Common guillemots ©Mike Snelle

Bridled Common Guillemot

(Bridled) common guillemot ©Mike Snelle

Guillemot (winter-plumage)

Guillemot (winter-plumage) ©Tom Hibbert


Scientific name: Uria aalge
Guillemots really know how to live life on the edge – quite literally! They nest tightly packed on steep ledges and cliffs around the coast. This may sound like a strange nesting spot, but it keeps them safe from predators. Thankfully these birds aren’t afraid of a little cliff diving – at three weeks old, guillemot chicks jump off the cliff into the sea!

Species information


Length: 38-45cm
Wingspan: 64-73cm
Weight: 850-1130g
Average lifespan: 23 years

Conservation status

Classified in the UK as Amber under the Birds of Conservation Concern 5: the Red List for Birds (2021).

When to see

March to July


These chocolate-brown birds nest in noisy, tightly packed colonies on steep ledges around the coast. They have a very small territory, so small that it only extends a beak’s-length around its nest! Female guillemots lay a single egg a year and once its chick is three weeks old, it will dive off the cliff into the sea with its father. The father will look after the chick in the sea until it is old enough to look after itself. Guillemots eat fish, crabs and molluscs, diving down into the sea and using their wings to swim after their prey.

How to identify

The guillemot is chocolate-brown above and white below. A 'bridled' form occurs, where the eye is ringed with white, which extends as a line towards the neck. In winter, guillemots have white faces. The similar-looking razorbill is blacker in colour, and has a thicker and shorter bill.


Nests on coastal cliffs, mostly in the north of England and Scotland. In winter, it is present offshore around most of the UK's coastline.

Did you know?

Guillemot eggs are very narrow and pointed at one end (pyriform, or pear-shaped). The purpose of this shape is still debated, but one leading theory is that this shape makes them more stable, reducing the risk of them rolling off the perilous cliff ledges where they are laid! Guillemot nesting territories are probably the smallest of any UK bird, extending only a beak's-length around their nest.