The genus Nestor represents a very unusual taxon within the order Psittaciformes. This group of birds is together with kakapo (Strigops habroptilus) included in the family Strigopoidea. Although beliefs about phylogeny in parrots can vary a lot, generally we are confident that this family sit on the basal phylogenetic branch of the whole order. So from the common acestor this taxon split as the first one. In captivity we can find the Kea Parrot ( Nestor notabilis ) all around the world. However, the closely related Kaka parrot ( Nestor meridionalis ) is found only on New Zealand and at Stuttgart ZOO in Germany. There are two more extincted species left – Norfolk Kaka (Nestor productus) and recently discovered Chatham Kaka (Nestor chathamensis). In this article we will talk only about the Kaka (Nestor meridionalis)
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Both living species are found on the New Zealand. The Kaka Parrot as the only representative of Nestor genus includes two subspecies – Nestor meridionalis septentrionalis comming from the North Island and Nestor meridionalis meridionalis comming from the South Island. The latter subspecies has duller feather coloration and less distinct red collar. The crown is whitegrey in meridionalis while grey in septentrionalis. Females of this species should have the upper mandibule smaller and generally the male body is bigger as well. We can recognize the youngers because of the whitish periopthalmic ring which becomes darker within the second year. Babies leave the nest 10 weeks after hatching and following 5-6 weeks they are dependent on parents care.
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(c) PhilipC. This file is licensed under the Creative Commons Attribution 2.0 Generic license.
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However, Kea Parrot ( Nestor notabilis ) and Kaka parrot ( Nestor meridionalis ) are definitely not the most popular parrots. We can find many scientific studies about these species. They attract the attention of researchers because of their high level intelligence, the unique position within phylogenetic tree and because they are endangered. In general, New Zealand government spends much funds on nature conservation. That’s why the future of Kea Parrot and Kaka Parrot is probably brigther than for example in case of many Indonesian species.
We can distinguish species which are sexually mature sooner, reproduce faster but so die earlier (zebra finches, budgies, …) and those that reach higher age and their whole life is some kind of „slower“. We could classify Kaka Parrot ( Nestor meridionalis ) to the second group. For example Begs & Wilson mention that during their field research they have observed within 6 years only one successful breeding attempt from a pair. Their reproduction is slow and they invest to reproduction only if there are enough food sources available. Kakas are omnivorous – another unique characteristic in comparison with other parrot species.
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Kaka in flight. (c) Tony Wills. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
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We actually can’t be surprised that such dull colored Kaka wasn’t desirable parrot for exporters but in the past these birds were very popular for native people Maori. Cats, rats and weasels threatened this bird bird as well. Island species are very sensitive to any predation pressure as in their evolutionary history they didn’t face any mammal predator and that’s why they are catched easily. Kakas nest in deep tree cavities where their babies spend a lot of time before they fledge. Afterwards, they stay on the ground so they are an easy target for the predator.
Within the field research researchers found out that many chicks were killed in the nest. That’s why it’s very difficult for species to persist. Although, the deforestation or damages of their natural habitat wasn’t so intensive in here as in other parts of the world, combination and sum of all partial factors leaded to the fact that this species became very rare at the beginning of 90’s. Now we can find it only on several little islands like Kapity Island or Stewart.
Kakas had to face also another trouble – food competitors like Common Brushtail Possums (Trichosurus vulpecula) or Vespulid wasps. Local beech woods are naturally inhabited by true bugs (Ultracoelostoma) which produce like for example aphids sweet secretion. This „nectar“ is a very important part of Kakas diet. Mentioned wasps started consuming it and that’s how parrots lost their food source. Overabundant possums destroy blossoms and fruits of plants when they move through the forest. What is more, they nest in tree cavities just like Kakas and they killed their babies or eggs as well.
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Common Brushtail Possum represents a very serious threat for Kakas. (c) JJ Harrison. This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license.
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Although Kaka parrot is closely related to Kea parrot we can find differences in ecology and behaviour patterns between them, especially in food preferences. Keas eat almost everything they find in their habitat (beechnuts, berries, maggots, small roots, nectar, bird eggs and chicks, carcasses, …) and their behaviour is adapted to that, they are permanently energetic to find as much food as possible. Kakas are omnivorous as well but not so extremely. They eat mostly nuts, fruits, nectar and the sweet secretion from true bugs. Adult birds are conservative and sometimes it can be very difficult to learn them to eat new kind of food.
Proportion of Kaka’s food sources in the wild:
invertebrates – 87,9%
fruits/seeds – 9,9%
green parts of plants – 2,0%
blossoms – 0,3%
Both species have also different age of reaching their sexual maturity and ability of young birds to become independent. Young Kaka parrots migrate from the parents territory 6 months after they leave the nest. At the age of a year they are not recognizable from adult birds and a year after they are sexually mature. However, young Keas stay in „adolesent groups“ for much longer while their parents still help them with finding the food. They reach the same colloration as their parents at three years and become sexually mature at the age of 3-4 years.
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Closely related Kea. (c) gambier20. This file is licensed under the Creative Commons Attribution 2.0 Generic license.
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We can better understand a sociality of species when we know more about the sex ratio in its population. According to observation of ornithologists the ratio Kaka females : males is 1 : 1,27 – 1 : 1,6. As most of parrot species Kaka parrots are monogamic. One study talks about extreme male competition when attacks can lead to death of the defended opponent.
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We have already mentioned natural food sources of Kakas. However, there is still a question how to feed these birds in captivity. Conservationists of this species decided to provide supplemental feed to this species to stimule their breeding success. This mixture was set up on base of their natural nutritional requirements. This is a food portion for one bird per a day:
dates 10g
walnuts 10g
cheese 5g
corn cobs 30g
sunflower 10g
pears 25g
apples 30g
fruit jam 5g
Sources:
*Reintroduction of kaka (Nestor meridionalis septentrionalis) to Mount Bruce Reserve, Wairarapa, New Zealand; Raelene Berry (1998); SCIENCE FOR CONSERVATION: 89
*ENERGETICS OF SOUTH ISLAND KAKA (NESTOR MERIDIONALIS MERIDIONALIS) FEEDING ON THE LARVAE OF KANUKA LONGHORN BEETLES (OCHROCYDUS HUTTONI); J.R. BEGGS† and P.R. WILSON;
*NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 10, 1987
*THE ROLE OF INTRODUCED PREDATORS AND COMPETITORS IN THE DECLINE OF KAKA (Nestor meridionalis) POPULATIONS IN NEW ZEALAND; P. R. Wilson, B. J. Karl, R. J. Toft, J. R. Beggs & R. H. Taylor; Biological Conservation Vol. 83, No. 2, pp. 175 185 1998
*Control of introduced mammalian predators improves kaka (Nestor meridionalis) breeding success: reversing the decline of a threatened New Zealand parrot; Ron Moorhouse; Biological Conservation 110 (2003) 33–44
*Social Play in Kaka (Nestor meridionalis) with Comparisons to Kea (Nestor notabilis); Judy Diamond (2004); Papers in Behavior and Biological Sciences
*SEX RATIO OF NORTH ISLAND KAKA (NESTOR MERIDIONALIS SEPTENTRIONALIS),
*WAIHAHA ECOLOGICAL AREA, PUREORA FOREST PARK; TERRY C. GREENE and JAMES R. FRASER; NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 22, NO. 1, 1998
*THE DIET OF THE NORTH ISLAND KAKA (NESTOR MERIDIONALIS SEPTENTRIONALIS) ON KAPITI ISLAND; RON MOORHOUSE; NEW ZEALAND JOURNAL OF ECOLOGY, VOL. 21, NO. 2, 1997
*Sexual dimorphism in the North Island Kaka (Nestor meridionalis septentrionalis): selection for enhanced male provisioning ability?; RON J. MOORHOUSE; Ibis (1999) 141, 644-651
Title photo: (c) Giles Breton. This file is licensed under the Creative Commons Attribution 2.0 Generic license.
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