4. Storms
Storms can be devastating for seals, particularly those from the north which can strip pups from some of the low-lying islands causing mass deaths. However, seals on some of the higher islands such as Staple and Brownsman are less prone to wave-wash.
5. Hungry mums
Grey seals are ‘capital breeders’, which means that during their stay at the colony in the autumn both females and males fast, obtaining all their energetic requirements from their blubber. Female fasts can be over 20 days, while male fasts can be over 50 days. The longer a male can stay in the colony and defend his territory, the more successful they will be.
6. The first few weeks
It's tough being a seal pup. 30% of pups die within a month and 50% within their first year. Pups are weaned in 18 days, in which time they will have quadrupled in weight. Abandoned by their mother, they spend another 20 days or so on the colony before heading out to sea for an independent life.