Guanay Cormorant vs Rock Shag

Guanay Cormorant

Leucocarbo bougainvilliorum

Huge2.5 kgMarine

The guanay cormorant is similar in plumage to the rock shag Leucocarbo magellanicus, but is larger, measuring 71–78 cm from the tip of the bill to the end of the tail, and has more extensive white on the underparts. The bill is grayish with some red at the base. The face is red with a green eye-ring. It has orange-pink feet. The head, neck and back are black, as are the outer parts of the thighs. The throat patch, breast and belly are white. In breeding plumage it has a few white feathers on the sides of the head and neck.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Aleks Clark from Ica, Peru · CC BY 2.0

Rock Shag

Leucocarbo magellanicus

Large1.5 kgMarine

At a distance, the rock shag is a black and white bird, with head, neck and upperparts black and chest and underparts white. Closer up, the black areas vary from metallic blue to oily green, and are flecked with white in places. The legs and feet are a pink, fleshy colour, and the bare flesh around the beak and eyes is brick red. In breeding condition, there is a blackish though not very prominent crest on the forehead, and a distinctive white ear patch. There is even less sexual dimorphism than in most cormorant species, but males are 5%-10% larger on most size measurements.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Arthur Chapman · CC BY 2.0

Photos and recordings are credited to their authors under the licence shown. Full profiles: Guanay Cormorant and Rock Shag.