The Inca Tern (Larosterna inca) is easily recognisable with its bright bill and facial plume feathers. The individuals here were photographed at Torquay's Coastal Zoo and Aquarium (Living Coasts) in the UK.
HABITAT AND DISTRIBUTION
The preferred habitat of the Inca tern is along the Pacific coast of Peru and Chile where it favours cliffs. It does frequent parts of Ecuador as a guest. It is endemic to the area known as the Humboldt Current and will also nest on rocky islands, however domestic introduced species such as cats and rats may prohibit nesting.
The overall colour of the Inca tern is a dark grey, with bright orange-red feet and bill. The face exhibits long white plumes next to yellow bare facial skin (wattles near the base of the bill known as the gape) and the crown is grey-black. The long plumes denote health, the longer they are the healthier the specimen. The tail is a darker grey and separated from the wings by the pale trailing edge when at rest. Juveniles are a brown-grey colour, lack the colourful facial plumes and skin, and have dark legs and bill. It reaches an overall length of about 40cm and can weigh 180 - 210g.
DIET, BEHAVIOUR AND REPRODUCTION
The diet consists of crustaceans and small fish including Peruvian Anchoveta (Engraulis ringens), Mote Sculpins (Normanichthys crokeri) and Peruvian Silversides (Odontesthes regia). The Inca tern is also known to take scraps from large mammals such as sea-lions and dolphins. When hunting the Inca tern will hover over water at a height, before plunge diving to catch its prey. Once a mating pair has established themselves, mating will occur twice a year; once in spring and once in winter. The Inca tern lays 1 - 2 eggs in a burrow, cave or cavity. It has been reported that it also reuses the old nests of Humboldt Penguins (Spheniscus humboldti). Courtship may include head bobbing, vocal calls and feeding, and in captivity same sex pairs have been observed.
OTHER NOTABLE INFORMATION
The Inca Tern is the sole member of the genus Larosterna. The Inca tern is named after its range, it inhabits roughly the same area that was once ruled by the Inca tribes.
The Inca tern is listed by the IUCN as Near Threatened, this is largely due to its slow decline. Plausible reasons would be the guano trade (sea bird manure) and reduction of their sea fish foods. The population once thought to be in the millions has been reduced to around 150,000.