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Showing posts with label INCA TERN (MALE) (Larosterna inca). Show all posts
Showing posts with label INCA TERN (MALE) (Larosterna inca). Show all posts

Thursday, 17 July 2025

15-7-2025 AMSTERDAM ZOO, HOLLAND - INCA TERN (MALE) (Larosterna inca)

The Inca tern (Larosterna inca) is a near-threatened species of tern in the subfamily Sterninae of the family Laridae (the gulls, terns, and skimmers). It is found along the Pacific coasts of Chile, Ecuador and Perú, and has appeared as a vagrant in Central America and Hawaii.

The Inca tern is roughly 39 to 42 cm (15 to 17 in) long and weighs between 180 to 210 g (6.3 to 7.4 oz). Its plumage is uniquely colored among terns; adults have a mostly dark, slate-gray body, with paler underwing coverts, and a slightly paler throat. A white stripe extends back from the base of the bill and fans out like a Salvador Dalíesque mustache as long, satiny feathers along the side of the neck. The trailing edge of the wing (the tips of the secondaries and the three inner primaries) are white. The tail is black, and moderately forked. The iris is brown, with legs and feet that are dark red. The bill is bright to dark red, with bare yellow skin at the base. The chicks, on hatching, are purplish-brown, progressing through brownish-gray before developing mature plumage. The chicks' bills and legs are dark and horn-colored, and gradually attain the red that adults have.

The Inca tern is an inhabitant of the Humboldt Current region. It breeds from Lobos de Tierra, in northern Perú, south to the Aconcagua River, near Valparaíso, Chile. Some disperse north into Ecuador after breeding, and south to the Puerto Montt area of Chile, where multiple 'research-grade' sightings with photos on the biodiversity database iNaturalist, including a group of four together. It is a casual visitor to Panamá and Costa Rica, and has also been recorded as a vagrant in Guatemala and Hawaii. The documented Hawaiian birds, in particular, remained from March through November on the Hawaiian archipelago.

The South American Classification Committee of the American Ornithological Society treats the Inca tern's presence in Colombia as "hypothetical", due to a number of unverified or undocumented sightings. On iNaturalist, one 'research-grade' sighting (with photo) has been documented from the coast of Buenaventura, Colombia's Isla Cascajal, dated July 2023; however, the species' popularity in captivity (see Captivity below) complicates assessment of extralimital records.

The Inca tern nests on sea cliffs and guano islands, as well as manmade structures (such as ledges under piers) and abandoned barges. It will gather with other sea and shorebirds on sandy beaches.

Large flocks may occur where conditions are suitable, as here on the Islas Ballestas off the Peruvian coast

The Inca tern is essentially non-migratory, although some disperse northwards after breeding. Some rogue individuals have flown great distances.

The Inca tern feeds primarily on small fish, such as anchoveta (Engraulis ringens), and also consumes planktonic crustaceans and offal or carrion in its diet. Large flocks congregate around fishing boats and will also follow the feeding patterns of cormorants, sea lions, and whales and dolphins. Feeding flocks can number over 5,000 birds. The Inca tern catches its prey mainly by plunge-diving, but also picks items from the surface while flying or floating on the water.

Breeding does not appear to be concentrated in any season. Eggs have been found between April and July and between October and December, and other evidence of breeding has been noted in August. It nests in a variety of sites including fissures and caves in rock cliffs, among rocks and boulders on island slopes, in abandoned petrel and penguin burrows, and on and under human structures. The clutch size is usually two eggs though sometimes one. Both sexes incubate the clutch and provision the young. The incubation period is not known; fledging occurs about four weeks after hatch and the young are fully dependent on the adults for at least a month after fledging.

The Inca tern is most vocal at its nesting colonies. Its calls include "raucous cackling notes" and "mewing"; the latter call has been likened to that of a kitten.

The IUCN has assessed the Inca tern as Near Threatened. It has a somewhat restricted range; its population size is not known and is believed to be decreasing. "Reproductive success is dramatically reduced during El Niño events". Human harvesting of its primary prey is a probable threat as is climate change. One estimate placed its population at about 150,000 in 2011.7.

Sunday, 18 March 2018

14-8-2017 AMSTERDAM ZOO, NETHERLANDS - INCA TERN (MALE) (Larosterna inca)


The Inca tern is one of the world’s most beautiful and interesting birds. It occurs along the Pacific Coast from northern Peru to central Chile. This bird is easily recognizable with its dark gray body, and red-orange beak and claws, and its lovely white moustache. It is an adept flier that swoops and hovers before it dives after its prey. It sometimes plucks pieces of fish out from between sea lions’ teeth. Unfortunately, their populations are declining quickly because of the loss of nesting sites. They have been included in the “close to vanishing species” category. Inca terns in the wild live up to 14 years and in captivity up to 20 years.


The Inca tern is a large tern, approximately 40 cm (16 in) long. Sexes are similar; the adult is mostly slate-grey with white restricted to the facial plumes and the trailing edges of the wings. The large bill and legs are dark red. Immature birds are purple-brown, and gradually develop the facial plumes.

The Inca tern is a diurnal, gregarious species, living and nesting in large colonies numbering several thousand birds, often close to gull colonies. Inca terns follow fishing boats and often associate with whales and sea lions when feeding, stealing food from these fellow marine mammals. Inca terns feed by plunge-diving from a height, after a brief flight above their prey, or by surface-dipping, whereby they swim or sit on the water and pick up prey from the surface. They are not strong swimmers, as their webbed feet are not big enough. Inca terns remain resident within their range, though non-breeding birds sometimes move, depending on food resources.

Monday, 14 August 2017

14-8-2017 AMSTERDAM ZOO, NETHERLANDS - INCA TERN (MALE) (Larosterna inca)


The Inca tern is one of the world’s most beautiful and interesting birds. It occurs along the Pacific Coast from northern Peru to central Chile. This bird is easily recognizable with its dark gray body, and red-orange beak and claws, and its lovely white moustache. It is an adept flier that swoops and hovers before it dives after its prey. It sometimes plucks pieces of fish out from between sea lions’ teeth. Unfortunately, their populations are declining quickly because of the loss of nesting sites. They have been included in the “close to vanishing species” category. Inca terns in the wild live up to 14 years and in captivity up to 20 years.

The Inca tern is a large tern, approximately 40 cm (16 in) long. Sexes are similar; the adult is mostly slate-grey with white restricted to the facial plumes and the trailing edges of the wings. The large bill and legs are dark red. Immature birds are purple-brown, and gradually develop the facial plumes.


The Inca tern is a diurnal, gregarious species, living and nesting in large colonies numbering several thousand birds, often close to gull colonies. Inca terns follow fishing boats and often associate with whales and sea lions when feeding, stealing food from these fellow marine mammals. Inca terns feed by plunge-diving from a height, after a brief flight above their prey, or by surface-dipping, whereby they swim or sit on the water and pick up prey from the surface. They are not strong swimmers, as their webbed feet are not big enough. Inca terns remain resident within their range, though non-breeding birds sometimes move, depending on food resources.


Inca terns are monogamous, pairs often returning to the same nesting site year on year. Courtship consists of an elaborate ritual, particularly for birds seeking their mate for the very first time. Males perform an agile flight display to impress their chosen female. They also perform courtship feeding while following the female while flying, with a fish in their bill. This species breeds twice a year, firstly between April and July, secondly between October and December. Nests are on guano islands or sandy beaches and they choose deep rock crevices where there are many cavities and cliffs that offer good protection. Chicks hatching in deep holes are given protection for longer from predators, whereas nests that are further from cliffs are more accessible to raptors and large seabirds. 1-3 eggs are laid and incubation lasts for about 3-4 weeks. The parents both incubate and feed the chicks. The young are grayish in color and fledge at about 4 weeks old. They reach their independence one month later and will be ready to breed at age 2 or 3.


Inca tern numbers are affected by food resources, as well as El Niño and other strong storms. Populations decline during such severe storms, though they fairly quickly become stable again. The biggest threat currently is over-fishing, as this reduces the fish available for the terns to eat. Production of guano can also reduce the number of nesting sites available, and cats and rats may eat eggs and chicks.

According to the IUCN Red List, the total Inca tern population size is more than 150,000 individuals. Currently this species is classified as Near Threatened (NT) and their numbers today are decreasing.