Yelkouan shearwater is a typical seabird from the unusual group, the shearwaters (Procellariiformes). It is the endemic species of the Mediterranean Sea. Until recently it has been considered as a subspecies of the Manx shearwater (Puffinus puffinus), species widespread in the Atlantic Ocean. As a separated species, yelkouan shearwater breeds from southern France and eastern Algeria to Turkey and Bulgaria. A small number breeds in our offshore islands in the middle Adriatic, on island St. Andrija and on the Lastovo archipelago. The estimation of the breeding population is 300 to 400 pairs, with 50% of the nation’s population breeding in the Lastovo archipelago.
The silhouette of this mid-sized bird is typical shape for seabirds: long, narrow wings that allow an elegant flight and relaxed windsurfing over the waves. The bill is long and thin with a curved tip that helps to retain fish. What characterizes this bird as a member of shearwater group are pipes on the upper side of the beak by which they excrete sea salt from the body. While they are so perfectly adapted to the sea, to be on the land is awkward because they have short and webbed feet that are placed at the back of their body.
Luckily, they only land when it´s time to breed. The breeding colonies are situated on rocky islands and islets where there is no human disturbance or predators, often with other marine species such as Scopoli´s shearwater (Calonectris diomedea). Nests are built in cracks, shelves, or holes in the soil made by rabbits. They lay only one egg per year. Both parents incubate the egg and take care of the nestling that hatches after 50 days. They land on the colony only when they feed the chick and during the night, especially during strong moonlight. The pair is monogamous and it usually last lifelong but they are also very social, so they can often be seen in larger or smaller groups. Individuals are sexually mature at three to six years, and a lifespan is up to 25 years. They fly characteristically very low above the sea surface, rarely higher than 10 m. For food, they usually catch small pelagic fish and squid, on the surface of the sea or diving.
Accordingly to IUCN categories for threatened species, state of the breeding population of yelkouan shearwater in Croatia is vulnerable (VU). It is protected by the Nature Protection Law of the Republic of Croatia, it is placed in Annex I of the Birds Directive and in Annex II of the Bern Convention. All breeding areas are listed as Special Protection Areas (SPA) for Natura 2000 Network and most of them are situated in the protected area of the Lastovo Islands Nature Park.