Tern Thalasseus Research Articles

Provisioning of mates and chicks by Cayenne and Royal Terns: resource partitioning in northern Patagonia, Argentina

Cayenne (Thalasseus sandvicensis eurygnathus) and Royal Terns (Thalasseus maximus) breed in mixed colonies in Argentina. This paper presents the first detailed information on their breeding diet and assesses differences and overlap between species in the type and size of prey. During 2004 and 2005, observations of prey delivered to mates and chicks were carried out at Punta León, Patagonia. The diet of Cayenne and Royal Terns comprised nine and 10 prey species respectively. Fish comprised >99% of the prey of both species of tern in the two study years. Both species had a fairly specialised diet based on pelagic schooling fish, mostly Argentine Anchovy (Engraulis anchoita) and two species of silversides (Odontesthes spp.). Despite observed overlap in trophic resources, our results showed that Argentine Anchovy was the main prey for Royal Terns, whereas the two species of silversides together with Anchovy comprised the bulk of the diet for Cayenne Terns. Fish delivered by Cayenne Terns were significantly smaller than those by Royal Terns. Results suggested that both type and size of prey may be important factors permitting food partitioning between the two species of tern during the breeding season.

Interspecific Kleptoparasitism of Elegant Terns by Snowy Egrets

Abstract Snowy Egret (Egretta thula) kleptoparasitism of Elegant Terns (Thalasseus elegans) at a southern California breeding colony entailed piracy of fish from recently fed chicks, adults feeding chicks and adults engaged in courtship feeding.

Notes on the Cayenne Tern in Uruguay

The Cayenne Tern (Thalasseus eurygnathus = Sterna eurygnatha = S. sandvicensis eurygnatha) is widely distributed over more than 12,000 km, from southern Caribbean Islands (120N), along the coast of Colombia and the coast and islands off Venezuela, through Surinam, Brazil, and Uruguay, and to Argentina as far as Puerto Deseado (Chubut errore = Prov. Santa Cruz, 480S) (Hellmayr and Conover 1948:326-327; De Schauensee 1966:110). This bird is one of the least known of the terns and