Butterfly House

The Butterfly House opened in 1985 at Melbourne Zoo, which was founded on 6 October 1862 in Royal Park, Parkville. According to Kate Pearce, the zoo's Manager of Birds and Invertebrates, there was then no large butterfly house of this kind in a public setting in Australia, and a zoo's focus on insects was something new for the country. The zoo describes its construction as the most technically difficult task it had undertaken up to that point, since it had to guarantee stable conditions all year for species whose adult lives last only weeks.

Breeding the butterflies on site, as the zoo did from the start, was also unusual at the time. Over the decades the equipment has been modernised: the roof shades worked by hand in 1985 have given way to computer control of shading, heating, cooling and ventilation. In 2025 the zoo marked the 40th anniversary of what it now calls its heritage Butterfly House, noting that some 900,000 butterflies had been released there since opening.

The Butterfly House is a glasshouse designed to recreate a tropical climate at Melbourne's temperate latitude. Daytime temperatures are held between 28 and 30 °C and night-time temperatures between 20 and 22 °C, with humidity around 75 per cent all year; the zoo sums this up as a steady temperature of about 27 °C.

Shade screens, heating, cooling and ventilation are now computer-controlled, where keepers once operated blinds by hand. Behind the scenes, separate caterpillar greenhouses, closed to the public except on guided tours, hold eggs, caterpillars and chrysalises until the adults are released into the main house. The building sits in the zoo's Forest of Wonder precinct, alongside Sumatran tigers, orangutans and siamangs.

The zoo reports more than 600 butterflies in flight at any time, from 13 or 15 tropical species. The largest is the Cairns Birdwing (Ornithoptera euphorion), whose females span 20 to 25 cm; the smallest, the Common Grass Yellow (Eurema hecabe), measures about 4 cm.

More than 22,000 butterflies are released each year, around sixty a day on average. Females lay eggs on the host plants in the house, and the caterpillars are raised behind the scenes before the adults join the flight hall. Keepers prepare about two litres of nectar a day to supplement what the flowers provide.

The Butterfly House is in the Forest of Wonder precinct of Melbourne Zoo, and entry is included in general zoo admission. Its humid warmth contrasts sharply with Melbourne weather, especially in winter.

The zoo also runs a small-group Butterfly Experience with its invertebrate specialists, which takes in the backstage caterpillar greenhouses, has participants assemble flower or fruit bouquets for the butterflies, and ends with placing them in the house. The surrounding Royal Park makes for a walk afterwards.