Colony of Common Murres (Uria aalge)
For its size, the Common Murre has the most densely packed nesting colonies of any bird species; nests may be so close together that incubating adults are actually touching other adults on both sides. Reference www.audubon.org/field-guide/bird/common-murre
The young throw themselves off the cliff, or in this case the sea stack, at about 20 days age before they can fly. They are apparently safer in the water where the adults feed them until they can fly.
Image - Copyright 2018 Alan Vernon.