Reproduction

Pairs form for life and have a strong bond. The two will bond by touching bills and preening one another. Females may mate with other males outside of their pairing while their bonded mate cares for their eggs.

Nesting takes place on a cliffside or offshore rock stack. Razorbills often do not build a nest instead just depositing their eggs on to narrow ledges on these sites. If a nest is built it is formed from pebbles and grass.

They have a pear-shaped egg which helps to stop it rolling off. Eggs are colored white with brown spots. Despite these adaptations many legs are left each breeding season. Predators of eggs include gulls.

One egg is most common but on a rare occasion there may be two.

Both parents work together to incubate the eggs over the 32-39 day gestation period. After hatching they will both bring the chicks food. Parents may bring as many as 20 fish to the chicks on each visit. The chicks are brooded for 9-10 days after which they can maintain their own warmth.

Chicks leave the nest 14 to 25 days after they hatch. They will follow the adults to a cliff edge and flap down to the water as they can not yet fly.

Sexual maturity is reached between 4 and 5 years old.

Behavior

When swimming in the water they are often observed with their tail sitting vertically.

During winter these birds form flocks which can be found offshore. These may include a range of other species from the genus Uria.

Their vocalizations include low croaks or growls. At sea the chicks make a piping noise.

These birds will only come to the shoreline to breed. Outside of this they remain at sea.

Predators and Threats

Natural predators of these birds primarily target chicks and eggs. These may include mammals such as the red fox and birds such as the raven or gull.

Humans threaten the population of razorbills through overfishing, pollution and entanglement within nets. Their habit of living near the shoreline also leaves them vulnerable to oil spills. These affect their ability to feed and fly.

Climate change is believed to be leading to a decline in this species. This is due to rising temperatures which has reduced the availability of sandeels, one of their main food sources.

Large storms may prevent them feeding and can cause mortality in adults.

An emerging risk is collision with wind turbines.

In parts of their range they are threatened by introduced predators such as rats and mink.

Quick facts

The name of these birds comes from the shape of the bill which resembles a cut-throat razor.

Razorbills are thought to be the closest living relative of the now extinct great auk which was last sighted in 1852.