Queen Alexandra's Birdwing

Ornithoptera alexandrae — Queen Alexandra's birdwing — is the largest butterfly species in the world by wingspan. Females reach 28 cm wingspan and 12 g body weight; males are smaller (~16-20 cm wingspan) but more spectacularly colored, with iridescent blue-green wings outlined in black on a yellow body. The species is endemic to a single area of lowland coastal rainforest in Oro Province, Papua New Guinea — a range estimated at less than 100 km² of suitable habitat. The species has been Critically Endangered on the IUCN Red List for decades and is listed in CITES Appendix I (the strictest international trade prohibition, used only for species facing imminent extinction risk). Caterpillars feed exclusively on Aristolochia (pipevine) species — the larvae sequester aristolochic acids from the host plant, making the adult butterflies toxic and aversive to bird predators (the bright colors are warning signal). The species was first scientifically described in 1907 by Walter Rothschild, after his collector Albert Stewart Meek shot a specimen from the rainforest canopy with a shotgun in 1906 because the butterfly was too high to reach by net. The major contemporary threat is conversion of pipevine-bearing rainforest to oil palm plantations; the 1951 eruption of Mount Lamington also destroyed a significant portion of the historical range. A small captive-rearing program operates in Papua New Guinea but commercial trade is banned.