Above the forest line in the Southern Alps in the South Island of New
Zealand are extensive areas partly covered in scrub and tussock,
partly bare rocks and shingle, and mostly precipitous and difficult to
traverse. This entire region is exposed to an unforgiving mountainous
climate, snow and bleak winds in winter, mist and wind in summer. It
is here, and in the upper margins of the beech forest, that the Kea,
the world’s only mountain parrot, has evolved a level of intelligence
that rivals that of the most sophisticated monkeys.
The Kea has
become the stuff of legends, not only in Phillip Temple’s wonderful
books but also in the minds of those who have come contact with this
extraordinary bird, the clown of the mountains and, more darkly, the
feathered wolf.
In the spring, the Kea digs up large mountain daisies in the alpine
grasslands and searches at the edges of the snow mounds and around
rocks for low growing plants and insects. In the summer they forage in
the alpine shrubs for fruit, seeds and flowers. They feed from rata or
mountain flax, lapping up the nectar and pollen and also catch
numerous grasshoppers, beetles and grubs. The autumn they spend in the
beech forests, eating shoots, leaves and nuts. But the winter is the
cruelest time when many die of starvation. They seek animal fat and
will tear open carcasses to consume meat and internal organs.
One small community of Keas haunts a desolate valley where the
mountains run steeply down into the sea and where there are also
colonies of sooty shearwaters, “mutton birds”. The mature birds are
not to be seen during the day as they are out fishing but at night
they return to their young in nest holes they have dug in the turf
among the boulders. The squabs by the time they are four months old
have been fed so well on the semi digested fish brought back by their
parents that they are full of fat and weigh a couple of pounds. The
locals used to harvest them in great numbers. So do the Keas.
A Kea stalks through the warren of shearwater nest holes, bending
down every now and then, head cocked to listen. The shearwater chicks
crouch silently in their burrows but occasionally they call. The Kea
reacts swiftly and starts to dig. Using its beak like a mattock it
tears away the earth around their burrow’s entrance and reaches
inside. The mutton–bird is not entirely defenseless and may squirt
fish oil into the Kea’s face. The beak that is so effective as a
mattock now becomes a billhook and rips the young shearwater to
pieces.
It is this murderous behaviour of the Kea and its propensity to
attack merino sheep on high country stations which has made the bird
so controversial and led to its persecution, the slaughter of as many
as 150,000 of these birds over the past 130 years. For more than a
century biologists have debated its character but more recent research
throws new light on its extraordinary behaviour and history.
The ancestor of the three species of parrot in the genus Nestor,
the Kea, its brown cousin the Kaka and their close relative the
Norfolk Island Kaka, probably came from Australia. The ancestral
Nestor may have arrived in New Zealand as many as 20 million years
ago. With climate change and the separation into smaller islands in
the early Pleistocene, two distinct populations developed. The
population in the more benign north became Kakas specialising in
exploiting fruit and nectar while the southern population living in
the harsher environment where beech forest dominated, became Keas,
developing the behavioural strategies and food preferences that would
help them survive among the ice fields. There the Kea remained, an
uncommon species of harsh and marginal habitats, no doubt following
the great eagle and other predators for leftovers as well as plaguing
the millions of petrels and shearwaters who bred on the mainland,
until the first wave of humans arrived.
When forests were burned and the Moas were hunted to extinction and
the Polynesian rat eliminated most of the shearwaters from the
mainland, Keas shifted to other sources of food. As dietary
generalists they were relatively resistant to the environmental
changes that forced many other birds into extinction.
The second wave of human settlement brought a bonus to the Kea.
While the Kaka declined as the bush was felled and burned, the Kea
population exploded with the advent of European settlement of the high
country during 1840s and 50s. When sheep began to die in snowfields,
Keas rediscovered a lucrative livelihood as scavengers and even
attacked live sheep. Numbers increased dramatically. This ability to
tolerate massive environmental change and make the most of new
opportunities sets the Kea apart from nearly every other island
species.
This ability to adapt and survive arises out of the Kea’s social
organisation and its propensity to play. Like coyotes, crows and
humans, Keas are “open–programme” animals with an unusual ability to
learn and to create new solutions to whatever problems they encounter.
Exploring and manipulating the objects in their environment, Keas were
selected primarily for individual rather than social learning. In
essence keas were selected to play, since only through play could the
requisite level of flexibility be achieved. Its boldness,
destructiveness and curiosity are aspects of play, scientists say.
The Kea was not fully protected until 1986 when high country
farmers were persuaded to give up their legal right to shoot Keas in
exchange for an undertaking by the government agencies to investigate
all reports of Kea attacks on sheep and to remove all problem birds.
Ski-field operators were encouraged to make their equipment proof
against the Kea’s powerful beak. In this way we are learning to live
with and to give room to our wildlife.