Royal NZ Navy's Bird-class ships

Page 2 – 'Pocket corvettes'

The Royal New Zealand Navy's new Bird-class ships were unusual. Although they looked a little like the Admiralty’s Isles-class minesweeping trawlers, their extended forecastles gave them more of a naval look. In terms of punch and power they slotted somewhere in between minesweeping trawlers and corvettes, as the following table shows:





Standard displacement

545 tons

607 tons

925 tons

Length overall

50 m

51 m

63.5 m

Main gun


102 mm

102 mm

Max speed

10 knots

13/14 knots

16 knots

By 1943 the Birds were being called corvettes in official reports to Parliament.

The best way of thinking of these ships is as multi-purpose vessels optimised to train young New Zealanders in seamanship, minesweeping, gunnery and – unusually for such vessels – even torpedoes. When Defence Minister Fred Jones announced their ordering in December 1939, he called them ‘three small training ships, not unlike trawlers’; two years later, just before their arrival in New Zealand, he spoke of them forming ‘a training flotilla’.

Kiwi, Moa and Tui were also unusual in another way. In the Second World War, the Royal Navy built its small escorts in huge numbers – there were 145 Isles-class ships and nearly 270 Flower- and Improved Flower-class ships. At just three in number, Kiwi, Moa and Tui were very rare birds, a one-off design ideally timed to assist the birth of a new navy.

But, as the war got a lot closer to New Zealand’s shores, these multi-purpose vessels would soon find themselves in the front line of the Pacific War.

How to cite this page

''Pocket corvettes'', URL:, (Ministry for Culture and Heritage), updated 29-May-2023