A large tern with a shaggy black crest and cap. It feeds mainly on small fish, searching from above the water and diving head-first to catch them.
The upper wings are gray and the underparts white; the yellow bill and deeply forked tail stand out. After breeding, the black cap recedes and the crown becomes mottled gray.
Greater crested terns breed in coastal colonies and mainly eat small fish. At Montague Island off southeast Australia, photographs recorded prey delivered to the colony for 35 days of the 2018 breeding season.
At Montague Island off southeast Australia, photographs recorded prey carried to the colony over 35 days of the 2018 breeding season. Of 2,469 items identified to species or family, Australian anchovy made up 84.5% and dominated every breeding stage. Seven main prey types were identified; barracouta, trevallies and southern calamari were frequent alternatives during incubation and declined after chicks hatched.
Anchovy formed 77.0% of prey delivered to adult partners during incubation, then 92.4% of items brought to chicks. Mean anchovy length was 91.1 mm during incubation, 71.8 mm in early provisioning and 79.6 mm mid-provisioning. Its share also increased with local sea-surface temperature up to about 17.5 °C.
An extinction-risk assessment has not been added yet.
The authors suggest that, because greater crested terns specialize strongly on anchovy, changes in prey composition and size may indicate changes in the pelagic ecosystem off southeast Australia.