Older, more aggressive bulls may hold several females in a loose territory. During the months prior to the breeding season the seals have been actively feeding - the females to grow the developing fetus to full term, and to build the thick fat layer which will sustain them and their calf for the month or so of fasting which follows the birth. The males also are actively feeding, since they also will fast for the breeding season. Shortly before the birth, the female leaves the sea and picks her birth site. In most cases this site is the same, or close to the place she gave birth the previous year.
Grey seals are very solicitous mothers and defend their pups against any intrusion.
Black-back gulls are attracted to the birth site, no doubt to eat the placenta expelled in the birth process. If one should approach the still helpless pup, the mother drives it off or in some cases kills it. If any male should attend too close, he also is threatened, rebuffed, and finally driven away. The tenured or dominant males enter the breeding group as they form, and attempt to stay in the proximity of females. They do not hold territory, as do the Ottarid seals, nor do they attempt to keep or control the movement of the females.