Snowy-crowned Tern

Overview

The snowy-crowned tern, also known as Trudeau's tern, is a species of bird in the family Laridae. It is native to Argentina, Brazil, Chile, and Uruguay, with possible presence in Paraguay. Assessed as Least Concern by the IUCN, the species has a population estimated at below 6,700 mature individuals.

Identification

• Adults in breeding plumage feature a white head and neck with a distinct black band through the eye, pale gray upperparts, and a whitish rump.
• Measures 28 to 35 cm in length with a wingspan of 76 to 78 cm, possessing a blocky head, thick neck, long wings, and a forked tail.
• The bill is orange with a yellow tip and a black separating band in breeding adults, turning black with a yellowish tip in non-breeding plumage; legs are reddish orange.
• Vocalisation consists of a series of rapid notes like "je-je-je-je" or a short, grating "jeeer".

Habitat

This tern inhabits coastal and inland fresh and saline wetlands, with a preference for freshwater landscapes. It breeds from southeastern Brazil south through Uruguay to Buenos Aires Province in Argentina and in Chile between the provinces of Aconcagua and Llanquihue. Outside the breeding season, it ranges along the Atlantic coast as far north as the Rio de Janeiro area and on the Pacific coast to the Department of Ica in Peru.

Diet

The snowy-crowned tern feeds mostly on fish and occasionally on insects. It forages over shallow water along the edges of wetlands, rivers, lagoons, and plowed fields, taking fish by plunge-diving.

Did you know?

The species was named in honour of Dr. James de Berty Trudeau, who sent a specimen to John James Audubon, although the purported type locality of New Jersey is not supported by any documented North American records. It constructs floating platform nests in shallow water, often sharing nesting areas with brown-hooded gulls.