This striking bird occupies part of the same habitat ruled by the ancient Inca Empire in South America. Inca Terns are best known by their dashing white mustaches, which are found on both male and female birds.
The species is found only near the cold waters of the Humboldt Current, where the birds feed on anchovies and other small fish. Like Least Terns, Inca Terns feed by plunge diving and surface dipping. The birds also scavenge scraps from sea lions, dolphins, and fishing boats. Declining fish stocks are one of the reasons for this species’ population decline.
It’s a gregarious species, nesting in colonies of several thousand birds. This recording from Pantanos de Villa Wildlife Refuge outside of Lima, Peru, gives an idea of what these colonies are like.
The Inca Tern’s elaborate courtship includes a "high flight," with the male quickly ascending to several hundred feet, pursued by the female. Pairs choose a nest site in cliff hollows or fissures—sometimes even in the old nest burrow of a Humboldt Penguin. They often return to the same nest site for several years in a row, and both parents incubate and care for the chicks.
"Coastal Peru is a spectacular place to see vast numbers of Inca Terns and other seabirds such as Peruvian Boobies and Guanay Cormorants," said ABC Vice President Mike Parr. "It's hard to imagine that there were once even more seabirds using these waters. The double-whammy of over-fishing and excessive guano harvest—which eliminates nest sites—has been compounded by the effects of the El Niño cycle, which affects fish stocks."
Rats, cats, and other introduced predators on some islands also affect nesting and breeding success.
Following years of lobbying by in-country NGOs, the Peruvian government created the Guano Islands and Capes National Reserve in 2009, protecting Inca Tern as well as sea lion breeding colonies on 28 guano islands and cliffs along the coastline.