Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Laridae
Genus: Larosterna
Species: Larosterna inca
In the world of birds, there are some species that captivate the imagination with their striking appearance and intriguing behaviours. Among these avian wonders is the Inca Tern (Larosterna inca), a charismatic seabird native to the coastal regions of South America. With its distinctively patterned plumage and remarkable aerial acrobatics, the Inca Tern stands out as a symbol of the rich biodiversity of its habitat.
Named after the ancient Inca civilization that once flourished along the western coast of South America, the Inca Tern is a sight to behold. Its most distinguishing feature is its striking black-and-white plumage, accented by a prominent red beak and webbed feet and narrow wattles of bright yellow skin below the birds’ white facial features. However, what truly sets the Inca Tern apart is its unique facial adornments. Both sexes have a bright white handlebar like moustache and look alike. Juveniles appear more brownish-purple and don’t grow their moustaches until they are about two years old. Scientists have learned that the length of the Inca Tern’s moustache indicates the health condition of the bird, meaning the longer the moustache the healthier the individual.
Inca terns are one of the larger species of Tern measuring approximately between 39-42 centimetres (15.35-16.53 inches) in length and a wingspan of around 80 centimetres (31.5 inches). This costal bird can weigh anywhere between 180-210 grams (6.35-7.41 ounces). Larosterna inca typically live up to or around 14 years old within the wild and have been known to live up to around 25 years old when in captivity.
These birds are primarily found along the Pacific coastline of South America, from northern Peru to central Chile. They are most spotted in coastal habitats such as rocky cliffs, sandy beaches, and offshore islands. These birds are well adapted to life by the sea, with strong wings that allow them to glide effortlessly over the ocean waves. These unique coastal birds typically do not migrate like other seabirds unless non-breading individuals have a lack of resources such as food.
Larosterna inca has a call that is described as a cat like meow or angry cat meow. This call can be loud and even louder when part of their large colony’s chorus and especially during courtship periods where these seabirds mark their territories and call to mates.
This species of Tern is what is known as piscivores meaning that they live on a diet of fish. Inca Terns are mostly known for eating anchovies but will also incorporate plankton, crustaceans such as shrimp, crabs and crayfish, and other species of fish into their diets. These seabirds are also kleptoparasites meaning that they will steal food from other animals such as dolphins and sea lions. Inca Terns have been known to steal food straight out of dolphin and sea lion mouths as well as steal fish from fishing boats.
One of the most impressive aspects of the Inca Tern's behaviour is its aerial prowess. These birds are skilled fliers, capable of executing intricate manoeuvres in mid-air with remarkable agility. During courtship displays, male Inca Terns engage in elaborate flight routines, soaring and diving in synchronized patterns to attract potential mates. These mesmerizing displays are a testament to the Inca Tern's grace and dexterity.
Inca Terns are highly social birds, often nesting in large colonies along coastal cliffs and rocky outcrops. This species of terns become sexually mature around 2-3 years old. During the breeding season, which typically occurs from September to March, these colonies become bustling hubs of activity as pairs of terns engage in courtship rituals and nest-building activities. Inca Terns are monogamous, forming long-term pair bonds with their mates with some pairs even breeding for life. Once these birds have mated, the female of the pair will typically lay a clutch between 1-3 eggs, which are either tan or light brown in colour and feature dark brown spots. They lay their eggs between April-July or October-December and have an incubation period of around 3-4 weeks, of which both parents take it in turns to incubate the eggs. Once the egg/s have hatched both parents of the offspring work together to feed and raise their young until they are ready to fledge at around seven weeks old.
Despite their striking appearance and fascinating behaviour, the Inca Tern faces several threats to their survival and have been listed as Near Threatened (NT) by the IUCN with their numbers decreasing. There were once millions of these unique looking seabirds but now there are only around 150,000 in the wild.
Habitat loss, pollution, and disturbance at breeding sites are among the primary challenges confronting these birds. Additionally, fluctuations in food availability due to climate change and overfishing (primarily anchovies) caused by humans can impact the Inca Tern's ability to thrive. Predators such as cats, rats, sea lions, raptors/birds of prey and larger seabirds are also declining the Inca Tern’s numbers as natural predators of both adults, chicks, and eggs. Inca Tern populations are also at stake due to humans excessively harvesting the Inca Tern guano (excrement) which is used as a favourite fertilizer, in turn destroying their habitats. However, the Peruvian government has put in place conservation efforts by establishing a reserve to protect Inca Terns and other seabirds from this excessive guano harvesting. By raising awareness about the importance of preserving coastal ecosystems and implementing measures to reduce human impact on nesting sites, conservationists are working to secure a brighter future for these magnificent seabirds.
Inca Terns are truly remarkable creatures, embodying the beauty and diversity of South America's coastal regions. With their striking appearance, impressive aerial abilities, and complex social dynamics, these birds have captured the hearts of birdwatchers and nature enthusiasts around the world. As stewards of our planet's biodiversity, it is our responsibility to safeguard the habitats upon which species like the Inca Tern depend. By working together to protect these invaluable ecosystems, we can ensure that future generations of this jewel of the South American coastline will continue to marvel at the splendour of this enigmatic avian species.
Photograph of Inca Tern by Ella Munro at Bristol Zoo
Map and IUCN listing graphics by Ella Munro
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