This moderately common inhabitant of our fields and beaches shows the problems we have with names. First, some authorities regard it as one with a widespread northern species, some split it off as a different species, Gelochelidon macrotarsa. Gould thought it was different, ‘a fine species of Tern, which proved to be new to science’, and called it the Long-legged Tern.
If a separate species it needs a new English name (and a Spanish one, and one in Indonesian, Japanese, Chinese etc.) IOC Worldbirdnames has given English-speakers ‘Australian Tern’, something that might come as a surprise to Australians, who learn they have their very own tern, along with China, Peru and Caspia. ‘Our tern’, however, is shared with Indonesia and Papua New Guinea, and to a small extent, with New Zealand.
Another name, which at the moment might, by a narrow margin, be called the more usual, is ‘Australian Gull-billed Tern’. This indicates that we have a ‘Gull-billed Tern’ which happens to be (largely) Australian. ‘Largely Australian Gull-billed Tern’, while accurate, would be too long.
The IOC people are reluctant to use ‘Australian Gull-billed Tern’ because they would then need to add an adjective (for example ‘Northern’ or ‘Common’) to the widespread northern species, long known as ‘Gull-billed Tern’. This, on a balancing of relative convenience to those affected, they do not wish to do. There can be only one Gull-billed Tern, they say. The objection to ‘Australian Tern’ on ground of novelty is met by the reassurance ‘People will get used to it’. Perhaps. Given enough time, people will get used to anything. So much for the possibility of worldwide agreement on English names.
As it happens the REAL Gull-billed Tern also occurs on the coasts of north-western Australia, sometimes outnumbering the Australian G-b T.