The decline of the kea, the world's only alpine parrot species, could spell the end of 12 per cent of New Zealand's alpine plants, researchers say.
University of Canterbury lecturer, Dr Ximena Nelson, said those plants which rely on kea for seed dispersal could struggle to survive should the cheeky parrot's numbers diminish further.
"Kea are mischievous and lovable and also threatened, in part because we persecuted them for decades. From the late 1800s until 1971, the government placed a bounty on kea beaks. In the 1920s, the bounty was 10 shillings per beak, equating to $65 today," Dr Nelson said.
"After an estimated 150,000 kea were killed, the wholesale bloodshed ended in a full protection for the species in 1986. However, kea sometimes do still fall foul of a bullet and now it is likely than there are considerably less than 5000 birds left.
"All of this was because of this birds' powerful beak, which can occasionally cause a sheep's death. However, this beak is not only destructive, but also has the power to give life," Dr Nelson said.
University of Canterbury PhD student Laura Young looked at the foraging behaviour of kea and found they spend a large proportion of their time eating fruit. New Zealand's mountains have an unusually high proportion of fruit-bearing plants, making fruit an ideal food for the world's only alpine parrot.
However, to maintain genetic viability the plants need to disperse their seeds and there are few remaining native species that may be able to do the job, Dr Nelson said.
Young's work found that unlike other parrots, the kea's beak does not crush the seeds in the fruit it eats, Dr Nelson said.
"Laura's work showed that kea selected more fruiting species, consumed more fruit and dispersed more seeds than all other birds seen in the mountains combined. When she looked carefully at the seeds contained in hundreds and hundreds of kea faeces, she found that in fact almost all seeds were intact.
"Furthermore, kea are the only species that make frequent long-distance flights within and between mountain ranges. Hence, much of the effective long-distance dispersal of the alpine flora may be currently performed by kea.
"The fact that kea are able to ingest fruit and rarely crush seeds despite their powerful curved 'parrot' beak is noteworthy. These large birds can damage motor vehicles, buildings and signs, yet they can manipulate delicate items with considerable dexterity, providing another good reason to cherish these clever birds."
As well as illegal hunting and pet trade activities, predation, competition for resources with introduced mammals and humans, lead poisoning and habitat degradation have led to the decline in the kea population, Dr Nelson said.