Inca Terns are an extremely social bird, living and resting in huge colonies of up to several thousand birds. They are striking due to their blue-grey plumage, red beaks, and unusual white moustaches. They will breed twice a year, with the males performing agile flight displays to impress females. Males will also take part in courtship feeding, following a female in the air with a fish in his beak. Once a male and female have paired, they pick a nesting site, normally in crevices and abandoned burrows. They can also nest in abandoned buildings. They are near threatened, and appear to have suffered a severe population drop relatively recently due to a large El Niño storm that caused fish to flee to cooler areas.