Basic Principles
Two species of storm petrel breed around Britain and Ireland: European and Leach’s Storm Petrels. Some 70,000-250,000 pairs of European breed up the west coast from Scilly, along western Ireland to the Scottish islands. Leach’s breeds in small numbers on the Stags of Broadhaven off the west coast of Ireland, and on several of the Scottish islands.
There are large colonies of European (150,000-400,000 pairs) with smaller numbers of Leach’s (10,000 pairs) in the Faroe Islands, and colonies of European (50,000-100,000 pairs) and Leach’s (80,000-150,000 pairs) in Iceland. Small colonies are found elsewhere in coastal Europe.
Breeding activity mainly occurs in May-September, after which both species migrate south for the winter. At this time breeders from the Faroes and Iceland might pass through British and Irish waters. Leach’s…