The Inca tern, scientifically known as Larosterna inca, is a bird species that is currently categorized as Near Threatened. Belonging to the subfamily Sterninae of the Laridae family, which includes gulls, terns, and skimmers, this unique bird can be spotted in various regions such as Chile, Ecuador, and Peru. Interestingly, there have been occasions where Inca terns have ventured as far as Central America and even Hawaii.
The Inca tern is a fascinating bird, measuring about 39 to 42 cm (15 to 17 in) in length and weighing around 180 to 210 g (6.3 to 7.4 oz). What sets this bird apart is its unique plumage. The adults have a predominantly dark slate gray body, with a slightly lighter throat and underwing coverts. You’ll notice a distinctive white stripe that starts from the base of their bill and extends along the side of their neck, forming long, silky feathers. The edges of their wings and the trailing edge of the four outer primaries also sport a crisp white color. Their forked tail is a sleek black. Their eyes have a brown hue, while their legs and feet are a deep shade of red. The bill of an Inca tern is dark red and has bare yellow skin at its base. When the young ones are born, they initially have a purplish brown hue that gradually transitions to a brownish gray as they mature into their adult plumage. Their bill and legs are initially a dark horn color, but over time, they acquire the striking red hue seen in adult Inca terns.
Distribution and natural environment:
The Inca tern is a fascinating avian species that primarily resides in the Humboldt Current area. Its breeding grounds stretch from Lobos de Tierra in the northern parts of Peru to the Aconcagua River near ValparaÃso, Chile. After the breeding season, some individuals migrate northwards and can be spotted in Ecuador. Although occasionally found in Panama and Costa Rica, it is considered a rare visitor in these regions. There have also been isolated sightings in Guatemala and Hawaii, suggesting its ability to travel long distances. However, it is important to note that the presence of the Inca tern in Colombia is yet to be officially documented and remains questionable, as it is treated as a hypothetical species by the South American Classification Committee of the American Ornithological Society.
The Inca tern can be found nesting in various locations, such as sea cliffs, guano islands, as well as man-made structures like ledges under piers and abandoned barges. Additionally, they will gather with other seabirds on sandy beaches.
In terms of feeding habits, the Inca tern primarily consumes small fish like anchoveta (Engraulis ringens). However, its diet also includes planktonic crustaceans and offal. They often gather in large flocks and can be seen near fishing boats or following other feeding animals like cormorants, sea lions, whales, and dolphins. These feeding flocks can contain up to 5000 birds. The Inca tern catches its prey by plunge-diving into the water, but it also has the ability to pick items from the surface while in flight or on the water.
Breeding Information:
The breeding habits of the Inca tern do not seem to be limited to any specific season. Eggs have been discovered between the months of April and July, as well as between October and December. Additionally, there have been observed signs of breeding in August. The Inca tern chooses diverse locations for nesting, such as fissures and caves found in rocky cliffs, among rocks and boulders on island slopes, inside abandoned burrows previously occupied by petrels and penguins, and even on or under man-made structures. Typically, the clutch of eggs consists of two, although occasionally only one. Both male and female Inca terns take turns in incubating the eggs and providing food for the young. The exact duration of the incubation period is unknown, but the fledglings usually leave the nest approximately four weeks after hatching. After fledging, the young Inca terns remain reliant on their parents for a minimum of one month.
Current Situation:
According to the IUCN, the Inca tern has been classified as Near Threatened. It inhabits a relatively limited area, and although the exact size of its population is uncertain, it is assumed to be declining. During El Niño events, the Inca tern experiences a substantial decline in reproductive success. Additionally, there are concerns regarding the potential impact of human hunting on its main food source, as well as the effects of climate change. In 2011, an approximate estimate suggested that the population of Inca terns stood at around 150,000 individuals.
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