The world's largest butterfly: Queen Alexandra's Birdwing (Ornithoptera alexandrae) - WWF maximum cards from Papua-New Guinea

The above image shows the male of Queen Alexandra's Birdwing (Ornithoptera alexandrae).

The above image shows the female of Queen Alexandra's Birdwing (Ornithoptera alexandrae).

They are as big as some birds, and they fly like some birds - but they are butterflies!

"Birdwings are papilionid butterflies native to the Indian Subcontinent, mainland and archipelagic Southeast Asia and Australasia, and are usually regarded as belonging to three genera:Ornithoptera, Trogonoptera and Troides. Some authorities include additional genera. The exact number of species is debated, but most recent authorities recognize between 30 and 40. Birdwings are named for their exceptional size, angular wings, and birdlike flight."

http://en.wikipedia.org/wiki/Birdwing

The females of Queen Alexandra's Birdwing are bigger than the males.

Here's an image of a female:

Hovercraft:

"Courtship is brief but spectacular; males hover above a potential mate, dousing her with a pheromone to induce mating. Receptive females will allow the male to land and pair, while unreceptive females will fly off or otherwise discourage mating. Males are strongly territorial and will see off potential rivals, sometimes chasing small birds as well as other birdwing species."

No more shotgun approach:

"The species is also highly prized by collectors, with illegally traded specimens selling for thousands of dollars. Although collectors are often implicated with the decline of this species, habitat destruction is the main threat. Early collectors, frustrated by the height at which adults fly during the day, often used small shotguns to down specimens. but because collectors demand high quality specimens for their collections, most specimens are reared from larvae or pupae."

http://en.wikipedia.org/wiki/Queen_Alexandra's_Birdwing