ROYAL TERN – (Thalasseus maximus)
The Royal Tern is part of the same family as the gulls. This species measures around 50 cm (20 in.) long, which is considered large for a tern. It has a black cap with a crest during breeding season. The under parts are white, and the wings and back are light grey. The wing primaries are black. The orange bill is large relative to the head size, and pointed. The legs and feet are black. Outside the breeding season the cap is white with some black spots, but the black crest remains. Both sexes are similar.
This bird species is called ‘Royal’ for its impressive size and appearance. The name ‘Tern’ comes from Old English ‘Stearn’ to design that species. The Latin name ‘Thalasseus’ means ‘fisherman’ and ‘sea’, in reference to the bird feeding behavior. The name ‘maximus’ means ‘the greatest’, in reference to the size of the bird.
The habitat of the royal tern is strictly salt water along the coasts in sheltered bays, lagoons, mangroves or marshes. It will be found inland only after severe storms.
As an opportunistic feeder, the royal tern diet consists mostly of small fish, but also includes crustaceans and other small marine animals. It hunts its prey by flying low over the water surface with its bill pointed down, and dives to seize it.
Royal terns nest in colonies, and the nest is usually built in a scrape on the ground. One leg is laid, and the parents are very defensive of their young. The chicks will gather in a ‘creche’, which can number in the hundreds. Parents are able to identify their own young in that crowd and will only feed them. Parental care extends for several months.
The royal tern does not breed on PEI, and observations of this seabird on the island have been recorded as ‘accidental’ (summer season) so far. Its breeding range extends along the USA east and west coasts down to those of South America except along the Andes, and also along the east coast of Africa. There is some partial migration from the northernmost USA coast range, but it is mostly a year-round resident.
Conservation: although the royal tern is currently listed as of ‘least concern’ by the IUCN, there are some threats to the nesting sites from flooding due to storm surges, as the latter become more severe due to climate change. The waters surrounding the nesting sites are also vulnerable to pesticides. Other threats are overfishing, depriving the royal tern of its sources of food, and water pollution from oil spills and chemicals.