The tern that had flown across Cook Islands twenty cents since 1972 moved in 2015 to a very different coin: 21 millimetres instead of 28.5 and 3.64 grams instead of 11.31, as the islands’ new circulating series was struck in nickel-plated steel by the Royal Australian Mint.

The reverse shows the bird in flight, the numeral 20 and the initials JB of the artist George James Berry. The obverse has Ian Rank-Broadley’s portrait of Elizabeth II, his initials IRB, the date and the legend ELIZABETH II COOK ISLANDS.

Following its release, the old copper-nickel twenty cents and all other earlier coins lost legal tender status in the spring of 2016.

In UNC the tern and the portrait are untouched by circulation and the nickel-plated field keeps its mint lustre. In a topical collection of birds on coins it looks well beside the large terns of the 1970s to 1990s.

A collection can grow in any direction, and the VPcoins catalogue has options for each of them.