Phalacrocorax aristotelis desmarestii Payraudeau, 1826
Common names: Mediterranean Shag [En], Cormoran huppé de Méditerranée, Cormoran de Desmarest [Fr], Θαλασσοκόρακας [Gr]
Pythagorio, Samos ● Greece
Protection status: The subspecies is in the Annex I of the EU’ s Bird Directive and the Mediterranean population of the species (Phalacrocorax aristotelis) is listed in Annex II of the Bern Convention. The species is protected in all the member states of the European Union.
The total population was estimated to be less than 10.000 pairs, half of them breeding in the EU (Eastern coast of Spain, Baleares, Corsica, Sardinia, Tuscany archipelago, Lampedusa, Crete and islets of the Ionian sea). All experts agree on the fact that its population has undergone a decrease in numbers.
Description: The Mediterranean Shag is a subspecies endemic to the Mediterranean basin and Black Sea.
(L 80 cm), greenish-black plumage, has a curved crown-tuft in breeding season.
Biology: It is a seabird species linked to the coast where it breeds in rocky areas. The species is sedentary and partially dispersive, but generally philopatric.
The species nests primarily in winter; however from year to year there seems to be a great difference in nesting periods (Guyot 1984). The laying dates range from November to March depending upon the region, and younger birds breed later, occupying sub-optimal nest sites and having lower breeding success. The commonest clutch size is three eggs and incubation lasts 30 days. The fledging of the chicks lasts for about 53 days.
The subspecies feeds mainly on coastal fishes, from bottom or mid water over rocky or sandy seabeds. During breeding period it forms sparse colonies, nesting in crevices or caves, on ledges or amongst boulders, often a few meters above the sea level. The nest is built with a variety of vegetal materials, and is frequently reused in successive seasons.
The Mediterranean Shag feeds mainly by pursuit-diving, and normally alone. Economically important fish seems to form a very small part of the diet.
Habitat: The species has a strong preference for rocky coasts and islands. It is not normally found far from land. Roost always in the seashore on rocks and stacks.
Threats: Mediterranean Shag is a shy bird which is severely affected by frequent visit to the colonies. (Guyot 1993). The increase of length of the tourist season and their activities close to the breeding sites, the development and the lack of effective protection of some important colonies can represent a critical threat. Birdwatching and research activities can also cause serious disturbance. These threats are not only limited at the colonies but also at roosting places.
Incidental oil spills or illegal washing of tanks are a proved threat (Lambertini & Leonzio 1986) that can have lethal and sub-lethal effects on adults and eggs through eggshell smearing.
Some fishing methods such as gill nets and fish traps, particularly when located permanently close to the sea shore, are responsible of the killing of a significant numbers of shags, as has been reported in Balearic islands (Aguilar 1991).
Favourable habitat (for breeding, roosting and feeding) is most often unaffected, but habitat availability for shags can locally be reduced by developments, illegal trawling, construction of ports, marinas and sea walls, uncontrolled anchoring of yachts and sand extractions for beach regeneration. The latter can strongly affect the Posidonia beds and other benthonic communities where Mediterranean Shag feeds.
Despite legal protection, illegal prosecution of the species is still frequent in some areas.
Distribution: The species breeding range includes all EU Member States along the Mediterranean coast, Gibraltar (UK), Croatia, Albania, Bulgaria, Ukraine, Turkey, Cyprus, Egypt, Libya, Tunisia and Algeria.
BirdLife International, 2002. Species Action Plan for the Mediterranean Shag Phalacrocorax aristotelis desmarestii.