Guanay Cormorant, Phalacrocorax bougainvillii

The Guanay Cormorant (Phalacrocorax bougainvillii ), also known as the Guanay Shag, is part of the cormorant family, and it usually resides on the Pacific coast of Peru and northern Chile, however, the Argentinean population on the Patagonian Atlantic coast seems to be extinct. The major habitats of this bird appear to be shallow seawater and rocky shores.

This bird’s color is similar to the Rock Cormorant. It has a grayish bill with some red around the base and the face is red with a green eye-ring. It has pink feet, and the head, neck, back and outer thighs are black. The throat, breast and belly are white and in the breeding plumage it has a few white feathers on the sides of the head and neck. The cormorant measures 78 cm from bill to tail.

Breeding normally happens year round, peaking in November and December. In high density colonies, there are up to three nests per square meter. These nests are made of guano on flat surfaces either on offshore islands or remote headlands. The cormorant lays two to three eggs, approximately 63×40 mm in size.

After breeding, the birds migrate south to southern parts of Chile and north to Ecuador, and have also been recorded as far north as Panama and Columbia. This is most likely a result of mass dispersal because of food shortages during El Nino years.

This bird feeds mostly on the Peruvian anchoveta and Peruvian silverside () which thrive in the cold Humboldt Current. The Guanay Cormorant is the main producer of guano.

Over-fishing, Habitat loss, and degradation have resulted in a steady decrease of population of about 30% from an estimated number of 3 million birds in 1984. The species is listed as near threatened by the IUCN. The scientific name memorializes the French explorer Louis Antoine de Bougainville.

Image Caption: Guanay Cormorant (Phalacrocorax bougainvillii) in the Walsrode Bird Park, Germany. Credit: Quartl/Wikipedia (CC BY-SA 3.0)