Inca tern

The inca tern is one of South America’s most striking coastal birds, with its bright red beak and curved, snow-white cheek feathers that protrude from its face like a curled moustache. However, these distinctive features of its appearance only develop as the bird grows older: as juveniles, inca terns have brown plumage – without a red beak or a moustache.

The length of the white moustache appears to be linked to the animals’ state of health. A study suggests that birds with particularly long moustaches are, on average, in better physical condition and raise heavier chicks with a better-developed immune system.

Inca terns typically breed in large colonies. They lay their eggs in sheltered cavities – for example, in guano (weathered layers of bird droppings), in the ground or in rock crevices. However, they also make use of abandoned nesting cavities of other seabirds, such as the Humboldt penguin, with which they coexist in this region. 

The inca tern catches fish by diving deep from the air or by what is known as ‘dipping’, in which it dives just below the water’s surface without submerging completely. Furthermore, the species displays distinctly opportunistic behaviour: Inca terns frequently follow fishing boats, seals, whales or cormorants in order to feed on fish that have been flushed out or on fish scraps. It is not uncommon for them to steal pieces of fish directly from boats or even from the mouths of surfacing sea lions. 

The Peruvian anchovy is the inca tern’s main prey and is also one of the most intensively fished species in the world. Continued overfishing could have a negative impact on the inca tern’s breeding success in the long term.

The effects of the so-called El Niño events are also particularly serious: changes in ocean currents and rising water temperatures are causing a sharp decline in plankton – the main food source for anchovies. As a result, the schools of fish on which the inca tern feeds are also absent.