The Farne Islands are home to over 25,000 pairs of guillemots in the summer.
A small percentage are bridled guillemots, that is they have spectacle-like markings around the eyes.
The guillemot looks dark brown and white when compared with the razorbill.
Female guillemots lay a single egg and brood it on the rock face as there is no nest. The eggs are conical-shaped to minimise the risk of rolling off the edge and have a special self-cleaning waterproof surface.
Young guillemots are known as jumplings because their first move is to jump off the rocks into the water. We saw only one jumpling last week. Its feet look enormous - all the better for jumping with.
Listen to Sir David Attenborough's BBC Radio 4 Tweet of the Day on guillemots here.