They love to stand on the rocks and, particularly if it's sunny, spread their wings to catch
the rays. It's really a sight to see a bunch on a rock, all with their wings spread open!
This was a few weeks ago, when it was not particularly "warm".
Only one felt like spreading his wings that day.
Here is what the reference below says about this habit and their waterproof feathers:
After fishing, cormorants go ashore, and are frequently seen holding their wings out in the sun. All cormorants have preen gland secretions that are used ostensibly to keep the feathers waterproof. Some sources state that cormorants have waterproof feathers while others say that they have water permeable feathers. Still others suggests that the outer plumage absorbs water but does not permit it to penetrate the layer of air next to the skin. The wing drying action is seen even in the flightless cormorant but commonly in the Antarctic shags and red-legged cormorants. Alternate functions suggested for the spread-wing posture include that it aids thermoregulation, digestion, balances the bird or indicates presence of fish. A detailed study of the Great Cormorant concludes that it is without doubt to dry the plumage.
Cormorants are colonial nesters, using trees, rocky islets, or cliffs. The eggs are a chalky-blue colour. There is usually one brood a year. The young are fed through regurgitation. They typically have deep, ungainly bills, showing a greater resemblance to those of the pelicans', to which they are related, than is obvious in the adults.
If you want to know more, check out:
I don't know if it was the light, but I don't remember the bills of some of them looking so bright as they did this year. And, no, I do not know if they gray beaked ones are the male or female.