Queen Alexandra’s Birdwing: World’s Largest Butterfly

Queen Alexandra’s birdwing is the largest butterfly on Earth, and it’s not even close. Females can stretch their wings to 28 cm (11 inches) across – wider than a dinner plate. Males are smaller at around 20 cm (9 inches), but they make up for it with electric green-blue coloring that’s hard to forget once you’ve seen it. This butterfly only lives in one place: the coastal rainforests of Papua New Guinea. And it’s running out of room.

The species is classified as endangered under IUCN Red List criteria, and it’s been on CITES Appendix I since 1987 – meaning international trade is banned. Between logging, oil palm expansion, and a volcanic eruption that wiped out a chunk of its habitat in the 1950s, this butterfly has been losing ground for decades.

Key Takeaways

• Queen Alexandra’s birdwing holds the record as the largest butterfly species alive today, with females reaching 28 cm wingspans
• It lives exclusively in a small strip of coastal rainforest in Papua New Guinea’s Northern Province
• The species is endangered, primarily because of habitat destruction from logging and palm oil farming
• Its caterpillars can only survive on one type of plant – the Aristolochia pipevine – which makes it especially vulnerable when forests are cleared

What Makes Queen Alexandra’s Birdwing So Unusual

Most people hear “biggest butterfly” and picture something a little larger than a monarch. Queen Alexandra’s birdwing blows that expectation away. The females – which are actually the larger sex in this species – have brown wings marked with white spots and triangles. They’re not flashy, but their size alone is enough to stop you in your tracks.

The males are the ones that get all the attention in photographs. Their wings are a deep emerald green-blue with black veining, and their abdomens are bright yellow. Scientifically named Ornithoptera alexandrae, the species was first described in 1907 after a collector (Albert Stewart Meek) shot the first known specimen out of the air with a shotgun. He reportedly thought it was a bird.

That anecdote tells you everything about the scale of this butterfly. It’s large enough to be mistaken for a bird from a distance, and it flies high in the rainforest canopy – often 15 to 20 meters above the ground – which is part of why it stayed unknown to Western science for so long.

Size Comparison with Other Butterflies

Looking at that table, the gap is pretty staggering. A Queen Alexandra’s female is nearly three times the wingspan of a monarch. Even the largest morpho butterflies only reach about 20 cm – the same as a male birdwing, and still well short of the females.

Where Queen Alexandra’s Birdwing Lives

You won’t find this butterfly anywhere outside a narrow strip of lowland rainforest in Papua New Guinea’s Northern (Oro) Province. The 2018 IUCN Red List assessment puts the actual area of occupancy at just 128 to 140 km², split into two completely separate populations within an 8,710 km² extent of occurrence near the town of Popondetta. That is smaller than the city of Las Vegas, divided across patches that no longer connect to each other.

They need this specific type of forest because their caterpillars feed exclusively on Pararistolochia pipevines (formerly classified as Aristolochia), and primarily one species, Pararistolochia dielsiana, which grows in the understory of these lowland rainforests. No pipevines, no caterpillars, no butterflies. It’s that simple. The adults feed on nectar from large flowers like hibiscus, and they tend to fly high in the canopy, which is why casual visitors to PNG rarely spot them.

The problem is that this small range has been shrinking steadily. In 1951, Mount Lamington erupted and destroyed a significant portion of the butterfly’s forest habitat. Since then, logging operations and oil palm plantations have eaten into what was left. The forest doesn’t grow back on a human timescale – these are old-growth trees – so every hectare cleared is effectively gone.

Life Cycle of Queen Alexandra’s Birdwing

Like all butterflies, Queen Alexandra’s birdwing goes through four life stages: egg, larva (caterpillar), pupa (chrysalis), and adult. But the details of each stage are unusual for a butterfly this size.

Females lay their eggs on the leaves of Aristolochia pipevines. When the eggs hatch, the caterpillars start feeding on the plant’s leaves immediately. Here’s the interesting part – the pipevine contains aristolochic acids, which are toxic to most animals. The caterpillars absorb these toxins and store them in their bodies, making both the caterpillars and the adult butterflies poisonous to predators. It’s a built-in defense system.

The caterpillars go through several molting stages (called instars) over the course of about six weeks. They’re spiny and dark-colored, with a bright red patch – a classic warning signal to birds and other predators. When they’re fully grown, they form a chrysalis, and the transformation to adult takes roughly a month. Adults can live for about three months, spending most of their time high in the canopy.

Why Queen Alexandra’s Birdwing Is Endangered

The short answer is habitat loss. The longer answer involves a combination of factors that have stacked up against this species over the past 75 years.

The 1951 Mount Lamington eruption destroyed a large area of primary rainforest within the butterfly’s range. That was a natural event and nobody’s fault, but the forest never fully recovered before human pressures piled on. Starting in the 1960s and 70s, commercial logging operations began clearing old-growth timber from the Northern Province. Then came oil palm – PNG’s oil palm sector grew rapidly from the 1990s onward, and the lowland coastal forests where the birdwing lives were prime targets for conversion.

Illegal collecting is another pressure, though it’s harder to quantify. Because the butterfly is so rare and so visually striking, specimens can fetch high prices on the black market. A single mounted pair has reportedly sold for over $10,000. The conservation community has pushed back against this through CITES enforcement and local education programs, but it’s an ongoing problem.

The Black Market for the World’s Largest Butterfly

Queen Alexandra’s birdwing is one of only four insect species listed on CITES Appendix I, the strictest tier of international wildlife trade protection. The other three are also birdwings, all from the same Indo-Pacific region. Being on this list means every cross-border sale of a wild specimen is illegal, full stop, even for museums or accredited researchers without a permit.

The ban has not stopped the trade. A 2007 US federal case against Japanese collector Yoshi Kojima, described by NBC News as the largest butterfly smuggler ever prosecuted in the United States, documented Queen Alexandra’s birdwing specimens selling for $8,500 to $10,000 each on the underground market. Kojima pleaded guilty after a US Fish and Wildlife Service sting operation, having shipped CITES-listed birdwings to private collectors for years.

The price reflects supply, not demand for live insects. Most underground buyers want preserved, mounted pairs for private display cases, and each specimen taken from the wild is one breeding adult lost from a population that already cannot afford it. That is why CITES enforcement and the local butterfly conservation programs are now pushed together as a paired strategy by groups working in Papua New Guinea’s Northern Province.

Conservation Efforts That Are Actually Happening

One of the more creative conservation approaches for Queen Alexandra’s birdwing is butterfly ranching. Instead of trying to stop locals from interacting with the species entirely, ranching programs encourage communities to cultivate pipevine plants and create habitat corridors where the butterflies can breed naturally. Ranched specimens (bred in semi-wild conditions, not collected from the wild) can be legally sold, giving local people an economic reason to protect the forest rather than clear it.

The PNG government designated the Managalas Plateau area as a conservation zone in the 1990s, and several NGOs have been working with local landowners on reforestation projects that specifically include Aristolochia plantings. The WWF has been involved in some of these efforts, partnering with local communities to develop land management plans that balance agriculture with conservation.

Progress is slow. The butterfly’s tiny range and specialized diet make it especially fragile – you can’t just relocate a population to a different forest and hope for the best. The pipevines need to be there, the canopy needs to be intact, and the specific microclimate of lowland coastal rainforest needs to be preserved. That said, the ranching programs have shown real results, and local awareness of the butterfly’s value (both ecological and economic) has grown significantly since the early 2000s.

A 2023 genomics study published in Genome Biology and Evolution sharpened the urgency. Researchers sequenced full genomes from both surviving populations and found one of the two has notably lower genetic diversity, a signature of a recent population bottleneck. Low diversity makes a species more vulnerable to disease and less able to adapt as the climate shifts, even before a single tree is logged.

What You Can Do

If you’re reading an article about the world’s largest butterfly, you probably care about butterflies more than most people. Here are a few things that actually make a difference, rather than the usual “raise awareness” platitudes:

• Check your palm oil. Certified sustainable palm oil (RSPO-certified) isn’t perfect, but it’s better than the alternative. The products in your pantry are connected to forests in PNG and Southeast Asia whether you think about it or not
• Support organizations working directly in PNG. The butterfly and wildlife conservation space is full of feel-good nonprofits that don’t do much on the ground. Look for ones with actual field programs in the Northern Province
• Don’t buy wild-caught specimens. If you’re a collector, make sure any birdwing specimens you purchase are ranched, not poached. Reputable dealers will have documentation
• If you visit PNG, hire local guides who are involved in conservation programs. Tourism money that flows to communities protecting butterfly habitat reinforces the economic case for keeping the forest standing

Queen Alexandra’s birdwing has survived volcanic eruptions, decades of logging, and the relentless expansion of agriculture into its home. It’s still here – but just barely. The next 20 years will probably decide whether it stays that way.