Kakapo - Ecology and Behaviour

Ecology and Behaviour

It seems that the Kakapo — like many of New Zealand's bird species — has evolved to occupy an ecological niche normally filled by various species of mammal (the only non-marine mammals native to New Zealand are three species of small bats). Before the arrival of humans, the Kakapo was distributed throughout the three main islands of New Zealand. It lived in a variety of habitats, including tussocklands, scrublands and coastal areas. It also inhabited forests, including those dominated by podocarps (rimu, matai, kahikatea, totara), beeches, tawa, and rata. In Fiordland, areas of avalanche and slip debris with regenerating and heavily fruiting vegetation — such as five finger, wineberry, bush lawyer, tutu, hebes, and coprosmas — became known as "Kakapo gardens".

The Kakapo is primarily nocturnal; it roosts under cover in trees or on the ground during the day and moves around its territories at night.

Though the Kakapo cannot fly, it is an excellent climber, ascending to the crowns of the tallest trees. It can also "parachute" - descending by leaping and spreading its wings. In this way it may travel a few metres (yards) at an angle of less than 45 degrees.

Having lost the ability to fly, it has developed strong legs. Movement is often by way of a rapid "jog-like" gait by which it can move many kilometres (miles). A female has been observed making two return trips each night during nesting from her nest to a food source up to 1 km (0.6 mi) away and the male may walk from its home range to a mating arena up to 5 km (3 mi) away during the mating season (October–January).

Young birds indulge in play fighting and one bird will often lock the neck of another under its chin. The Kakapo is curious by nature and has been known to interact with humans. Conservation staff and volunteers have engaged extensively with some Kakapo, which have distinct personalities.

The Kakapo was a very successful species in pre-human New Zealand and one of the reasons for this was their set of adaptations to effectively avoid predation from native birds of prey, which were their only predators in the past. However, these same behaviours have been of no use to them when faced with the mammalian predators which were introduced to New Zealand after human settlement, because these hunt in different ways. As hunters, birds behave very differently to mammals, relying on their powerful vision to find prey and thus, they usually, (with the exception of owls) hunt by day. Apart from the two surviving New Zealand raptors, the New Zealand Falcon and Swamp Harrier, there were two other birds of prey in pre-human New Zealand: Haast's Eagle and Eyles' Harrier. All four species soared overhead searching for prey in daylight and to avoid these avian predators, the Kakapo's ancestors adopted camouflaged plumage and became nocturnal. In addition, when the Kakapo feels threatened, it freezes, so that it is more effectively camouflaged in the forest vegetation which their plumage resembles. It was not entirely safe at night when the Laughing Owl was active and it is apparent from their nest deposits on Canterbury limestone cliffs that the Kakapo was among their prey.

Mammalian predators, in contrast to birds, rely on their sense of smell and hearing to find prey and often hunt by night. The Kakapo's adaptations to avoid avian predation have thus been useless against its new enemies - this is one of the reasons for its massive decline since the introduction of dogs, cats and mustelids - see Conservation: Human impact. A typical way for humans to hunt down the Kakapo is by releasing trained dogs.