Peruvian tern (Sterna lorata)
|Size||Size: 22 – 24 cm (2)|
Classified as Endangered (EN) on the IUCN Red List 2006 (1).
The Peruvian tern is one of the rarest seabirds in the world (3). This small, typical-looking tern has a snowy white forehead, throat and chin, and a contrasting black cap, from which a distinctive black stripe extends through the eye to the beak (2) (4). In non-breeding adults, the black crown is streaked with white. The rest of the plumage is primarily pale grey, slightly paler on underparts, and the legs and bill are yellow, with the bill being conspicuously tipped in black (2). Eggs and chicks are strongly camouflaged against the sandy substrate of their beach nest, being pale grey to beige, both finely spotted with dark brown to black (2) (4).
Recorded from Central Ecuador to North Chile along the western coast of South America (2) (5). There are now only three or four current breeding sites known in Peru and three in Chile (5).
This coastal bird breeds on broad sandy beaches and sand dunes, often more than 1,000 m from the tide line, as well as on barren stony desert several kilometres inland (2).
Breeding is thought to extend from October through to January, peaking in November, with full-grown juveniles observed by mid-February. Peruvian terns are solitary to semi-colonial, usually nesting more than 50 m apart in sparse colonies of 2 to 15 pairs (2). Nests are scrapes in the sand without any additional nest material, into which one to two eggs are laid (2) (3). Eggs are incubated for 22 to 23 days (2), and the cryptic colouration of both the eggs and emerging chicks helps hide them from potential predators, such as the peregrine falcon (Falco peregrinus), grey fox (Dusicyon culpaeus) and skunk (Conepaetus rex) (2) (3). Even so, many eggs do not hatch and usually only one chick is raised (2).
The diet mainly includes small fish, particularly anchovetta (Engraulis ringens) and krill (Euphausia). Like several other terns, this bird often feeds by hovering over water and then plunge-diving to snatch its prey (2).
The Peruvian tern’s small population is largely threatened by disturbance and loss of its breeding grounds due to human development, frequently the building of shanty towns and summer homes, and as the result of human activities such as 4x4 vehicle driving on the beaches. Off-road vehicles have also led to increased access, and therefore disturbance, to previously inaccessible breeding areas. In Chile, current concerns include the building of port facilities at Mejillones, off-road driving at Rio Loa and the construction of coastal highways throughout the north. In Paracas Bay, Peru, increased pollution may also pose a risk to the birds (5). Furthermore, with greater development and human encroachment on the Peruvian tern’s breeding habitat comes a greater threat from domestic animals such as dogs and cats, which may disturb, prey or trample upon eggs and young chicks (3). This already rare bird has also undoubtedly suffered from the 1972 collapse of anchovetta stocks, an important food source, which have not subsequently recovered (5).
There are currently no known conservation measures underway to protect the Peruvian tern (5). Suggested measures include searching for colonies in previously unsurveyed areas and protecting known colonies from habitat disturbance and destruction, such as by building fences around breeding sites to prevent vehicle access (3).
For more information on the Peruvian tern see:
del Hoyo, J., Elliott, A. & Sargatal, J. (1996) Handbook of the Birds of the World - Hoatzin To Auks. Vol. 3. Lynx Edicions, Barcelona.
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Cryptic colouration: colouration that camouflages a species within its habitat.
IUCN Red List (May, 2006)
- del Hoyo, J., Elliott, A. and Sargatal, J. (1996) Handbook of the Birds of the World - Hoatzin To Auks. Vol. 3. Lynx Edicions, Barcelona.
University of North Carolina Wilmington (July, 2006)
Aves de Chile (July, 2006)
BirdLife International (July, 2006)