Phalacrocoracidae – Cormorants & Shags

Flightless Cormorant Phalacrocorax harrisi ©Sam Woods Website

The Phalacrocoracidae is a family of some 41 species of aquatic birds commonly known as cormorants or shags. Several different classifications of the family have been proposed recently, and the number of genera is disputed. There is no consistent distinction between cormorants and shags as these appellations have been assigned to different species seemingly randomly.

They are medium-to-large seabirds. They range in size from the Pygmy Cormorant Phalacrocorax pygmaeus, at as little as 45cm and 340g, to the Flightless Cormorant Phalacrocorax harrisi, at a maximum size 100cm and 5kg. The recently extinct Spectacled Cormorant Phalacrocorax perspicillatus was rather larger, at an average size of 6.3kg. The majority, including nearly all Northern Hemisphere species, have mainly dark plumage, but some Southern Hemisphere species are black and white, and a few (e.g. the Spotted Shag of New Zealand) are quite colourful. Many species have areas of coloured skin on the face (the lores and the gular skin) which can be bright blue, orange, red or yellow, typically becoming more brightly coloured in the breeding season. The bill is long, thin, and sharply hooked. Their feet have webbing between all four toes, as in their relatives.

They are coastal rather than oceanic birds, and some have colonised inland waters – indeed, the original ancestor of cormorants seems to have been a fresh-water bird, judging from the habitat of the most ancient lineage. They range around the world, except for the central Pacific islands.

All are fish-eaters, taking small eels, other fish, and even water snakes. They dive from the surface, though many species make a characteristic half-jump as they dive, presumably to give themselves a more streamlined entry into the water. Under water they propel themselves with their feet, though some also propel themselves with their wings. Some cormorant species have been found to dive to depths of as much as 45 metres.

After fishing, cormorants go ashore, and are frequently seen holding their wings out in the sun. All cormorants have preen gland secretions that are used ostensibly to keep the feathers waterproof. Some sources state that cormorants have waterproof feathers while others say that they have water permeable feathers. Still others suggests that the outer plumage absorbs water but does not permit it to penetrate the layer of air next to the skin. The wing drying action is seen even in the flightless cormorant but commonly in the Antarctic Shag and Red-legged Cormorant. Alternate functions suggested for the spread-wing posture include that it aids thermoregulation, digestion, balances the bird or indicates presence of fish. A detailed study of the great cormorant concludes that it is, without doubt, to dry the plumage.

Cormorants are colonial nesters, using trees, rocky islets, or cliffs. The eggs are a chalky-blue colour. There is usually one brood a year. The young are fed through regurgitation. They typically have deep, ungainly bills, showing a greater resemblance to those of the pelicans, to which they are related, than is obvious in the adults.

According to the IOC there are 41 extant species of Cormorants & Shags in the family Phalacrocoracidae; they are:

Little Pied Cormorant Microcarbo melanoleucos
Reed Cormorant Microcarbo africanus
Crowned Cormorant Microcarbo coronatus
Little Cormorant Microcarbo niger
Pygmy Cormorant Microcarbo pygmeus

Red-legged Cormorant Phalacrocorax gaimardi
Flightless Cormorant Phalacrocorax harrisi
Bank Cormorant Phalacrocorax neglectus
Spotted Shag Phalacrocorax punctatus
Pitt Shag Phalacrocorax featherstoni
Pallas’s Cormorant Phalacrocorax perspicillatus
Brandt’s Cormorant Phalacrocorax penicillatus
Pelagic Cormorant Phalacrocorax pelagicus
Red-faced Cormorant Phalacrocorax urile
Neotropic Cormorant Phalacrocorax brasilianus
Double-crested Cormorant Phalacrocorax auritus
European Shag Phalacrocorax aristotelis
Black-faced Cormorant Phalacrocorax fuscescens
Indian Cormorant Phalacrocorax fuscicollis
Little Black Cormorant Phalacrocorax sulcirostris
Australian Pied Cormorant Phalacrocorax varius
Great Cormorant Phalacrocorax carbo
White-breasted Cormorant Phalacrocorax lucidus
Japanese Cormorant Phalacrocorax capillatus
Cape Cormorant Phalacrocorax capensis
Socotra Cormorant Phalacrocorax nigrogularis
Rock Shag Phalacrocorax magellanicus

Guanay Cormorant Leucocarbo bougainvillii
Imperial Shag Leucocarbo atriceps
South Georgia Shag Leucocarbo georgianus
Antarctic Shag Leucocarbo bransfieldensis
Heard Island Shag Leucocarbo nivalis
Crozet Shag Leucocarbo melanogenis
Macquarie Shag Leucocarbo purpurascens
Kerguelen Shag Leucocarbo verrucosus
New Zealand King Shag Leucocarbo carunculatus
Otago Shag Leucocarbo chalconotus
Foveaux Shag Leucocarbo stewarti
Chatham Shag Leucocarbo onslowi
Campbell Shag Leucocarbo campbelli
Auckland Shag Leucocarbo colensoi
Bounty Shag Leucocarbo ranfurlyi

Number of Species
  • Number of bird species: 41

Useful Reading
  • Flight Identification of European Seabirds

    by Anders Blomdahl, Bertil Breife & Niklas Holmstrom from Christopher Helm April 2003 Price £35. See Fatbirder Review ISBN: 0713660201 Buy this book from NHBS.com
  • Pelicans, Cormorants and their Relatives - The Pelicaniformes

    by J Bryan Nelson, illustrated by John Busby, Andrew Mackay and Bas Teunis OUP 2005
    See Fatbirder Review ISBN: 0198577273 Buy this book from NHBS.com
  • Seabirds

    by Peter Harrison - Helm 1985 ISBN: 071363510X Buy this book from NHBS.com
Organisations
  • Cormorants - All about Phalacrocoracidae & related taxa

    Website
    The official Internet website of the Wetlands International Cormorant Research Group
  • Cormorants Research Group

    Website
Other Links
  • Flight Identification of European Seabirds

    Website
    Seawatching has been gaining popularity in recent years, whether watching from traditional coastal sites or from boats while on specific pelagic trips in search of seabirds and whales. Many seabirds will only be seen in flight, as they pass by prominent headlands or fly past boats, and viewing opportunities are frequently brief. This forthcoming book is the essential field guide for seawatching, specifically designed to address the particular problems and limitations with this kind of birding.

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