Common Shag

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Image:Common Shag.JPG

Common Name: Common or European Shag
Scientific Name: Phalacrocorax aristotelis

Size: 39 inches (68-78 cm); 95-110 cm wingspan

Habitat: Eurasia and Africa; It breeds around the rocky coasts of western and southern Europe, southwest Asia and north Africa, mainly wintering in its breeding range except for northernmost birds. The European Shag can readily be seen at the following breeding locations between late April to mid-July: Farne Islands, England; Fowlsheugh, Scotland; Runde, Norway; Iceland, Faroe Islands and Galicia. The largest colony of European Shags is in the Cies Islands, with 2,500 pairs (25% of the world's population).

It occupies marine habitats but does not usually occur far from land. It shows a strong preference for rocky coasts and islands with adjacent deep, clear water, and forages over sandy and rocky sea beds. It also prefers sheltered fishing grounds such as bays and channels, although it generally avoids estuaries, shallow or muddy inlets and fresh or brackish waters.

Status: Least Concern. Global Population: 230,000 - 240,000 mature individuals. The overall population trend is decreasing, although some populations may be stable. This species is persecuted (e.g. shot, intentionally drowned or poisoned) at commercial fisheries and fish farms as it is perceived to be a threat to fish stocks. It also suffers predation at nesting colonies by introduced American mink, it is vulnerable to coastal oil pollution, locally suffers from accidental entanglement and subsequent drowning in gill-nets (fishing nets), and is susceptible to the Newcastle disease so may be threatened by future outbreaks of the virus.

Diet: A wide range of benthic, demersal and schooling, pelagic fish. Sandeels (Ammodytidae) are the dominant prey of birds in British and some Spanish populations. These are usually caught at, or near, the sea bed. Foraging rarely occurs inland.

Breeding: It has a longish tail and yellow throat-patch. Adults have a small crest in the breeding season. It is distinguished from the Great Cormorant by its smaller size, lighter build, thinner bill, and, in breeding adults, by the crest and metallic green-tinged sheen on the feathers. The shag also has a lighter, narrower beak; and the juvenile shag has darker under parts.. The European Shag's tail has 12 feathers, the Great Cormorant's 14 feathers.

It breeds on coasts, nesting on rocky ledges or in crevices or small caves. The nests are untidy heaps of rotting seaweed or twigs cemented together by the bird's own guano. The nesting season is long, beginning in late February but some nests not starting until May or even later. Three eggs are laid. Their chicks hatch without down and so they rely totally on their parents for warmth, often for a period of two months before they can fly. Fledging may occur at any time from early June to late August, exceptionally to mid-October.

Cool Facts: The green sheen on the feathers results in the alternative name "Green Cormorant". In Britain, this seabird is usually referred to as simply “the Shag”.

The European Shag is one of the deepest divers among the cormorant family. Using depth gauges, European Shags have been shown to dive to at least 45 m. In UK coastal waters, dive times are typically around 20–45 seconds, with a recovery time of around 15 seconds between dives; this is consistent with aerobic diving, i.e. the bird depends on the oxygen in its lungs and dissolved in its bloodstream during the dive. When they dive, they jump out of the water first to give extra impetus to the dive.

There are three subspecies:

  • Phalacrocorax aristotelis aristotelis - northwestern Europe (Atlantic Ocean coasts)
  • Phalacrocorax aristotelis desmarestii - southern Europe, southwest Asia (Mediterranean Sea and Black Sea coasts)
  • Phalacrocorax aristotelis riggenbachi - northwest African coast

The subspecies differ slightly in bill size and the breast and leg color of young birds. Recent evidence suggests that birds on the Atlantic coast of southwest Europe are distinct from all three, and may be an as-yet undescribed subspecies.

Found in Songbird ReMix Seabirds Volume 2

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