Like most owls, the species is generally nocturnal, though may be crepuscular at times (or active at dawn and dusk), retiring to roost in secluded spots within the branches of trees.

As with all owls, the morepork has supreme night vision and excellent hearing, able to locate a tiny lizard or rodent from many metres above and away.

[1] The morepork was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae.

[4] Gmelin based his description on the "New Zeeland owl" from Queen Charlotte Sound that had been described in 1781 by the English ornithologist John Latham in his multi-volume A General Synopsis of Birds.

[8] Three subspecies are recognised:[8] Both Gerlof Fokko Mees and Ernst Mayr regarded the taxonomy of the boobook owl as extremely challenging,[9] the latter remarking in 1943 that it was "one of the most difficult problems I have ever encountered".

[10] In his 1968 book Nightwatchmen of the Bush and Plain, Australian naturalist David Fleay observed that the boobooks from Tasmania more closely resembled those of New Zealand than those from mainland Australia, though he followed Mees in treating them as a single species.

[11] Janette Norman and colleagues tested the cytochrome b DNA of three subspecies (as well as the powerful and rufous owls) to ascertain whether the closest relative was used in breeding with the last surviving female of the Norfolk boobook.

The feathers of the underparts are mostly dark brown with buff and white spots and streaks, with the larger markings on the belly making it look paler overall.

[21] In New Zealand, it primarily inhabits forests dominated by Podocarpus, Nothofagus, Metrosideros, and other hardwoods, up to the alpine tree line.

[22] Although their main hunting technique is perch-and-pounce, they are agile birds with a swift, goshawk-like wing action and the ability to maneuver rapidly when pursuing prey or hawking for insects.

They hunt a variety of animals – mainly large invertebrates including scarab and huhu beetles, moths and caterpillars, spiders, grasshoppers, and in New Zealand, wētā.