Some only become active as evening approaches, and while butterflies appear delicate, several Hong Kong species undertake lengthy annual migrations. Here’s how to identify some of the most eye-catching species.

Identification basics: Mormons and peacocks

First, you’ll need to learn how to identify at least some butterfly species, perhaps with the help of a field guide. If you start with swallowtails, you will soon learn that not all have elongated tail streamers. None have proper tails as “tails” on butterflies are extensions from the hind wings.

Hong Kong wild animals and where to find them

The most common local swallowtail is a modest size, with a wingspan of around 8cm (3 inches), and mostly black with white bands or patches towards the rear of the wings. Its cousin, the great Mormon, is far more impressive, as it’s around 50 per cent bigger. The females are a striking combination of black and white with small reddish patches, while males are shimmering blackish blue, also with reddish patches.

Both Mormons are relatively easy to observe while they spend a few seconds gathering nectar from flowers.

The Paris peacock is among other butterflies that behave similarly and has a metallic green sheen, sometimes with a blue patch on each wing for an extra wow factor.

Whirring wings: bluebottles, jays and the dragontail

If you see a butterfly appearing as little more than a blur of rapidly beating wings as it moves from one flower to another, this could be a common bluebottle, with a large blue band on each black wing, or a common jay, with mottled black and soft blue wings.

You will have to be quick to note the features, and quicker to press the shutter at the right time if you are taking photos, as these butterflies seem determined to live life in the ultra-fast lane, and soon dash off to find more flowers.

‘Like someone was drilling into my foot’, snake bite victim says

Hong Kong’s smallest swallowtail – the white dragontail – has even faster wing beats, akin to a hummingbird. It is black and white, with transparent fore wings and long slender tail streamers you can best admire when one briefly alights.

The dragontail is uncommon, but can be seen at Fung Yuen Butterfly Reserve, east of Tai Po Market.

Butterfly royalty: birdwings

Fussy eating habits account for the scarcity of Hong Kong’s two largest swallowtails – and largest butterflies – the common and golden birdwings, both with a wingspan of up to 16cm – wider than a US dollar bill. These have similar patterns, with black forewings graced by slim pale stripes, and mostly yellow hind wings. I have seen them occasionally, flying serenely over treetops, their wings arrayed to form a wide triangular shape as they glide on by.

Toxic tigers

Some butterflies also seem remarkably relaxed as they flap from flower to flower near the ground.

These include the common tiger, named for its bright orange and black patterning that also features white wing spots.

You might expect these are tempting, easy targets for insectivorous birds. But their colours are a warning, as common tiger caterpillars feed on plants containing chemicals that are poisonous to most creatures, and retain these toxins when metamorphosing to adults. Birds that do try them quickly learn their lesson.

Common tigers are relatives of monarchs, the famously migratory butterflies of North America.

They are likewise migrants, with thousands or tens of thousands arriving in Hong Kong during late autumn, and gathering at a few sites for a few weeks. But unlike the monarchs, their migrations are poorly known, with no one yet sure where they head after leaving here in late winter.

On guard! The great egg-fly

Another attractive butterfly is even more of a show-off. Male great egg-flies have black wings, with big smudges on them blending brilliant blue and light blue. They are territorial, perching prominently on leaves or footpaths, and watching for other butterflies – which they may chase after, unless one happens to be a potential mate.

Unusually for butterflies, the females may guard their eggs from predators such as ants and wasps.

Fruit-eating fauns and archdukes

Large fauns are relatively drab, yet if you stroll woodland trails you will surely notice these brown butterflies as they fly up from the ground just in front of you, revealing orange tints on their wingtips. They feed on fallen fruit, and there might be a dozen or more under a fig tree.

Nowadays you might also see more brightly coloured butterflies called common archdukes feasting – the males blackish-blue with pale blue hind wings, the females brown with bands of yellow spots.

Quirky trait of nature: gynandromorphs

Watching and recording butterflies also helps indicate other environmental changes, too often as areas of woodland and scrubland are damaged and destroyed by development. Then there is a chance of spotting one of the quirkiest traits of nature: a gynandromorph.

I’d never heard of gynandromorphs when my son pointed out a strange butterfly on our front door one day. It looked to me like two species in one individual, surely a hybrid, and I grabbed a few photos.

But I soon learned it was actually two sexes in one individual: it had developed as a female on the left side, but a male on the right. And as it was a great Mormon, the left and right sides looked very different – the male wings were bigger, and dark blue rather than black with white patches.

The gynandromorph flew off, and I did not see it again. Yet I received emails from local moth and butterfly experts, such as Roger Kendrick, who likened the find to winning the Mark Six, and James Young, who noted the Hong Kong Lepidopterists’ Society had just two specimens of gynandromorphs.

So even someone with a casual interest in butterflies might stumble across a significant observation. And if not, there is a lot of pleasure to be gained in watching and photographing butterflies, and in learning a little of their world.

Butterfly watching tips

You should be able to find butterflies in several urban parks, providing officials haven’t been too zealous in arranging, tidying and pesticide spraying. Country parks and their margins are better, and there are a handful of butterfly gardens, with plants to attract wild butterflies, such as in Shing Mun Country Park.