The Papuan eagle (Harpyopsis novaeguineae) is a large bird of prey. It is also known by several other names, including Papuan harpy eagle, New Guinea eagle, New Guinea harpy eagle, or kapul eagle, the latter name from the local name for a usually arboreal, marsupial that the eagle is known to regularly hunt. This is an endemic species to New Guinea, and it can occasionally be found throughout the island. This is a forest-dwelling species, usually occurring in mature rainforest. The Papuan eagle is a fairly little-known species for a large eagle; however, it is known to prey on a wide range of prey, probably by and large mammals and birds from small to quite large sizes. What little study has been conducted about their breeding habits suggests they nest in a large forest tree, perhaps every other year. The Papuan eagle is probably naturally scarce, but it is under the threat of habitat destruction by deforestation, as well as hunting. Due to its small and declining population, the species has been classified as vulnerable by the IUCN.
The New Guinea eagle is a fairly large eagle and very large raptor. Though the sexes are similar, the female is slightly larger than the male, with a range up to a 34% size difference. In total length, adults range from 75 to 90 cm. The relatively short but broad wingspan, as expected in forest-dwelling raptors, is 121 to 157 cm. The body mass widely reported is relatively light for so large a raptor at 1.6 to 2.4 kg. The weights reported according to some authors probably underrepresent their size, especially those of full-grown females, and their body size range based on linear dimensions (the weighed birds could have been all smaller males).