rokermartin
Well-known member
I have looked at several pics of Whooper and Bewick's Swan bill markings in the last few days and to me the swans clearly show Whooper bill markings.
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Juvenile Bewick's or Whooper Swan (2 Viewers)
- Thread starter IanF
- Start date
SteveClifton
Well-known member
I would tend to agree with you. I haven't seen these two birds but can't understand why they look so small in the field to people who have seen them, yet they do look more Whooper-like in jizz & bill markings.
One of life's little mysteries; especially as Bewick's are supposed to be 'do-able' on size alone.
Looks like it's Whoopers for me too then.
Steve
Bonsaibirder
http://mobro.co/saddinall
Interesting discussion! I have just seen these two swans for the first time today. I can't claim any good experience with juveniles of either species, having never properly studied a juvenile without accompanying adults. It's embarrassing!
I found size and shape very difficult to judge, even after watching them for an hour. They never looked particularly long-necked though and they are small compared to the Mute's!
As has been mentioned, the bill pattern of these swans fits Whooper very well. However the literature I can find isn't very encouraging regarding whether bill pattern can be used to identify juveniles. BWP is fairly non-commital and "Wildfowl" doesn't help much either.
So pictures like Sean Nixon's on the Surfbirds Scarce Gallery (referred to below; from Westleton in December 2008) are quite interesting. Most of the young Bewick's in the Surfbirds gallery have bill patterns which resemble adult Bewick's. But assuming the Winterton juvs are Bewick's Swans, then their bills look similar to the Seaton Pond birds.
[For another example see here: http://www.arkive.org/bewicks-swan/cygnus-columbianus-bewickii/image-A16128.html ]
However there is a subtle difference in the pattern of pink on the upper mandible. In the Westleton picture, both birds have pink which cuts across the bill quite a bit above the nostril (ie between the nostril and the eye) whereas the seaton birds both have the pink cutting through the nostril (I've attached a dodgy field sketch but this is also shown very well on Ian F's first photo).
If the pink on these juvenile swans' bills turns black, then the Westleton birds will end up with a Bewick's' pattern and the Seaton Pond birds will end up with a Whoopers' pattern.
So, is this a reliable feature in juvenile swans? If yes, then they must be small Whooper Swans.
I have noticed while looking at all many swan photos on the web, that Bewick's tend to show more of a bulge below the base of the bill than Whoopers, which helps to make the bill look shorter and deeper-based. They also seem to have a slightly different shape of the feathers at the gape of the bill. I don't know if either of these are consistent features but the Seaton Pond birds look more like Whoopers in both respects.
I found size and shape very difficult to judge, even after watching them for an hour. They never looked particularly long-necked though and they are small compared to the Mute's!
As has been mentioned, the bill pattern of these swans fits Whooper very well. However the literature I can find isn't very encouraging regarding whether bill pattern can be used to identify juveniles. BWP is fairly non-commital and "Wildfowl" doesn't help much either.
So pictures like Sean Nixon's on the Surfbirds Scarce Gallery (referred to below; from Westleton in December 2008) are quite interesting. Most of the young Bewick's in the Surfbirds gallery have bill patterns which resemble adult Bewick's. But assuming the Winterton juvs are Bewick's Swans, then their bills look similar to the Seaton Pond birds.
[For another example see here: http://www.arkive.org/bewicks-swan/cygnus-columbianus-bewickii/image-A16128.html ]
However there is a subtle difference in the pattern of pink on the upper mandible. In the Westleton picture, both birds have pink which cuts across the bill quite a bit above the nostril (ie between the nostril and the eye) whereas the seaton birds both have the pink cutting through the nostril (I've attached a dodgy field sketch but this is also shown very well on Ian F's first photo).
If the pink on these juvenile swans' bills turns black, then the Westleton birds will end up with a Bewick's' pattern and the Seaton Pond birds will end up with a Whoopers' pattern.
So, is this a reliable feature in juvenile swans? If yes, then they must be small Whooper Swans.
I have noticed while looking at all many swan photos on the web, that Bewick's tend to show more of a bulge below the base of the bill than Whoopers, which helps to make the bill look shorter and deeper-based. They also seem to have a slightly different shape of the feathers at the gape of the bill. I don't know if either of these are consistent features but the Seaton Pond birds look more like Whoopers in both respects.
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SteveClifton
Well-known member
I also saw that very same picture in your link, but also came to the same conclusion as you i.e. that these must be considered Whoopers if bill patterns of Juvs 'mirror' those of adults, however I have no conclusive proof of this.
I also agree that it's embarrassing that these are not proving to be so clear-cut as some people would have us believe,
Steve
I always assumed that the bill pattern of juvenile wild swans mirrored that of adults,apart from colour, at least that is my experience. All the juvs I've seen of both species have shown this & accompanied by adults to back up the id. Please correct me if i'm wrong. Cheers, P.
FoghornKinghorn
Durham Recorder
Below is a hyperlink to some other photos taken of the same two swans in question:
http://www.birdforum.net/showpost.php?p=1663821&postcount=11246
Not the "Seaton Pond Swans" but an interesting photo of bill pattern on a Bewick's Swan: http://www.photographersdirect.com/buyers/stockphoto.asp?imageid=934787
Hope this helps,
http://www.birdforum.net/showpost.php?p=1663821&postcount=11246
Not the "Seaton Pond Swans" but an interesting photo of bill pattern on a Bewick's Swan: http://www.photographersdirect.com/buyers/stockphoto.asp?imageid=934787
Hope this helps,
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Southern Frogmouth
Well-known member
Bill pattern is diagnostic for juv Bewick's and Whoopers. There are two things to look at (see Collins Guide for confirmation). 1) The pinkish colour on the bill indicates the ultimate extent of the black that will develop on the adult and the off-white is what will turn yellow - in this repect the picture at http://www.photographersdirect.com/buyers/stockphoto.asp?imageid=934787 is still an obvious Bewick's.
2) The black line along the cutting edges of Bewick's is thick and extends onto the lower mandible. On Whooper it doesn't seem to and is therefore a thinner line.
On this basis the Seaton birds are Whoopers - despite their apparent small size. It is worth considering that both Mute and Whooper vary from 140 to 160cm in length. Also I have seen definite adult Whoopers at Wilstone Res which were much smaller than nearby Mute swans. I would guess that the 140 to 160 cm applies to adults and that 1st-winters might be smaller.
2) The black line along the cutting edges of Bewick's is thick and extends onto the lower mandible. On Whooper it doesn't seem to and is therefore a thinner line.
On this basis the Seaton birds are Whoopers - despite their apparent small size. It is worth considering that both Mute and Whooper vary from 140 to 160cm in length. Also I have seen definite adult Whoopers at Wilstone Res which were much smaller than nearby Mute swans. I would guess that the 140 to 160 cm applies to adults and that 1st-winters might be smaller.
