P.c.sinensis....? (1 Viewer)

[KenM]

Having read CF's post, it would appear that there are no images of ''white-headed rock nesting'' Cormorants. Odd when you consider how attractive this ssp might be, to any erstwhile photographer? Perhaps a trip NOW to any suitable rocky coast might yield a good image or two...assuming of course that they are not all nesting in trees?

 

[Mark Lew1s]

Or - as I suggested, that they've lost their white heads by the time they are breeding.

 

[HH75]

I can recall seeing large numbers of white-headed birds at Dunkettle near Cork city on at least one spring date a few years back. They were far too distant for photography, but seemed to be carbo anyway...or, at least, given the rarity status of sinensis here, it is most unlikely most were not carbo. I ought to have noted the date, yes, but I certainly recall that the vast majority of adults gathered there had white heads to some extent. Admittedly, they don't breed at Dunkettle, they were on a rock spit where the river Lee meets Lough Mahon, a saline area of Cork Harbour, but it is likely that they were gathered there immediately prior to breeding, so this may even have been as early as February for all I can recall.

 

[KenM]

Or - as I suggested, that they've lost their white heads by the time they are breeding.

Once more Mark/Harry, is there a consensus on my last posted "Belfast" image, that it's GA is compatible with sinensis on current understanding?

Cheers

 

[Mark Lew1s]

See post 20 ken.

 

[KenM]

The image is from the Baltic, as pointed out above - but it does show a group of white headed, non tree nesting cormorants.

Correct....but not cliff nesting! (there doesn't appear to be any).


I'm no expert in cormorant moult but I don't see why 3 weeks is out of the question. I don't see whats so illogical about a bird not retaining it's breeding plumage throughout the breeding season? Why should that be illogical?

We're not talking about throughout the breeding season....we're talking about prior to the onset.


The bird in your last photo certainly looks better for sinensis than the other two (presumably the middle bird in your first photo?). However I caveat that heavily based on the less than perfect angle, and of course the possibility of a hybrid.

I've examined grabs from the film clip and ascertained that all (5) of the Cormorants have GA in excess of 90 degrees, thus logical to assume that they are ''probably'' from a closely related group (sinensis).

I'm not sure what you're driving at here Ken - what relevance do the birds you saw in the 70's have? Are you suggesting that these birds never had white heads?

Correct, Wherever there is ambiguity and conjecture, if possible, do your own research. Being present at various English Channel/Atlantic/Irish Sea coastal points during what would be ''prime time'' during the seventies, and never observing frosting let alone white heads, leads me to believe that the current science ssp separation on this taxa is at best a little woolly.


In response to Charles - I think that shots of cormorants in the height of the breeding season would be little help - if they lose their white heads in April, (and coastal nesting birds are highly synchronous) then we're unlikely to find many shots of white headed carbo in the height of the breeding season.

I can't talk about CF's perspective, but once again, I'm not talking about the height of the breeding season, merely the prior to, and onset.

cheers

 

[smiths]

Having read CF's post, it would appear that there are no images of ''white-headed rock nesting'' Cormorants.

The internet is a big place...
Here are 13 different white-headed carbo 'on the rocks' - all from Iceland:

https://www.flickr.com/photos/omarrun/5488876153
https://www.flickr.com/photos/27053521@N07/2998411889
https://www.flickr.com/photos/jonina_oskarsdottir/6959693115
https://www.flickr.com/photos/sindri_skulason/2311326804
https://www.flickr.com/photos/hvanneyri/3263397691
https://www.flickr.com/photos/eyfim/8376318173
https://www.flickr.com/photos/omarrun/16603494072
https://www.flickr.com/photos/hvanneyri/3321028808
https://www.flickr.com/photos/omarrun/15984354653
https://www.flickr.com/photos/kjoinn1/2428677451
https://www.flickr.com/photos/27053521@N07/3284582836
https://www.flickr.com/photos/27053521@N07/3281369272

I'm sure there are many more examples.

 

[CharlesFentiman]

I am very pleased to see those images, thanks Smiths, they are very helpful. I too have found examples of Carbo type individuals with a frosting due to the white filoplumes during the breeding season. From the dates of the photos from Iceland and a comment with one it seems that they just starting to develop these white feathers. The images from Iceland do not approach the stark white heads of Sinensis type birds. Other posts on the thread suggest that these feathers are lost quite quickly while the adults are still at the breeding sites.

It is therefore most unlikely that such birds would show white heads when away from breeding areas. Kens memory of not seeing white heads prior to the arrival of Sinensis seems to be correct (and fits with my own recollection). White headed individuals can now be seen through much of the winter and this coincides with the appearance of tree colonies in the SE of England and as far as I can make out these are Sinensis type birds. Presumably those that believe that these colonies are mixed Carbo and Sinensis do so based on the basis of sound evidence. It would be great if they would share how they reached this conclusion. I am guessing that some detailed analysis has been done but since Sinensis is smaller and finer billed it seems surprising that the Rutland birds are all the same size.

 

[Mark Lew1s]

Nothing woolly, or ambiguous, about this:

http://web.tiscali.it/cormorants/pdf/Stuart_ardea2004.pdf

I see loads of white headed carbo cormorants up here in N E Scotland. Sinensis is a description spp up here so is rare - and all of our cormorants are coastal/cliff breeders. For all of these birds that I check, the gular angle conforms with carbo. White heads start to appear in January - and are at their most frequent in February, and some of these birds show pretty extreme amounts of white. As such carbo birds do, frequently, show white heads, away from the breeding areas.

Charles, this paper touches on the evidence used to assess racial ID and therefore the mixed nature of the colonies.

http://www.britishbirds.co.uk/wp-content/uploads/article_files/V100/V100_N05/V100_N5_26_36.pdf

 

[CharlesFentiman]

Charles, this paper touches on the evidence used to assess racial ID and therefore the mixed nature of the colonies.

http://www.britishbirds.co.uk/wp-content/uploads/article_files/V100/V100_N05/V100_N5_26_36.pdf[/QUOTE]

Thanks Mark, this seems interesting and the numbers of birds nesting in inland colonies is certainly impressive and it will be interesting to see how this develops. They have become quite a feature along the Thames and can be seen commuting in to feed along the Thames, even during the peak of the breeding season!

 

[KenM]

The internet is a big place...
Here are 13 different white-headed carbo 'on the rocks' - all from Iceland:

https://www.flickr.com/photos/omarrun/5488876153
https://www.flickr.com/photos/27053521@N07/2998411889
https://www.flickr.com/photos/jonina_oskarsdottir/6959693115
https://www.flickr.com/photos/sindri_skulason/2311326804
https://www.flickr.com/photos/hvanneyri/3263397691
https://www.flickr.com/photos/eyfim/8376318173
https://www.flickr.com/photos/omarrun/16603494072
https://www.flickr.com/photos/hvanneyri/3321028808
https://www.flickr.com/photos/omarrun/15984354653
https://www.flickr.com/photos/kjoinn1/2428677451
https://www.flickr.com/photos/27053521@N07/3284582836
https://www.flickr.com/photos/27053521@N07/3281369272

I'm sure there are many more examples.

Thanks for the images Smiths.....apart from the first image, (which was intermediate), the other 11 images cosmetically are more a suggestion of "frosted" rather than being contrastingly white-headed as per the HMS Belfast birds. Also the remit was "sinensis type" sitting on nest, on a rock face (evidence of breeding in situ.), rather than occasional "frosted" Winter dispersal shots of birds sitting on rocks. (Just the one image would suffice).

....and Mark I would be extremely keen to see an image of you're "solid white-headed sinensis type birds, sitting on a "rock" nest...so next time you're out with the camera, a conclusive shot would be nice.

Cheers

 

[KenM]

The internet is a big place...
Here are 13 different white-headed carbo 'on the rocks' - all from Iceland:

https://www.flickr.com/photos/omarrun/5488876153
https://www.flickr.com/photos/27053521@N07/2998411889
https://www.flickr.com/photos/jonina_oskarsdottir/6959693115
https://www.flickr.com/photos/sindri_skulason/2311326804
https://www.flickr.com/photos/hvanneyri/3263397691
https://www.flickr.com/photos/eyfim/8376318173
https://www.flickr.com/photos/omarrun/16603494072
https://www.flickr.com/photos/hvanneyri/3321028808
https://www.flickr.com/photos/omarrun/15984354653
https://www.flickr.com/photos/kjoinn1/2428677451
https://www.flickr.com/photos/27053521@N07/3284582836
https://www.flickr.com/photos/27053521@N07/3281369272

I'm sure there are many more examples.

Thanks for the images Smiths.....apart from the first image, (which was intermediate), the other 11 images cosmetically are more a suggestion of "frosted" rather than being contrastingly white-headed as per the HMS Belfast birds. Also the remit was "sinensis type" sitting on nest, on a rock face (evidence of breeding in situ.), rather than occasional "frosted" Winter dispersal shots of birds sitting on rocks. (Just the one image would suffice)

....and Mark I would be extremely keen to see an image of you're "solid white-headed sinensis type birds, sitting on a "rock" nest...so next time you're out with the camera, a conclusive shot would be nice.

Cheers

 

[Mark Lew1s]

Thanks for the images Smiths.....apart from the first image, (which was intermediate), the other 11 images cosmetically are more a suggestion of "frosted" rather than being contrastingly white-headed as per the HMS Belfast birds. Also the remit was "sinensis type" sitting on nest, on a rock face (evidence of breeding in situ.), rather than occasional "frosted" Winter dispersal shots of birds sitting on rocks. (Just the one image would suffice).

....and Mark I would be extremely keen to see an image of you're "solid white-headed sinensis type birds, sitting on a "rock" nest...so next time you're out with the camera, a conclusive shot would be nice.

Cheers

I think if you're going to use quotation marks at me, then you have to quote me!

I've never claimed to have, or be able to get, pictures of solid white headed sinensis type birds sitting on rock nests. I'm saying that I see white headed cormorants that have gular angles that conform with carbo. If you're not going to read what people post, what is the point in discussing this with you?

Also, the burden of proof is definitely with you. Whatever aspect of the current understanding of cormorant ID it is that you're challenging (and it still isn't entirely clear), YOU are the one that needs to back it up with some evidence. If you think that a half baked google image search, coupled with what you remember from your holidays 40 years ago is enough to challenge what we know, then you are way off the mark.

I'm all for pushing the boundaries, but it needs to be done properly.

Anyway, it seems that whatever it is you've decided, you've decided it, and there's very little point in discussing it any further with you. I'm out.

 

[lupokatja]

I would definitely id the birds in post #1 as ssp. carbo in the Netherlands, and I see no reason to really suspect ssp. sinensis for the bird in post #8 too.

Lutzen Portengen

 

[KenM]

I think if you're going to use quotation marks at me, then you have to quote me!

I've never claimed to have, or be able to get, pictures of solid white headed sinensis type birds sitting on rock nests. I'm saying that I see white headed cormorants that have gular angles that conform with carbo. If you're not going to read what people post, what is the point in discussing this with you?

Also, the burden of proof is definitely with you. Whatever aspect of the current understanding of cormorant ID it is that you're challenging (and it still isn't entirely clear), YOU are the one that needs to back it up with some evidence. If you think that a half baked google image search, coupled with what you remember from your holidays 40 years ago is enough to challenge what we know, then you are way off the mark.


I'm all for pushing the boundaries, but it needs to be done properly.

Anyway, it seems that whatever it is you've decided, you've decided it, and there's very little point in discussing it any further with you. I'm out.

During the '70's there were Marsh Tits and Willow Tits breeding in my locale, the Willow Tits had disappeared by the mid-late '70's, and the Marsh Tits followed during the eighties. this is fact, and their decline is well documented.

By the same token during the '70's, when perhaps you were "throwing the rattle out of the pram?", I had only observed "Black" cormorants...fact!

If there was any "Peppar and Salt" dusting on any of the birds in my scope, it must have been so minimal to the point of not being apparant....white-headed birds....absolutely none were seen.

Fast forward to the present...a conservative estimate, most of the birds that I see flying over my abode, almost daily, and when I go into "Town" along the Thames foreshore have varying degrees of "frosting", something that would not have occured 40 years ago.

PS in future, when sitting comfortably down with your "protractor", make sure whilst plotting the "gular" degree angle, that your gonads are correctly aligned, as any sudden movement might cause acute discomfort.

Cheers

 

[HH75]

By the same token during the '70's, when perhaps you were "throwing the rattle out of the pram?", I had only observed "Black" cormorants...fact!

I must state that this is most disingenious. It is one thing to have one's opinion dismissed due to being a callow youth in one's teens, at a stage when (if we are limiting this discussion to birding) one doesn't yet have the field experience or in-depth knowledge of the literature. It is quite another to use Mark's age against him here when he is a man in his 30s!
By that token, we should just dig out a 97 year old birder from an old folks' home and let him tell you that your opinions aren't worth the same as his, you young people these days were all the same etc etc...

If there was any "Peppar and Salt" dusting on any of the birds in my scope, it must have been so minimal to the point of not being apparant....white-headed birds....absolutely none were seen.

Fast forward to the present...a conservative estimate, most of the birds that I see flying over my abode, almost daily, and when I go into "Town" along the Thames foreshore have varying degrees of "frosting", something that would not have occured 40 years ago.

Okay, given that sinensis are still rare in both Ireland (personal observation, plus the rate at which they are reported, though with the proviso that not many birders seem to look for them) and NE Scotland (as per Mark Lewis), then I think you will agree that 'white-headed' birds seen in both areas are probably not either pure sinensis (breeding true as a form in some unknown areas in either region) or due to significant introgression from sinensis into local (coastal) carbo populations. Yet we have both stated that such white-headed birds do exist here, and, in my own case (I can't speak for Mark), I first started to notice them in the early to mid 1990s. Why didn't I notice them earlier? Well, I didn't really start looking too hard at them until I became a proper birder in my teens.

PS in future, when sitting comfortably down with your "protractor", make sure whilst plotting the "gular" degree angle, that your gonads are correctly aligned, as any sudden movement might cause acute discomfort.

Gular patch angle is the singlemost important feature in attempting subspecific identification of (Great) Cormorants. I don't know what connection there is, in your mind, between this feature and gonads, and I am not sure I wish to know either... :eek!:

 

[Teamscotch]

I think this my favourite Bird Forum thread for a long time. Kudos!

 

[smiths]

Some more links to photos of white-headed carbo.
These are from the colony at Little Roberts Island, Maine, USA, and were taken in March - April (i.e. early breeding season):

http://4.bp.blogspot.com/-g9qTLQbKvs0/VQH4uxKnwiI/AAAAAAAAB4c/Lnh0p4Xbr-g/s1600/IMG_2926.JPG
http://3.bp.blogspot.com/-J3gQSr66i78/VQH6AdhFiAI/AAAAAAAAB4s/-p8jnLQww14/s1600/IMG_2930.JPG
http://2.bp.blogspot.com/-IaLsz4S3_SA/UWia_InM1WI/AAAAAAAAEKM/hOXM8Tv3x9Y/s1600/IMG_0810.JPG
http://4.bp.blogspot.com/-opvsxvmlrLk/UWibCVdpG2I/AAAAAAAAEKU/SjXfP39hh7M/s1600/IMG_0764.JPG

 

[KenM]

Yes thanks for that smiths.....therein lies my problem, If these are deemed as P.c.carbo they are at best showing just a light dusting of white, far removed from sinensis which appear almost opaquely white!

Not only that, but they sinensis, show a marked preference for fresh/semi saline water for nesting, and only do so between ground level (reeds) and trees, unlike the darker types carbo which appear to be exclusively cliff nesters. That constitutes an evolved "major" difference in breeding requirement.

Therefore there is a degree of confusion in my mind as to what constitutes carbo/sinensis, it has been stated that carbo is bigger than sinensis, if that is the case (this might be attributed to diet, ie marine fish producing a larger ssp) than it's smaller freshwater "cousin".

Thus it would appear that there are no images of "truly" white-headed sinensis types, sitting on cliff-top nests in a marine environment?

FWIW Smiths....life is too short for shame!.....I rarely experience it.

 

[HH75]

Not only that, but they sinensis, show a marked preference for fresh/semi saline water for nesting, and only do so between ground level (reeds) and trees, unlike the darker types carbo which appear to be exclusively cliff nesters. That constitutes an evolved "major" difference in breeding requirement.

From memory, the late Clive Hutchinson's Birds of Ireland refers to tree-nesting carbo here, in the west of the country I think, but I'd have to take another look. Plus, at many freshwater colonies in Britain pioneered by sinensis, carbo are now dominant. So perhaps not as 'major' a difference in breeding requirements as you imply.