Australasian Fairy Tern

The fairy tern is a small tern with a white body and light bluish-grey wings. A small black patch extends no further than the eye and not as far as the bill. In the breeding plumage both the beak and the legs are yellowish-orange. During the rest of the year the black crown is lost, being mostly replaced by white feathers, and the beak becomes black at the tip and the base. The sexes look alike and the plumage of immature birds is similar to the non-breeding plumage. The total length of the fairy tern is about 25 cm (10 in).

Fairy terns are surface plungers, feeding on fish that shoal just under the water surface. To forage, fairy terns hover between 5 and 15 metres above the water to search for prey, then carrying out a descending aerial dive beak-first towards the water. They then spread their wings and tails just above the water surface, submerging only their bills and heads to catch their prey. This foraging technique means that they catch prey no deeper than around eight centimetres under the water surface, allowing them to make use of shallow waters, such as tidal pools. Fairy terns seldom go far out to sea but are often to be seen where predatory fish are feeding on shoals of small fish. Fairy tern diets consist predominantly of pelagic schooling fishes. For instance, Australian fairy terns mostly eat blue sprat, hardyheads, and garfishes. Similarly, New Zealand fairy terns have a diet made up of common estuarine fish, namely gobies and flounders, responsible for most of their consumed biomass, as well as shrimps, comprising up to 21% of their diet. Little research has been done on the diet of New Caledonian fairy terns, but given their foraging technique, it is likely that they too forage for small marine fish that school just below the water surface. Fairy terns also consume crustaceans, molluscs and some plant material. …