I have been writing this blog for a while now so it seem absurd that it has taken this long to write about green parrots – the iconic endemic bird species of Norfolk Island. The answer lies in my desire to only include my own photographs in the blog, and green parrots are hard to photograph. The colour of leaves, often in the shadows, and endangered to boot! Even now, the pictures below don’t really pass muster, but it’s time to tell the story.
The Norfolk Island Green Parrot (Cyanoramphus cookii) is a medium-sized green parrot with red around the face, and blue along the edge of the wing. The genus is represented by a number of species in New Zealand, it’s sub-antarctic islands, Lord Howe and Norfolk Island, New Caledonia and as far as Tahiti. None are in Australia though some species are commonly kept as pets, generally known as kakariki. Given their distribution around small islands, it is no surprise that several have become extinct in modern times, including both species in Tahiti, as well as those on Lord Howe Island and Macquarie Island.
The taxonomy has changed over a period of time, and even now there are differing points of view on the correct classification of the group. The Norfolk Island Green Parrot was once considered a subspecies of the New Zealand Red-fronted Parakeet and more recently as one half of the Tasman Parakeet, shared with the now-extinct Lord Howe Island version. More commonly however, the Norfolk Island Green Parrot is being considered as its own species, endemic to Norfolk Island, though there is no knowledge as to how long it has been here.
This species originally occurred on Norfolk Island and Phillip Island, though the decimation of Phillip Island by pigs, goats and rabbits would soon have rendered the island useless for the bird. Despite being abundant when Europeans first arrived, it’s habits of eating crops were not found very agreeable and it was easy to control. Having evolved without significant predators, it was barely necessary to shoot, birds being able to be knocked out of the trees. The Lord Howe Island birds didn’t survive this first assault, but the Norfolk Island birds did. For 150 years the bird has teetered on the brink, seemingly getting down to no more than a handful of individuals time and time again, yet just struggling on.
What we have seen though is that, left to its own devices, the bird can recover well. It can rear multiple nests of 4-5 chicks in a year, breed at less than 12 months, and is reasonably long-lived. The establishment of the national park in the 1980’s led to long needed improvement in habitat quality though the issues of predation by cats and rats are more problematic and here for the long-term.
The sexes of green parrots are superficially similar but with practice the larger males can be identified from the females. They feed on a wide range of plants, both native and introduced. Norfolk Island Pine, the endemic Nikau Palm, and the weedy African Olive are just some of their favourite foods. The impact of predators on parrots is increased by the fact that they regularly feed on the ground, especially in winter, where they are more susceptible to attack from cats. Related species in New Zealand and sub-antarctic islands live in quite different habitats, and ground dwelling is a common feature for them also, including for breeding.
Most of the green parrot nests on Norfolk Island occur in low hollows, rarely more than a couple of metres off the ground. I suspect that traditionally the parrots may have bred on the ground here too but the impact of predators, particularly cats, has forced them to move higher for survival.
As recently as three years ago, the parrots were again on the brink, but strong work by the national park and it’s many partners to protect nests and further control cats and rats has led to an astounding recovery in just a short time. The population has grown from under 100 birds in 2013 to 400+ in 2016 and these numbers are borne out by anecdotal evidence around the island. The birds are being seen in places where they haven’t been for generations, I’ve seen them fly over the main street in town!
This has put the birds in an ideal situation for the next phase of their recovery. There is currently a project underway to return the green parrots to Phillip Island, an island that has recovered pretty well since the rabbits were removed and, most importantly, contains no cats and rats. The project is not without its risks but it seems that if it is successful, the birds should thrive over there with no predators. Just how many could live there is hard to estimate, the lack of predators should allow the birds to reach a carrying capacity quickly, but just what that capacity is, who knows?
There is some great habitat there, but also a lot of marginal habitat. There are key food plants that the birds love in New Zealand, such as flax and moo-oo sedge, but on Norfolk Island, where they are essentially rainforest birds, they don’t currently eat them. The big question is how much will they change in what is quite a different environment? While Phillip Island has recovered well, it is generations away from being the rainforest it was before its ‘destruction’. There is also the question of breeding. It will be fascinating to see if they start to breed in the ground again, without the impact of cats and rats. And if they do, will they come into conflict with the petrels and shearwaters already nesting in ground hollows on the island?
More questions than answers at the moment, but a very exciting project and a very exciting time for conservation on Norfolk Island.