A search though this photo reveals that they all have the clean white areas going up the back and so are all standard birds.
There were six Cormorants loafing together at Poole Park. The light was from the wrong way but decided to try and photograph them all to see what kind of gular pouch angle they had.
I measured the angles from the photos and the birds seem to fall neatly into two broad groups of angles, the first 65, 70 and 80 and the second 100, 105 and 110.
One could guess that these could be three carbo and three sinensis however this is not the case. Apparently pure carbo must have an angle of less than 65 degrees and pure sinensis an angle greater than 76 degrees. Anything inbetween is not safely identifiable and is thought to include some hybrids.
Obviously my measurements are not going to be as exact as measuring a in hand or dead bird, however it seems that none of these are safely identifiable as pure carbo with two measurements inbetween and four sinensis.
Apparently the gular pouch angle of sinensis is greatest in the east, with those in the west at the smallest end. carbo are also clinal but from north to south with the largest in the south thus making the south of Britain one of the most difficult areas in the world to assign a Cormorant to a sub-species.
These pics are in gular pouch angle order!
Couple of Greylags having a go
Ugliest bird in the world?