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Hi Cliff,

Thanks for your interesting email. After looking more critically at my own images of juvenile Whoopers yesterday and comparing them with the Idaho bird, I did notice that the extension of pale/yellow on the lower part of the bill is slightly less in your bird than in most Whoopers here. I fully understand the need for the identification of your bird to be absolutely rock-solid before it can be considered an acceptable record, and I can appreciate some of the concerns raised in your email. I will make a point of checking larger samples of Whoopers in the coming week or so, and will let you know what I find.

Incidentally, I feel pretty certain the Idaho bird is a first calendar-year. Icelandic Whooper Swans - the only ones we see in Ireland - acquire an essentially whitish plumage more rapidly than either Bewick's Swan, or the Continental European population of Whoopers. I do not know if there is any variation in this regard among Asian Whooper populations, presumably a more likely source of vagrants in Western USA?

Anyway, first things first. I will see how many (if any?) of our Whoopers match the possibly anomalous features of the Idaho bird. It will be an interesting project.

All the best,

Killian

----- Original Message -----
From: Cliff and Lisa Weisse
To: Killian Mullarney
Sent: Tuesday, January 03, 2006 7:30 PM
Subject: Re: [BIRDWG01] Whooper Swan ID

Killian,

Again, thanks for taking the time to send these photos. This is a potential first state record for Whooper Swan in Idaho. As a member of the records committee I appreciate any insight you can provide to ensure that a solid decision is made regarding this record. There are a couple features of the Idaho Whooper Swan (http://www.octoberweb.com/birds/whooper) that still don't look right to me, at least not for a typical Whooper. I'll do my best to explain my concerns.

The extent of yellow on the bill is less than on any photo of a known Whoooper I've seen. I'm looking at it two ways, compared to the nostril and how much of the bill contains yellow. On all photos of Whoopers (that I've seen so far) the yellow ends more than half way down the lenght of the bill. On the Idaho bird it ends less than half way down the length of the bill. Another way I'm trying to evaluate this character is that the yellow extends to the distal end of the nostril on all Whoopers I've seen photos of. On the Idaho bird the yellow extends to short of half way down the nostril. The place on the bill where the yellow ends seems pretty consistent in the limited photo sample I've looked at. I realize there is variation but I haven't yet seen one that's as limited as the Idaho bird.

Neck structure. I have a fair amount of experience with Trumpeter and Tundra Swans. No expert by any means but I see thousands of swans annually and live in the heart of the winter range of Trumpeter so there are hundreds available for study all winter, occasionally 1000+ at a nearby refuge. In my experience Trumpeters are noticably longer and thicker necked than Tundras. In the photos you sent, as well as the other photos I've found, Whoopers consistently appear even thicker-necked than Trumpeters. The Idaho bird appears very thin-necked in all photos. There are Trumpeters in some photos for comparison and the neck consistently look thin. Posture obviously plays a role in the apparent structure of the neck, as you cautioned in an earlier post, but I can't find any photos of Whoopers (and I've found several that show birds in an alert posture with neck straight up and appearing thinner than Whoopers in other photos) that have such a thin neck.

Others have expressed concerns regading this bird's identity. I'll paste in the most comprehensive here and appreciate any further comments you may have.

I think this one is a Bewick's (Tundra) Swan rather than a Whooper Swan.

Starting with the structure which I feel is key (a Whooper should look very much like a Trumpeter if you black out the yellow on the bill), the neck of this bird is more short and slender as you note -- much less "muscular" in appearance than a Trumpeter or Whooper and more like a Tundra. In terms of posture, the bird also holds its neck more upright in a typical Tundra pose. The back is also more sharply rounded than on the nearby Trumpeters. The net effect is the gooselike posture typical of Tundra.

The forehead is domed farther forward and the bill profile is more dished out, lacking the angular, "Canvasback" appearance of a Trumpeter/Whooper.

In terms of bare parts, the facial skin rises almost straight up from the gape, then curves sharply back to the eye a a thin bridge of skin, rather than extending more straight back to a point at the eye, as one can see on the Trumpeters and which should also be seen on a Whooper.

The yellow on the bill does not extend as far forward as on typical Whooper; rather the extent is typical of Bewick's. Bewick's, and to a lesser degree, Whooper are said to show some variation in the extent of yellow so I would not use this as a diagnostic, but it lines up with the other evidence pointing to Bewick's.

In terms of age, I am not sure if is a young bird coming into adult plumage, or a mud-stained adult. The neck is more pale than I would expect for a juvenile Trumpeter or Whooper in November, but could match a 2nd winter Bewick's/Tundra. The bill colors appear to be fully developed, rather than showing flesh-colored tones as on juveniles.

The feathering on the forehead at the top of the bill does appear to extend farther than I would expect for typical Tundra, but the photos are not very conclusive on this point. Given the other, more well-defined characteristics which all point to Tundra/Bewick's, I would not try to take this single, apparent trait as evidence for hybrid parentage (Trumpeter/Bewick's or Whooper/Whistling?) despite the bird's association with Trumpeters and its being a juvenile.

This does appears to be on the large end of the size range for Bewick's. The body of this bird while swimming does appear at least 10% shorter than the nearby Trumpeters (assuming these photos were taken at long enough range with a zoom lens or scope that the effect of this bird being behind the Trumpeters is negligible). Combined with the shorter neck it would be perhaps 15% shorter if it were stretched out in flight.

So, say 135 cm if these are 160 cm Trumpeters. That is still good-sized for a Bewick's (which average a bit smaller than the Whistling subspecies of Tundra), but within the Bewick's size range of 115-140 cm according to Beaman & Madge's Handbook to Bird Identification for Europe and the Western Palearctic. It would be a bit too small for a Whoopers which range from 140-165 cm ... but of course this depends on | the size of the Trumpeters used for reference. | | Anyway, to sum up, my best judgement is that this is a 2nd winter Bewick's (Tundra Swan), probably a young male given his apparent size & general look.

One final question I have is can hybrid Tundra x Whooper be safely ruled out? I've seen reference to hybrids but don't know whether they've been documented. Any thoughts?

Something my wife noticed, which may or may not be useful, is that the shape of the throat (between the bill and neck along the bottom of the head)seems to differ consistently between Whooper and Tundra. Straight in Whooper, curved outward in Tundra. The difference is subtle but has been consistent in the photos we've checked it in. Since you obviously spend a lot of time studying swans I wondered if you could check this mark for me? I haven't had a chance to use it yet but I will check a bunch of Trumpeters this week and all the Tundras I see next spring.

Regards,
Cliff

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