I’ve been waiting to see the beautiful Richmond birdwing butterfly (Ornithoptera richmondia) since I moved to the Northern Rivers (18 years ago). Admittedly I have not tried very hard – didn’t go to likely places of encounter. But now I have seen one – outside the lounge room window! It’s a great, colourful thing with a most graceful, swooping flight on big wings. I thought I’d never see one, as it is a threatened species. This is a male, in the flowering frangipani tree.
The maximum wingspan is said to be about 10.5 cm, and this one seemed about that. The female is not quite so colourful, but has a bigger wingspan (up to 11.5 cm). The green of the top of the wings of the male (photo below) first caught my attention as it sailed by.
The species is threatened in New South Wales, vulnerable in Queensland, according to Braby’s Complete Field Guide to Butterflies of Australia (CSIRO, 2016) (contrary to Wikipedia).
The Richmond Birdwing Conservation Network has a mission to increase the numbers via increasing the host plant (the Richmond birdwing vines: Pararistolochia praevenosa in the lowlands and P. laheyana in the higher areas) and also the habitat that the vines and butterflies – at all stages of the life cycle – need). The FAQ of the network gives a lot of information about the butterfly, its lifestyle and range. A short version is :
- The life cycle is a little different in higher and lower altitudes. At my place (lower altitude, below 600 metres), there are two breeding seasons when the adults emerge: between September and November and then from January to March (long daylight hours, high temperatures and high humidity).
- The adult butterfly lives for 4 to 6 weeks, while the pupa (as long as 7 cm) lasts for about 28 days in the warmer weather, longer in colder weather.
- The female lays 60-100 eggs on different leaves of the Richmond birdwing vine. From up to a few kilometres away, she detects certain chemical signals in the vines that indicate they are at a stage where the caterpillars can eat them.
- The vine is disappearing due to land clearing – once it disappears, so will the butterfly. I assume that the vine is somewhere in the vicinity of the house so I’ll have to keep an eye out for it, and for some pupas and more adults. But ‘[r]esearch has shown that the male will travel up to 4 kilometres from where it pupates while the female will travel up to 30 kilometres from where it pupates’, so it may not be that close after all.
- The adult’s yellow and red colours tell predators (pied currawong, noisy pitta, wasps) that the butterfly is toxic and should not be eaten.
When I first saw the butterfly fluttering by, I took a quick look on the ‘net and thought, ‘Holy moly, it’s a Cairns birdwing – but what is it doing here?’ Further investigation showed that it was our very own Richmond species. The Cairns birdwing (Ornithoptera euphorion) is the largest endemic butterfly in Australia, up to 18 cm in wingspan.
As chance would have it, I have a couple of pinned specimens of the Cairns species, inherited from a friend (thanks, Cate and Bill!). You can see why I made that mistake.