Strigopidae New Zealand Parrots
Version: 1.0 — Published March 4, 2020
Introduction
These three New Zealand endemics all bear Maori common names. Populations of the Kaka and the Kakapo are hanging on in protected remnants of once-widespread ranges on both the North and South Islands. Their shared peril may be their most obvious similarity: A smart and opportunistic pirate, the gregarious and garrulous Kaka is at home in the canopy. The Kakapo is flightless, though it is a decent jogger and an agile climber. Largely nocturnal, the Kakapo has a lek mating system based on low-frequency booming displays. The third species, the Kea, has thrived until recently in its alpine habitat. One of the most intelligent birds, this inquisitive mischief-maker is now studied for its innovative tool use and problem-solving ability.
Habitat
All three species occupy native forests, with the Kea Nestor notablis preferring higher elevations in the South Island. Strigops is now limited to offshore islands protected from introduced terrestrial predators.
Diet and Foraging
Nestor species, like most other parrots, eat a wide variety of fruits, seeds, nuts, invertebrates, and, occasionally, meat from carcasses. The larger bills of males appear to give them greater access to wood-living grubs and some large hard nuts. The Kea is probably the most important disperser of fruit seeds in the alpine region of New Zealand. The Kaka N. meridionalis depends a great deal on honeydew from scale insects during the breeding season. Strigops is strictly vegetarian, taking a wide variety of leaves, fruit, seeds, and nuts, and, unlike other birds, grinding its food in its mouth rather than its gizzard. Like other vegetarian birds, it appears to have a foregut bacterial flora that aids digestion, and its breeding seasons are dictated by the irregular mast-fruiting of key fruiting species.
Breeding
Strigopids are unusual among psittaciforms for the flexibility of their mating systems. The Kaka appear to be monogamous, the Kea polygynous or monogamous, and the Kakapo lek-mating polygynous with no pair bond. All strigopids nest in burrows, crevices, and hollows, most near the ground, but the Kaka’s nests are often quite high up in tree cavities or artificial nest boxes. Strigopids lay 1 to 5 eggs, with 4 the typical clutch size for Nestor species and 2 the most common for Strigops. Female Strigops do all parental care, but in Nestor, males feed the females while they are incubating, and they feed the chicks, via the females, during the nestling phase, but they appear to take a larger role feeding and attending the young once they’ve fledged. Incubation in Strigops takes about a month, and the downy chicks take about three months before they leave the nest, still attended by the female for months after fledging. In Nestor, incubation takes about three weeks, and the nestlings fledge at about 70 to 90 days post-hatch.
Conservation Status
All of these birds have suffered tremendously from the introduction of rats, stoats, and cats to an ecosystem that formerly lacked any terrestrial predators, and all three are at risk (1 VU, 1 EN, 1 CR); an endemic Nestor species on Norfolk Island went extinct soon after European contact in the 19 century. The Kakapo is critically endangered, with a 2014 population size of 126 individuals up from its nadir of 65 in the mid 1990’s. At that time, all wild Kakapo were transferred onto four offshore, predator-free islands, and an intensive program of captive breeding and monitoring was initiated. The Kaka is endangered and persists on predator-free offshore islands and a few mainland sites where terrestrial mammalian predators are controlled or were eliminated; it suffers as well from competition with introduced bees, wasps, and marsupials for honeydew from scale insects. The Kea is considered only vulnerable, yet it appears to be declining over much of its range.
Systematics History
These New Zealand parrots were traditionally placed in the larger parrot family Psittacidae, but recent molecular studies show that Strigopidae is sister to a clade formed by Cacatuidae and Psittacidae (de Kloet & de Kloet 2005, Tavares et al. 2006, Wright et al. 2008, Joseph et al. 2012). Relationships in this small family are well resolved: the Kakapo is sister to the two Nestor species (de Kloet & de Kloet 2005, Tavares et al. 2006, Wright et al. 2008).
Conservation Status
Least Concern |
0%
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Near Threatened |
0%
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Vulnerable |
25%
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Endangered |
25%
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Critically Endangered |
25%
|
Extinct in the Wild |
0%
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Extinct |
25%
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Not Evaluated |
0%
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Data Deficient |
0%
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Unknown |
0%
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Data provided by IUCN (2023) Red List. More information