Whiskered vs Common Tern - Differences? (1 Viewer)

[JayFeatherPL]

Hello,
How can I separate standing Whiskered Tern from standing Common Tern in winter plumage?

I know about the head pattern, but I don't think it's enough. Whiskered should have a black spot behind the eye and Common should have a uniform black cap/head (with white forehead).

But some Whiskered Terns have head pattern very similar to (or identical to, as in bird 3) Common Terns. Here are 3 examples:
Bird 1
Bird 2
Bird 3

But maybe I'm missing something. Would you tell apart Whiskered from Common Tern on head pattern alone? What are your methods helping to separate this two terns?

(Wingbar & bill are also inconsistent features as shown on this thread)

 

[THE_FERN]

Bill is normally shorter, thicker and more wedge-shaped in whiskered

 

[JayFeatherPL]

Bill is normally shorter, thicker and more wedge-shaped in whiskered

Thanks. And are there any plumage features? Because the bill can be a subjective feature, especially for those who haven't seen both of these terns very much...

 

[THE_FERN]

Thanks. And are there any plumage features? Because the bill can be a subjective feature, especially for those who haven't seen both of these terns very much...

Yes. For example head pattern and general structure

 

[JayFeatherPL]

Yes. For example head pattern and general structure

I know about the head pattern, but I don't think it's enough. Whiskered should have a black spot behind the eye and Common should have a uniform black cap/head (with white forehead).

But some Whiskered Terns have head pattern very similar to (or identical to, as in bird 3) Common Terns. Here are 3 examples:
Bird 1
Bird 2
Bird 3

But maybe I'm missing something. Would you tell apart Whiskered from Common Tern on head pattern alone? What are your methods helping to separate this two terns?

 

[wheatearlp]

Thanks. And are there any plumage features? Because the bill can be a subjective feature, especially for those who haven't seen both of these terns very much...

Plumage features differ too, otherwise you wouldn't find images of Whiskered Tern that, to your eye, look like Common Terns.
You can't take one or two features and expect them to be 100% consistent across one species and also maintain 109% difference when compared to another species.
It is a combination of features that differentiate many species from other, superficially, similar species

Whiskered should have a black spot behind the eye and Common should have a uniform black cap/head (with white forehead).

Have you considered telling the birds this? 😉

On a more serious note, of the three pictures you link, neither of the first two, to me at least, look anything like the Common Terns I see in Britain.

 

[Southern Viking]

For birds "on the deck", leg length is worth bearing in mind. Obviously exceptional photos may be found (Commons taking off or Whiskered sitting down etc), but generally Common Tern never look as long legged as Whsikered. For flying birds, as mentioned by others, they're pretty easy but it requires a suite of characters sometimes and experience with at least one or other

 

[JayFeatherPL]

Thanks for help! And what do you think: maybe the black wingbars in Whiskered Terns (as on this thread) are the signs of immaturity?

 

[wheatearlp]

Thanks for help! And what do you think: maybe the black wingbars in Whiskered Terns (as on this thread) are the signs of immaturity?

In the above link, the three birds on the right of the montage aren't the same as the two on the left.
Those on the right look, to me, more like Black Terns - I think I can see a suggestion of the dark 'shoulder-peg' in front of the wing on the top image.

 

[JayFeatherPL]

In the above link, the three birds on the right of the montage aren't the same as the two on the left.
Those on the right look, to me, more like Black Terns - I think I can see a suggestion of the dark 'shoulder-peg' in front of the wing on the top image.

Yes, the 3 birds on the right were already identified as Black Terns. Let's ignore them.
The bird on the branch (on the left) was identified as Whiskered Tern despite having a black wingbar. Do you think the black bar is due to the bird's immaturity?

 

[wheatearlp]

I think the bird in the photo is just showing signs of a faint carpal bar that occurs in some Whiskered Terns in non-breeding plumage.
Overall, the bird just doesn't look like a Common Tern, carpal bar or not.