[3][1] Under the New Zealand Threat Classification System the falcon is stable at Threatened, with conservation research needed.

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

[5] Gmelin based his description on the "New-Zealand falcon" that had been described and illustrated in 1781 by the English ornithologist John Latham.

The soft parts that become yellow are instead olive green, sky blue, or dull grey in adolescent falcons under 9 months old.

[8] The native habitats of the New Zealand falcon have been reduced through human development of land for the purposes of agriculture, vineyards, forestry, and housing, impacting nest sites and prey abundance.

[17] Observations of captive falcons stooping rabbits and a cat were noted as playful or territorial rather than for hunting purposes.

[8] The New Zealand falcon has a wide range of prey it hunts, but is mostly made up of live introduced and native birds caught in the air.

[8][18][21][20] The falcon is adept at capturing introduced birds, with their make up in the prey composition being slightly higher than their proportional abundance.

[8][18] As the prey composition is closely related to the local species abundance, studies on the diet of the three forms come with slightly different results.

[22] The southern falcon hunts forest birds as well as seabirds when they come in at dusk, and one was recorded eating a 975g (34.4 oz) little blue penguin.

The more effective search strategy is contour-hugging, a fast flight that follows the shape of the landscape and allows the falcon to sneak up on and attack agile birds.

These techniques lead to quick tail-chases and attacks rather than stalking like other birds of prey due to the fast flying speed of the falcon.

The falcon will stay 2m to 4m (6.6 ft-13.1 ft) behind the bird, and can prevent prey from diving into cover by getting underneath and cutting it off.

Steeper dives are used on larger birds, and multiple stoops can be used to push the prey to the ground so it's vulnerable enough for a direct attack.

The falcon glides down and picks up speed, closing then quickly opening its wings and tail feathers before attacking the prey.

[8] The New Zealand Falcon has also been recorded hunting on the ground, extracting nestlings from tree-hole or crevice nests, and stalking lizards.

[20] Once the New Zealand Falcon subdues its avian, mammalian, or reptilian prey, it kills it by dislocating the neck vertebrate with its beak.

Captive falcons or wild individuals with siblings will spread their wings and tails to cover their newly killed prey with a position called ‘mantling’ before taking it elsewhere to eat.

Caching sites of eastern falcons include high bushes, tussocks, tree-stumps, and small trees, all under 3m (9.8 mi).

[8] In Otago the falcons show a preference for unmodified tussock or riparian habitat with steeper slopes up to 39° for their nest scrapes.

[26][27] Artificial nesting sites have been provided in vineyards for the New Zealand falcon as a pest control and conservation programme.

Nest scrapes within pine plantations are all on the ground as there are no epiphytes or tree cavities that a falcon would use in a native podocarp forest.

During incubation attentiveness stays above 90%, increasing with bad weather conditions and the eggs are left for no longer than 1 minute with exceptions of disturbance events.

[8] The presence of parents and siblings alters their behaviour within this time and should result in a faster development of hunting and flying skills.

Wingspan undertakes conservation, education and research activities related to birds of prey found in New Zealand, and provides demonstrations of falconry.

After the release of a further 15 birds breeding began to occur – the first time it is thought to have happened since land clearance 150 years ago.

Breeding pairs within the vineyards are found to have higher nest attendance, brooding, and better feeding than in nearby natural habitats.

In the 1970s, two decades after being protected, it was estimated that at least 100 falcons were being shot in the South Island each year due to lack of public knowledge and similarity to the swamp harrier.

Both Stewart and the Department of Conservation have claimed that people shooting New Zealand falcons have interests in chickens or racing pigeons.

In Māori mythology the New Zealand falcon acts as a messenger from a young chief in Whāngāpē to the twin sisters Reitū and Reipae in the Waikato he wished to marry.