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Juvenile Neotropic Comorant? Sumner County, Tennessee, 3rd September 2020


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Is this a juvenile Neotropic Cormorant? Found on the morning of 3rd September and the afternoon before at Old Hickory Dam in Sumner County, Tennessee. It was sitting in the same spot both times, on the bank of the river near the dam with no other cormorants near by.

I believe it could be a Neotropic Cormorant over a Double-crested Cormorant due to the overall browner colour, absence of orange lores, angle of gular pouch, presence of white border around gular pouch, pointy covert feathers, and proportionally long tail. It appears its tail may be wedge shaped too, but it's hard to tell from the angle in the photos.

Compared to a confirmed sighting of a Neotropic Cormorant in Davidson County, Tennessee from last year, this cormorant looks nearly identical. Additionally, it looks very similar to a current confirmed Neotropic Cormorant in Cocke County, Tennessee.

I posted this on Reddit and in a Tennessee Birding Facebook group previously, and while a couple of people have agreed it may be a Neotropic, the idea of it being a Neotropic x Double-crested hybrid was also raised. I believe this not to be the case, since what little information about hybrids I've found suggests that one would not have the white border around the gular pouch and may retain the orange lores. However, I'm certainly still open to it being a possibility.

Thanks in advance! :classic_smile:

Cormorant-OldHickoryDam-20200903-2848.jpg

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Cormorant-OldHickoryDam-20200903-2853.jpg

Cormorant-OldHickoryDam-20200903-2868.jpg

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1 hour ago, Kevin said:

It dose look like a possible candidate for Neotropic Cormorant, but my vote is for Double-crested Cormorant.

What suggests it's a Double-crested over a Neotropic or a hybrid? I'm not sure I've ever seen a Double-crested without the orange lores, but I'm still learning as I go along. :classic_smile:

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A bump for this one.

I spent some time first thing this morning trying to figure it out. I was leaning to second year Double-crested (the only cormorant I am familiar with) but moved away for the reasons stated by the OP and started thinking hybrid (no idea how common this is).

The white stripe at the base of the bill may be a red herring but appears to be at the wrong angle for Neotropic (should be more parallel to the bill?).

Hoping someone more expert can shed some light.

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15 hours ago, NorthernKeys said:

What suggests it's a Double-crested over a Neotropic or a hybrid? I'm not sure I've ever seen a Double-crested without the orange lores, but I'm still learning as I go along. :classic_smile:

The angle of the rear end of the gular patch is less-acute than shown by Neotrops. Hybrids exist, however, so, care is required.

DC

NE

These are adults in breeding condition; things get slightly sloppier in youngsters

DC with minimal orange in supraloral area

By the way, if you can get a breeding-condition cormorant to open its mouth, the blue of DC is distinctive.

Edited by Tony Leukering
typo fix
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46 minutes ago, Tony Leukering said:

The angle of the rear end of the gular patch is less-acute than shown by Neotrops. Hybrids exist, however, so, care is required.

DC

NE

These are adults in breeding condition; things get slightly sloppier in youngsters

DC with minimal orange in supraloral area

By the way, if you can get a breeding-condition cormorant to open its mouth, the blue of DC is distinctive.

So it's ether a Hybrid or Double-crested Cormorant?

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Just in case it would help in getting a clearer ID on this cormorant, here's a couple of sources a user from BirdFoum provided me which go over some differences between Neotropic and Double-crested:

http://azfo.org/journal/NECO_2008.html
https://static1.squarespace.com/static/54b9bb6fe4b07b4a7d145b55/t/55b5881be4b07baccbccbb7a/1437960219306/Cormorant.pdf

After looking at these sources, it looks like this cormorant has a more consistent brown colouring, as mentioned in the first source, and a proportionally shorter bill, as mentioned in the second source.

The first source also mentions the supra-loral area on a Neotropic, and explains that it has dark feathering as opposed to the bare orange skin exhibited by Double-crested. Given how dark that area is on this cormorant, I certainly wouldn't rule out Neotropic, but it's hard to tell from my photos whether that's due to feathering or not.

Similarly, the tail is difficult to determine from my photos. From what I can tell, it looks like the tail extends further down than the feet, which would be consistent with what the second source says about a Neotropic, but it's difficult to really tell. Additionally, the tail looks like it could be more wedge-shaped, but my photos are at the wrong angles to say that confidently.

Of course, these observations could be my own wishful thinking, but for the most part, it seems to match up with Neotropic better.

That all said though, the angle of the gular pouch is certainly questionable, and I'm definitely not an expert on cormorants, so I'm not sure how much weight these observations would carry in terms of getting a solid ID.

I would love to hear other people's opinions about this! :classic_smile:

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