copyright: Don DesJardin
Sterna elegans, the Elegant Tern, is a medium-size, orange-billed, shaggy-crested member of the tern subfamily. It is very similar in appearance to the Royal Tern, but is smaller and more slender, with a much thinner, proportionately longer, slightly decurved orange or orange-yellow bill. Its tail is moderately forked.
In summer, the Elegant Tern has a black cap with a long crest that extends from the top of the bill to the back of the head. In winter, the plumage on the head changes. The forehead is white, the crown gray, and the black nape extends forward to the eyes.
This species breeds on flat rocky areas and is strongly tied to the coast. It forages in inshore waters, estuarine habitats, salt ponds and lagoons, with some individuals venturing further offshore in the non-breeding season.
Sterna elegans breeds along the Pacific coast from south California, USA, to Baja California and the Gulf of California, Mexico. The estimated population is 51,000-90,000 individuals with up to 95% breeding on Isla Rasa in the Gulf of California. At least three other Mexican islands are used at least occasionally. In addition, small populations breed on Bolsa Chica (50-4,000 pairs, first recorded in 1987) and in San Diego bay (500-800 pairs), California. Non-breeding birds summer from California to Costa Rica. Birds winter from Guatemala to El Salvador, Nicaragua, Costa Rica, Panama, Colombia, Ecuador, Peru and Chile. There are significant population fluctuations, probably caused by the effects of El Niño Southern Oscillation (compounded by over-fishing) on prey abundance and consequently breeding success. Only the Isla Rasa colony breeds every year, but fluctuations are considerably less than one order of magnitude.
Surprisingly, this Pacific species has wandered to western Europe as a rare vagrant on a number of occasions, and has interbred with the Sandwich Tern in France; there is also one record from Cape Town, South Africa in January 2006, the first record for Africa.
They eat primarily small fish, which they catch by diving from the the air.
The Elegant Tern feeds by plunge-diving for fish, almost invariably from the sea, like most Thalasseus terns. It usually dives directly, and not from the “stepped-hover” favoured by the Arctic Tern. The offering of fish by the male to the female is part of the courtship display.
This species is considered Near Threatened as it has a restricted breeding range, with more than 90% of the breeding population being restricted to a single island. It is also subject to large population fluctuations in response to climatic effects, and could be negatively affected by climate change, human intrusions and overfishing. [conservation status from birdlife.org]
They breed on the coasts and islands of Mexico and Central America, placing their eggs on the sand. They are believed to lay but a single egg, like that of the Royal Tern, but smaller. Size 2.40 x 1.40. Terns are gregarious birds and breed colonially. The Elegant Tern nests only in a scrape in the sand; other species, like the Forster’s and Black Terns, build a substantial nest of vegetation. One to two pinkish eggs are laid, and incubation lasts about 20 days.
Post-breeding dispersal northward to N California and rarely to British Columbia. Uncommon migrant off Pacific coast of Costa Rica. Winters on Pacific coast from Guatemala to C Chile, mostly in Peru and N Chile. Accidental in Texas. Odd records from Netherlands, Ireland, Spain and France (including hybridization with T. sandvicensis), but provenance of such birds in question, as species virtually unrecorded anywhere in North America away from Pacific coast; probably attributable to escapes from shipments of exotic seabirds from wintering grounds in W South America.
- spanwidth min.: cm
- spanwidth max.: cm
- size min.: 39 cm
- size max.: 43 cm
- incubation min.: 20 days
- incubation max.: 21 days
- fledging min.: 0 days
- fledging max.: 0 days
- broods 1
- eggs min.: 1
- eggs max.: 2
- Conservation Status