At least one observer has reported that the kea is polygynous, with one male attached to multiple females.
The same source also noted that there was a surplus of females.

Kea are social and live in groups of up to 13 birds.
Isolated individuals do badly in captivity, but respond well to mirror images.

In one study, nest sites occur at a density of one per 4.4 square kilometres (1.7 sq mi).
The breeding areas are most commonly in southern beech (Nothofagus) forests, located on steep mountainsides.
Breeding at heights of 1,600 metres (5,200 ft) above sea level and higher, it is one of the few parrot species in the world to regularly spend time above the tree line.
Nest sites are usually positioned on the ground underneath large beech trees, in rock crevices, or dug burrows between roots.
They are accessed by tunnels leading back 1 to 6 metres (3.3 to 19.7 ft) into a larger chamber, which is furnished with lichens, moss, ferns, and rotting wood.
The laying period starts in July and reaches into January.
Two to five white eggs are laid, with an incubation time of around 21 days, and a brooding period of 94 days.

Mortality is high among young kea, with less than 40% surviving their first year.
The median lifespan of a wild subadult kea has been estimated at five years, based on the proportion of kea seen again in successive seasons in Arthur's Pass, and allowing for some emigration to surrounding areas.
Around 10% of the local kea population were expected to be over 20 years of age.
The oldest known captive kea was 50 years old in 2008.
At least one observer has reported that the kea is polygynous, with one male attached to multiple females. The same source also noted that there was a surplus of females.
Kea are social and live in groups of up to 13 birds. Isolated individuals do badly in captivity, but respond well to mirror images.
In one study, nest sites occur at a density of one per 4.4 square kilometres (1.7 sq mi). The breeding areas are most commonly in southern beech (Nothofagus) forests, located on steep mountainsides. Breeding at heights of 1,600 metres (5,200 ft) above sea level and higher, it is one of the few parrot species in the world to regularly spend time above the tree line. Nest sites are usually positioned on the ground underneath large beech trees, in rock crevices, or dug burrows between roots. They are accessed by tunnels leading back 1 to 6 metres (3.3 to 19.7 ft) into a larger chamber, which is furnished with lichens, moss, ferns, and rotting wood. The laying period starts in July and reaches into January. Two to five white eggs are laid, with an incubation time of around 21 days, and a brooding period of 94 days.
Mortality is high among young kea, with less than 40% surviving their first year. The median lifespan of a wild subadult kea has been estimated at five years, based on the proportion of kea seen again in successive seasons in Arthur's Pass, and allowing for some emigration to surrounding areas. Around 10% of the local kea population were expected to be over 20 years of age. The oldest known captive kea was 50 years old in 2008.
Kea