Red throated divers?

[Dogghound]

Originally Posted by bigdave60dog

You obviously do not come across wintering juvenile Great Crested Grebes. They do vary in the proportion of white to dark on the head. Shape varies according to posture in the water which is a part of the language of these.

Dont assume what I do or do not know! Wintering Juvenile Great crested grebes dont actually exist as birds have moulted their juvenile plumage by this time of yearand look similar to adults. With slight difference between 1st winter and adult plumage. As I said before with GN Diver there is no way you could age the birds in this photo.

The posture, neck length/size and body length looks nothing like a great crested grebe. Great crested grebes do not show a thick black neck side in winter plumage like these birds and gc grebe show paler flanks, unlike these birds. Great crested grebes also tend to sit higher in the water with more of a arched back, unlike the flat backs of the birds in the photo.

Great crested grebe plumage is not highly variable, the greatest variability occurs with 1st winter birds showing variable amounts of dark "juvenile" baring on the face.

Originally Posted by bigdave60dog

Having said that Shetland is the "clincher" for Great Northern Divers.

Well no not really as you could get all three diver species in particuar red throated and great northern. Then you get red necked grebe wintering off Norway, and small number of great crested. This is not far away and birds move between Scandinavia and Britain during the winter. Additionally white billed diver winter off Norway and also occassionally turn up (although I think this species is unlikely). Great northern diver do winter in shetland and good numbers.

Originally Posted by bigdave60dog

The suggestion of White Billed must have come from a book. When you see these they are nothing like the pics.Even from that distance

Are you quite sure? great northern and white billed divers are extremely similar at range when in none breeding plumage (also black throated can be similar). Your look at subtle structural and plumage differences as well as the bill (which is not reliable in all birds). There is overlap in size between the two species and since size can be hard to guage at range with nothing but open water to measure against, it is not always that useful at telling the two apart.

And no funnily enough it did'nt come from a book.

[diggleken]

My two pennoth - I think these are great northerns - if you blow up and sharpen, you can see a hint of plumage detail sufficient to say so.
Firstly the jizz is great northern for their bulk and how they sit in the water, then the neck has a touch of black ring remaining and the neck white amount isnt sufficient for red throats, plus skull pattern isnt smooth and dainty for those either. So probably adult GN.
No way are these Grebes (or Cormorants)!
Cheers
Ken