Razorbill populations are migratory and lead a predominantly aquatic lifestyle, only coming on land to breed. Understanding the precise number of resident razorbill pairs at Scottish breeding sites is problematic, due to the difficulty of recording nests which are often hidden and inaccessible.

When viewed at close range on the sea, adult razorbills in breeding plumage have an unmistakable shape and pattern of a jet-black bill and head, both of which are often held in a slightly upward position. The thick bill has a blunt end and two distinct white streaks, one vertical (at the tip) and one horizontal (leading up to the eye). In flight, the jet-black upperparts contrast distinctly with pure white flanks, a black pointed tail and wings positioned mid-way along the body. Flight is sustained by constant and rapid whirring beats of rather small wings.

Behaviour

Razorbills are monogamous and frequently share their breeding sites with other auks, such as puffins and guillemots. Breeding sites can be on coastal cliffs, in crevices and on ledges. Razorbills do not generally build nests and females typically lay a single egg per season, often returning to the same site year after year. The special pointed shape of the egg prevents it from rolling off the cliff. When the chick is ready to fledge, it jumps from the ledge and descends almost vertically with its wings whirring until it enters the water on its tummy. The male continues to feed the chick for several weeks.

Adults (male and female) typically forage close to the breeding ground in loose flocks whilst feeding young. Their strong, streamlined body and powerful half-opened wings propel the birds through the water to depths of 25-30 metres to catch small invertebrates or fish such as sand-eels, juvenile cod and herring.

Size

• Length 38-42cm
• Wingspan 60-68cm
• Weight 370-645g

Status

Classified in the UK as an Amber List species under the Birds of Conservation Concern 4 (2015 update) and in the Birds of Conservation Concern in Ireland 2014-2019. Protected by The Wildlife and Countryside Act 1981.

The dramatic regional disparities in recorded populations across Scotland, have lead experts to report that food shortages at specific colonies is the number one reason for breeding failures. The lack of sand-eels has been attributed to producing no young at all, or small and malnourished chicks. The reasons for the lack of sand-eels can be varied and numerous, ranging from a change in ocean temperature, changes in ocean currents and to over-feeding of Herring or a combination of all three. Due to the concentration of birds at breeding colonies,  events such as oil spills can be devastating for a single breeding population.

Distribution

Razorbills are both resident and a migrant in Scotland but can be found in large colonies in the Northern Isles, Outer and Inner Hebrides and on the mainland during the breeding season. While a proportion of Scottish breeders remain in coastal waters, others move south along Atlantic coasts or to the English Channel or move east out into the North Sea.

The total Scottish population of razorbills is increasing, but there are pronounced regional differences. Some colonies experienced catastrophic breeding failures, such as on the Northern Isles in 2004, when the scarcity of sand-eels lead to mass failures of many seabird colonies.

When to see

Mid-March–early September (breeding season).

In mid-to late August the passage of hundreds of birds can sometimes be witnessed from sea-watching headlands

Facts

• The razorbill is the closest living relative to the flightless great auk, which went extinct in 1844. Based on our current understanding, the great auk (which stood almost 1 metre high) is thought to have been widespread throughout the islands of north and west Scotland.
• Razorbill chicks always fledge in late evening, after sunset when they are between 15-25 days old.