About Leucocarbo atriceps (King, 1828)
Scientific Name and Size
The imperial shag, scientifically named Leucocarbo atriceps (King, 1828), measures 70–79 cm (28–31 in) in total length and weighs 1.8–3.5 kg (4.0–7.7 lb), with males typically larger than females.
Plumage Coloration
Most of its body is covered in glossy black feathers, while its belly and neck are white.
Distinctive Facial and Body Features
It has a distinctive ring of blue skin surrounding its eyes, an orange-yellow nasal knob, pinkish legs and feet, and an erectile black crest.
Non-breeding Season Appearance
In the non-breeding season, adult imperial shags lose their crest, have duller facial skin, and show less or no white coloring on their back and wings.
Bill Adaptation
The species has a serrated bill adapted for catching fish.
Population Morphological Differences
Populations of this group primarily differ in how much white appears on the cheeks, ear-coverts, wing-coverts, and back.
Subspecific Plumage Variation
Most taxonomic groups within this species have white cheeks and ear-coverts, but these areas are black in the albiventer, purpurascens, and melanogenis variants.
Juvenile and Immature Appearance
Chicks are uniformly brownish, while immature individuals are brownish and white (rather than black and white), have dull facial skin, and lack both the orange-yellow nasal knob and blue eye-ring.
