on the photos eg head size, overall length etc the two birds do indeed appear to be of similar size in reality. Although can't completely do it as cropped.

@Earnest lad , do you have the uncropped photo or other photos of the same groups of birds at the same time?

Thank you for your suggestion. There were lots of terns at the location. Here is the same image not as cropped and also one of the birds in the flock (mixed flock perhaps) when they had taken to flight.

 

[Earnest lad]

Back to the bird...

Does gull-billed show this head pattern? I only spent 2 secs checking images. It looked as if no

I am not familiar with the species but I checked google images. It seems it doesnt as a rule, although I did see one image of Gull-billed tern that seemed to have a similar head pattern.

 

[THE_FERN]

A number of adult and immature Terns are illustrated and shown as having this
Cheers

Thanks. (I know that, of course). The q is specifically about gull-billed...

...For an example illustration of the point, it's not shown for pictures of gull-billed in the Collins (2nd ed) guide. As I noted, a quick canter through Macauley didn't turn up obvious candidates either but I didn't look thoroughly---hence the q

As to the beak depth/height. I touched on this earlier. This would be deep for the average whiskered tern but perhaps thinnish for gull-billed. Macauley suggests the are some whiskered which approach this appearance

 

[THE_FERN]

Thank you for your suggestion. There were lots of terns at the location. Here is the same image not as cropped and also one of the birds in the flock (mixed flock perhaps) when they had taken to flight.

For me your new picture helps with the sizing. I think this is the same species as the other terns in the group. Most of those are "clearly" (scare quotes because others may disagree) smaller than the gulls. The arrowed bird has its feathers fluffed up giving a misleading impression of large size. ...I'd call them whiskered

 

[Phil Andrews]

About size and optical illusion, see carefully the relevant attached PDF by the late PJ Grant...

See carefully the relevant attached image by the late T Crilly