Friday, 11 December 2015

Some birds of Norfolk Island

A Masked Booby Sula dactylatra tasmani flies past a Norfolk Pine

Last week I was out on Norfolk Island, which lies at 29 degrees south, about 1400 km east of the Australian mainland and 750 km from the northern tip of New Zealand. I was with other members of the Canberra Ornithologists' Group on a bird surveying trip organised by Neil Hermes. The main surveys were of the endemic and endangered Norfolk Island Green Parrot Cyanoramphus cookii, and all birds on the adjacent Phillip Island which is slowly becoming re-vegetated following extensive denuding by pigs, goats and rabbits in the past. There are none of these on the island now, since the eradication of rabbits in the 1980s. I will post more on these topics later, this page is simply an introduction to the island's wildlife, and I'll post a page on the history of the island on ByMyEy.

The view south from Mount Pitt, with  Norfolk Pines Araucaria heterophylla in the foreground
and Nepean and Phillip Islands in the distance.

The highest point on the island is Mt Bates at 319 m and the area is 35 sq km. Most of the island is worked by small holdings growing fruit, vegetables and cattle, milk and beef, and the main income is currently tourism, serviced by flights into the airport which dominates the centre of the island. The island was once covered by rain forest dominated by tall stands of Norfolk Pines and Norfolk Island Palms Rhopalostylis baueri the best examples of which now grow in the National Park, centred around Mt Bates

A male Pacific Robin Petroica multicolor multicolor - the most colourful of the forest birds

The endemic forest birds are largely restricted to the remnant stands of the forest, while numerous introduced species populate the town, gardens and farmland and are much more obvious. House Sparrow, Starling, Greenfinch and Rock Dove are limited to these areas, but Eurasian Blackbirds, Song Thrush and the Australian Crimson Rosella are all common there and in the forest. There is even a population of feral Jungle Fowl, descendants of escaped or released domestic chickens. The various combinations of bird species that occur on different islands worldwide is fascinating, but can be threatening to their endemics, especially on small islands such as Norfolk which has already lost seven, probably now eight species.

A Grey Fantail Rhipidura albiscapa pelzelni - one of the seven forest birds unique to the island

The other main natural habitats on the island are the coastal cliffs and shores. The cliffs gird most of the coast and there are plenty of good vantage points to watch the seabirds as they glide along on the wind. There are a boulder beaches at the base of some cliffs, but they are poor for birdlife. However, the small coral reef and sandy beaches at Kingston attract migrant waders such as Ruddy Turnstone, Pacific Golden Plover and Whimbrel.

Two Sooty Terns Sterna fuscata fly overhead - mostly seen around the coasts but they fly over any part of the island at times

The whole island ecology is driven by the rich volcanic rock and the derivative soils, much of which have been enriched by the leaf litter from the forest as it developed, and by the guano of the seabirds as they brought in nutrients from the sea. All sprinkled with a splash of water carried by the winds. So, to me there was no surprise that the most vibrant birdlife was in the forests and on the sea-cliffs. One set was secluded in shade, the other basked in blue skies.

A Red-tailed Tropicbird Phaethon rubricauda a common sight along the sea cliff tops.

No comments:

Post a Comment