Shags

Although most Shags and Cormorants are (still) placed in Phalacrocorax (Nelson, 2005) the group as whole can be divided into two subgroups: the Shags and the Cormorants and these in their turn are divided into two ore more genera and groups by various authors. This division is based on ecological, behavioral and physiological characteristics (Johnsgard, 1993) and more recently on the studies of Siegel-Causey (1988) and Kennedy et al. (2000). More about taxonomy
Shags are typical found in coastal waters.
This page treats the ‘true’ Shags of the genera Phalacrocorax and Leucocarbo.

Osteology

All Cormorants, Shags and Darters have a small bone at the back of the skull, the occipital style. This bone is flexibly attached to the skull and is supposed to have a function for the grasping ability of these birds. The ramphotecal coating of the  bills of the cormorants are divided in plates, very much like those of the tubenoses, without visible nostrils. See also the osteology page.

Cliff Shags

Genus Phalacrocorax

  • Socotra Shag Phalacrocorax nigrogularis, Persian Gulf, south-eastern coast Arabian peninsula and adjacent islands.
  • European Shag Phalacrocorax aristoteles, three subspecies:
    - P. a. aristoteles, northern European Atlantic coasts to Iberian Peninsula
    - P. a. desmarestii, Mediterranean coasts
    - P. a. riggenbachi, Atlantic coast of Morocco
  • Rock Shag Phalacrocorax magellanicus, coast of South America from Santiago de Chile to Uruguay and Falkland Is.

Marine Cormorants

Genus Phalacrocorax

  • Red-Legged Cormorant or Red-legged Shag Phalacrocorax gaimardi, Pacific coast of South America and southernmost Argentina.
  • Brandt’s Cormorant Phalacrocorax pencillatus, North American west coast from Baja California up to British Columbia.
  • Pelagic Cormorant or Pelagic Shag Phalacrocorax pelagicus, from Baja California to Japan and Korea.
  • Red-faced Cormorant or Red-faced ShagPhalacrocorax urile, from Hokkaido, Japan to Alaska.

Brandt’s Cormorant
Phalacrocorax pencillatus

Florence, OR, USA
Culmen: 70.0 mm,
Total: 142,2 mm (ex. occ. style) Unsexed adult

Pelagic Shag
Phalacrocorax pelagicus
Location unknown
Culmen: ca 47 mm,
Total : 101,8 (ex. occ. style)
Unsexed adult

European Shag
Phalacrocorax a. aristoteles
Tramore Ireland
Culmen: 57.0 mm,
Total 119.6 mm (ex. occ. style)
Unsexed adult

Socotra Shag
Phalacrocorax nigrogularis

Bahrein
Total: 132 mm (occipital style missing)
Unsexed adult

Spotted Shags

  • Spotted Shag Phalacrocorax  punctatus, New Zealand.
  • Pitt (Island) Shag Phalacrocorax featherstoni, endemic to the Chatham Is.

Spotted Shag
Phalacrocorax punctatus
Taiaroa Head, SI, New Zealand
Culmen: 58.9 mm;
Total: 128.3 mm (ex. occ. style)
Unsexed adult

Blue-eyed Shags

Genus Leucocarbo

A group of complex taxonomy is formed by the so-called Blue-eyed Shags (a misnomer because not all of them have blue eyelids) and the New Zealand Blue-eyed Shags. Formerly considerered to contain about eight subspecies of the Imperial Shag Leucocarbo atriceps and subspecies of the Rough-faced Shag Leucocarbo caruncluatus, but now split into a range of separate species and proposed species. The Guanay Shag Leucocarbo bougainvillii seems to be a northern representative of the the Blue-eyed Shags (Kennedy et al. 2000)

  • Guanay Shag or Guanay Cormorant Leucocarbo bougainvillii. Pacific coast of South America
  • Imperial Shag Leucocarbo atriceps. Tierra del Fuego
  • King or Falkland Blue-eyed Shag Leucocarbo albiventer. Endemic to Falkland Is.
  • Kerguelen Shag Leucocarbo verrucosis. Endemic to Kerguelen Is.
  • Rough-faced Shag Leucocarbo carunculatus. Endemic to New Zealand, Marlborough Sound.
  • Bronze or Stewart Island Shag Leucocarbo chalconotus. Endemic to New Zealand, Stewart I. and southern coast of South Island.
  • Chatham (Island) Shag Leucocarbo onslowi. Endemic to Chatham Is.
  • Campbell (Island) Shag Leucocarbo campbelli. Endemic to Campbell Is.
  • Auckland (Island) Shag Leucocarbo colensoi. Endemic to Auckland Is.
  • Bounty (Island) Shag Leucocarbo ranfurlyi. Endemic to Bounty Is
  • Antarctic Blue-eyed Shag Leucocarbo bransfieldensis (proposed split). Antarctic peninsula and Antarctic Archipelago.
  • (South) Georgian Shag Leucocarbo georgianus (proposed split). South Georgia I.
  • Crozet Shag Leucocarbo melanogenis (proposed split). Endemic to Prince Edward, Marion and Crozet Is
  • Heard Shag Leucocarbo nivalis (proposed split). Endemic to Heard I.
  • Maquarie (Island) Shag Leucocarbo purpurascens (proposed split). Endemic to Maquarie I.

Stewart Island Shag
Leucocarbo
chalconotus
Taiaroa Head, SI, New Zealand
Culmen: 61.6 mm;
Total : 136.9 mm (ex. occ. style)
Adult male.

References