large black diving birds

large black diving birds

Observation - large black diving birds - UK and Ireland. Description: From the distance I thought these were cormorants, but on the photo they look more like gannets (bea

From the distance I thought these were cormorants, but on the photo they look more like gannets (beak, overall shape), but they are black. Then I thought guillemot, but I miss the white parts (even for the black guillemot). The birds were diving from the air, some swimming on the surface.
On the second photo they are seen together with gulls and some ducks, and I think the most right one swimming is also my mystery bird.