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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Sadly deceased diver sp., UK (1 Viewer)

dantheman

Bah humbug
Just the two photos and no measurements unfortunately. Tideline Falmouth last week.

Cheers.
 

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not saying it isn't a GND but I think the bill looks okish for BTD. A good comparison shot of the bills 8th and 9th picture down (you have to scroll down a bit) http://www.birdingworld.co.uk/Norfolk 2010.2.htm

Here's a comparison shot of a GND I photographed which has a much more obvious bulge to the lower mandible and the upper mandible isn't the same length as the lower (something that's more commonly the case with GND) but isn't the case with Dan's bird.

[Edit] not sure if my last paragraph made any sense. What I meant is GND has the upper mandible reaching slightly beyond the lower mandible whilst BTD has both the upper and lower mandible ending at the same point (as is the case for Dan's bird)
 

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i might have been wrong and it is in fact a BTD. bill just looked too heavy for black-throated at first view but after checking some of my pics, it seems to fit...(and would explain the smaller size ;)) note that the 2nd bird (pic 3) has a slimmer bill than the OB's.
on the other hand the OB's bill has such a broad base and looks so triangular...
 

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I have to admit my initial thought was Black-throated, but I just had a quick look and took the pics (I seem to recall foot length is almost diagnostic?, although I didn't attempt to measure this at the time). It didn't leap out at me as a GND at the time, although admittedly it never was going to do that in it's current state of health. (The slightly pot-bellied appearance and possibly the way the bird is arranged (the rocks weren't quite a flat surface) may also be contributing to a slightly odd appearance which threw a few people on here ...)

It should also be noted that either species is equally likely at this location at this time of year (eg this week now c.30 BT and 10+ GND)

Thankyou for the comments.
 
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Cause of death is of course going to be unknown for this bird, but rather worrying is the fact that c.50 Shags and a diver sp. were observed to be caught in a fishing net just offshore here this morning (not by me, although I've seen some photos), presumably drowned. Looking forward (not) quite possibly to a plentiful supply of tideline corpses in the next few days ...


:-C
 
no, peter, not gavia immer has a rosy coloured bill but podiceps cristatus ;)
i've just checked some images and i think i'll sway back to great northern diver/common loon: it's not so much the thickness of bill but more the shape: black-throated has a more parallel edged bill and a curved culmen, in GND it generally looks more triangular, like in the OB. as for size, some small GNDs can be as small as BTD. another thing that might count (but i haven't found it as separation feature) is the feathering reaching to the middle of the nostril in the OB, as in most GND pics, while in BTD in most it doesn't reach the middle of nostril. the nostril itself tends to be more split in GND than in BTD - see the OB pic, so this might be enough to sustain my initial feeling of it being a gavia immer.
 
no, peter, not gavia immer has a rosy coloured bill but podiceps cristatus ;)
i've just checked some images and i think i'll sway back to great northern diver/common loon: it's not so much the thickness of bill but more the shape: black-throated has a more parallel edged bill and a curved culmen, in GND it generally looks more triangular, like in the OB. as for size, some small GNDs can be as small as BTD. another thing that might count (but i haven't found it as separation feature) is the feathering reaching to the middle of the nostril in the OB, as in most GND pics, while in BTD in most it doesn't reach the middle of nostril. the nostril itself tends to be more split in GND than in BTD - see the OB pic, so this might be enough to sustain my initial feeling of it being a gavia immer.

Now, thats funny!

Your arguments seem to point to Black-throated (as I believe it is), and yet you reach the conclusion that it is Great N......

The lack of 'gony' (the slightly angled point on the lower mandible, which gives G.N.D. that slightly upturned look of the lower mandible) is typical of B.T.D.

And the fact that the feathering does not nearly extend as far as the mid- or end of the nostril as it habitually does on G.N.D., also strongly suggest that we are looking at a dead Black-throated.

Divers are indeed in the eyes of the beholder;)
 
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My immediate reaction on that bill was Black-throated, and after reading all the comments it remains my verdict.
 
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