Tuesday, 22 December 2015

Green Parrots

A Norfolk Island Green Parrot Cyanoramphus cookii

An almost plain green bird with just a touch of red on its head and blue in its wings might not sound like a stunning beauty, but in the case of the Norfolk Island Green Parrot, this really is an effective colour combination. They are rather endearing.

These birds are not easy to find as they tend to sit quietly in the forest, calling infrequently and softly, which is a pity as their call is the best method of locating them. That was the cue a group of us from Canberra Ornithologists' Club focused on to count Green Parrots while on Norfolk Island recently. We concentrated on listening, then watching for them. The survey was organised by Neil Hermes in collaboration with the Norfolk Island National Park staff, maximising the resource of visiting people-power for a good cause.

These parrots are listed as endangered; their main habitat of native forest is a small area of 465 ha, their breeding is hampered by cats and rats which can catch and eat them or their eggs in their tree hollow nests, they have to compete with the introduced Crimson Rosella Platycercus elegans for nest holes, and the last estimated population, in 2013, was between 42-96 birds. So how many are there now?

A pair of Green Parrots feeding in the forest of Norfolk Island National Park

We set out soon after dawn and stationed ourselves at points along transect lines in the forest of the national park, gradually picking up the birds' calls. Over a few days we found a minimum of about forty birds, and we hadn't covered all the forest, nor included birds at other outlying sites where they were known to have been recently seen. Neil and the park staff will calculate the final count, and it seems that the total will be similar to or perhaps more than that found in the last survey.

The birds' call is certainly distinctive and a clue to their whereabouts, although at first we didn't appreciate just how close we had to be to hear them. Birds in flight were loud and easily spotted, but feeding birds only gave soft contact calls to one another and were not easily heard from more than 100 m away. They are so well concealed in the forest by their green plumage and slow movement that some birds were only seen when directly above or in the body of a bush only a few metres away. On the plus side, such is their confiding nature that once they were found, we were rewarded with fine views of the birds as they nibbled at their food.

A parrot feeds on the unripe berries of Wild Tobacco Soloanum mauritianum a widespread weed,
the berries of which are poisonous to humans, but not birds

The birds I saw feeding were eating a mixture of native and introduced plant species. I watched them delicately pick out fresh shoots from between the prickly leaves of the Norfolk Pine Araucaria heterophylla and pick off the flowers of the Norfolk Island Hibiscus. There are several introduced and naturalised species that they eat and I saw them feeding on Wild Tobacco fruits - they seemed to prefer the unripe green ones - and Willow-leaved Hakea Hakea salicifolia. How they open up those rock-hard fruit casings, I just do not know. Clearly, their diet preferences and abilities are very different from ours.

The parrots also eat the flowers of the Norfolk Island Hibiscus Lagunaria Patersonia
they strip off the petals, throw them aside and eat the ovules at the base of the flower

However, as most of the native forest has been cleared, the birds have lost much of their natural food source and have compensated their diet loss with cultivated fruits and seeds, such as peaches. The parrots were once plentiful across the whole island and neighbouring Phillip Island when the European settlers first arrived in 1788. Then, within 200 years, their numbers were reduced to only about fifteen pairs. The population would have been largely reduced by habitat loss, but many birds were killed over the years, some as agricultural pests.

A parrot eats a peach in a garden 

Times have changed and the island now has a positive attitude towards the parrots; methods have been developed to protect the breeding birds from rats and cats and their numbers have recovered from the low point in the 1980s. If only their habitat wasn't so restrictive, but that is a similar tale for all endangered island endemic species.

Damage to peaches caused by Green Parrots

Those were wonderful times spent with those plain green parrots, I hope to see more of them.

How does one value a rare parrot against a peach crop

1 comment:

  1. Hi Stuart, what a great blog entry. I am very glad that you got to see these birds during your visit to Norfolk Island. The numbers are up, from my original 2013 estimate. Over three years we have found that numbers dwindle particularly after Autumn/Winter. Then as more juveniles fledge, numbers are up once again. Our Conservation Campaign for the Green Parrot (Norfolk Island National Parks, Massey University, Flora and Fauna Society, World Parrot Trust) continues and next year a group of these birds will be translocated to Phillip Island, applying techniques developed for closely related species during my PhD studies. Stay tuned for developments on the conservation of these lovely birds. All the best
    Dr. Luis Ortiz-Catedral/Massey University