Given its small size, Hong Kong has an astonishing diversity of butterflies, which play an important ecological role because of their close interdependence with plants. According to the Agriculture, Fisheries and Conservation Department, Hong Kong has a checklist of 236 species, accounting for about 11 per cent of all Chinese butterfly species. Macau, by comparison, has only 85 species.

Perhaps the most famous and glamorous of the 200 species identified at Fung Yuen Butterfly Reserve, many of which are classified as rare or uncommon, are the common birdwing (Troides helena) and the closely related golden birdwing (Troides aeacus).

These are the largest local butterflies and the only insects in Hong Kong protected by law. Their wingspan can extend up to an impressive 16cm and they lay their eggs only on the India birthwort plant.

See also Photos: Rare butterfly species in HK

Though much smaller, with a maximum wingspan of 4cm, the rare white dragontail is equally precious and beautiful, and is protected by law in China. There is a dedicated white dragontail garden at Fung Yuen and it is not unusual to see these unique black-and-white insects, with their distinctive extended tails, hovering with rapid wing movement like dragonflies. The tips of their forewings are transparent and they manoeuvre forwards and backwards with apparent ease.