Most only deign to come ashore to breed - at that time, they are decidedly sociable. Our penguins come ashore at night over much of the year, but are included here. However, gulls, terns, shags, and skua, who are ashore much the day, are covered with the coastal birds. Seabirds have evolved a host of characteristics and habits to cope with life far from land. Most have glands which secrete oil, used to waterproof the feathers when the birds preen.
Outer plumage is close-knit to help keep the down underneath dry.
There's no shelter from the elements at sea. Layers of fat, and rounded body contours help preserve heat. Webbed feet, like divers flippers, are the norm, for efficient paddling through. However, this has drawbacks on land. Many seabirds are quite ungainly ashore.