What do Kaka feed on? … It depends on the season.
New Zealand’s endemic Kaka parrot depends most on the native puriri tree for it’s nourishment in the northern half of the country.
Analysis of hundreds of Kaka sighting reports sent in by Kaka enthusiasts and the public, has shown that Kaka are seen and reported in puriri trees more often than in any other single type of tree — native or exotic.
This applies to sightings of North Island Kaka (Nestor meridionalis septentrionalis), in the top half of the North Island, as reported by observers to the KakawatchNZ network.
Puriri trees are mostly found from North Cape to the Waikato in lowland and coastal rainforests on fertile alluvial and volcanic soils. They are one of a few New Zealand trees that produce fruit and flowers together for long periods, and are bird pollinated with seeds bird dispersed.
Puriri Popular All Year
Analysis of Kaka sighting reports for one year, (by extracting observers’ foraging information on each sighting), showed that fruit and nectar from the puriri tree was the most frequently observed food source, says a spokesperson for KakawatchNZ, a network of Kaka observers and enthusiasts.
For the year divided into seasons, most Kaka were reported foraging on pohutakawa in summer, puriri in autumn and winter, and kowhai in spring.
When they were reported foraging on exotics, by season the most frequent sightings, were on eucalypts in summer, pines in autumn and winter, and banksia in spring.
This summary does not reflect the huge variety of other foods that Kaka take during the year, as these include most fruiting and flowering natives and a range of exotics.
Native and Exotic Sources
In summer, Kaka were most frequently observed on natives that included rewarewa, nikau, puriri, kahikatea, flax, and cabbage trees. They were also observed feeding in exotics such as eucalypt species and pinus species.
The foraging emphasis focussed in autumn on natives such as puriri, totara, miro, coprosma and kahikatea with exotics such as pinus and eucalypt species supplementing the Kaka diet, and many observations on the Australian originated banksia trees and domestic pear and apple trees.
Winter is the peak time for Kaka visits to the upper North Island mainland from close offshore islands and many Kaka were observed foraging on native trees and shrubs.
These included puriri, kauri, taraire, kohekohe, nikau, totara, titoki, rewarewa, tree ferns and flax.
Flowers Nectar and Fruit
They were also observed on a wide range of exotics, such as kiwifruit, bottlebrush, pawpaw, pine-nuts, persimmons, feijoa, banksia, apple, magnolia, camelia, pecan, cherry, orange (and other citrus), and fig trees. Pinus and eucalyptus species were also still a major part of their diet.
In spring, observers again spotted Kaka foraging in a wide range of native and exotic trees, including banksia, pecan, bottlebrush, monkey apple, loquat and frangipani trees. Kaka were also feeding in native trees such as kowhai, kahikatea, putaputaweta, puriri, rewarewa, nikau, kauri and totara.
Kaka are omnivrous in that they feed on fruit, nectar, flowers, insect larvae, cone kernals or nuts, and even pine gum. This variety ensures a diverse chemical and nutritional composition to their diet.
Kaka are part-time nectarvores, but nectar alone cannot meet the amino acid requirements of any bird, so other foods are necessary, particularly insects.
Nectar Nutrients Dilute
Nectar provides a very dilute solution of various sugars (mostly sucrose, but also glucose and fructose depending on the plant).
Some flowers also have low concentrations of polysaccharides (amino acids and lipids), but nectar is one of the most nutrient dilute foods consumed by birds (Klasing 1999).
Pollen may also be consumed by Kaka in the process of taking nectar and is high in protein, minerals and vitamins.
From sightings recorded by Kakawatchnz observers, it’s evident that Kaka take nectar all year when they can get it, and that often means taking advantage of exotic sources on the mainland, especially from autumn to spring.
For example, Kaka have been observed licking nectar from a magnolia flower in winter, and then consuming the whole centre part of the magnolia flower.
Insects and Gum Supplements
They are also regularly observed foraging for both native and exotic fruits, from puriri, taraire and kahikatea berries to pawpaw, loquat, mandarin, and many other garden and farmed fruits.
Nuts are taken in the form of cone kernals of pines, eucalypts, kauri and totara trees in particular.
Kaka are also often seen foraging for insects in the bark of many different trees with the observer often attracted by falling bark from above.
Kaka are most often seen stripping bark for insects on pinus species, but also frequently on pohutakawa and eucalypts.
As well as insects, cone producing trees — including exotic pinus such as radiata, pinasta, and macrocarpa, and natives such as araucaria and agathis species — provide a rich source of sap that is high in vitamins and anti-oxidants.
These are usually taken in early spring and are believed to provide the female kaka with a boost before breeding and egg production begins.
The Kaka makes a horizontal cut in the tree bark using its pincer-like bill, and uses its long tongue to lick up the sap that oozes from the cut.
Kaka are well adapted for this omnivorous diet, using their strong bill to open cones and extricate the kernal or seeds, and also using their bill to hang on when foraging.
The parrot jaw joint is uniquely shaped to allow lateral movements of the lower mandible relative to the upper one, allowing the Kaka to use its bill as pincer-like pliers.
KakawatchNZ Network Facebook page of sightings.
Klasing, K.C., 1997, Comparative Avian Nutrition, CAB International Press.
Heather and Robinson, 1997, Field Guide to the Birds of New Zealand, Viking Press.