Energetics of South Island Kaka (Nestor meridionalis meridionalis) Feeding on the Larvae of Kanuka Longhorn Beetles (Ochrocydus huttoni)
- Ecology Division, DSIR, Private Bag, Nelson, New Zealand
- Present address: Department of Zoology, Auckland University, Private Bag, Auckland
Kaka (Nestor meridionalis meridionalis) studied in Big Bush State Forest spent 35% of their feeding time digging out Ochrocydus huttoni larvae from live mountain beech trunks (Nothofagus solandri: var. cliffortioides).
Larvae of O. huttoni had a high energy value compared to that of other insects. The assimilation efficiency for energy of two captive kaka was 91 j: 3% when fed a diet of O. huttoni.
Using the energy intake of the aviary birds during the feeding trials, the requirement for existence metabolism at 8.5°C for 593 g kaka was about 490 kJ per day. This was consistent with estimates made using Kendeigh's allometric equations for existence metabolism.
Unless the cost of digging for O. huttoni was less than half that of flying, there would be a net loss of energy for a kaka feeding on the larvae. Kaka would need to balance their energy budget by eating other foods, the abundance of which may be currently threatened.