Leucocarbo atriceps bransfieldensis (Murphy, 1936)

Size and Sexual Dimorphism

The imperial shag Leucocarbo atriceps bransfieldensis measures 70–79 cm (28–31 in) in total length and weighs 1.8–3.5 kg (4.0–7.7 lb), and males are typically larger than females.

Adult Breeding Plumage

Most of its body is covered in glossy black feathers, with a white belly and neck. 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 Adult Appearance

In the non-breeding season, adult imperial shags lose their crest, have duller-colored facial skin, and have less or no white coloring on their back and wings.

Bill Adaptation

Their bill is serrated, an adaptation used for catching fish.

Taxa Variation in Plumage

Different related taxa vary mainly in how much white coloring appears on the cheeks, ear-coverts, wing-coverts and back. While most taxa have white cheeks and ear-coverts, these areas are black in the taxa albiventer, purpurascens and melanogenis.

Chick Appearance

Chicks are a uniform brownish color.

Immature Bird Appearance

Immature birds are brownish and white (rather than black and white like adults), have dull facial skin, and lack the orange-yellow nasal knob and blue eye-ring.