The ghost birds of Norfolk Island
WITH ITS CONVICT ruins and connections to the HMS Bounty saga, Norfolk Island is perfectly suited to ghost stories. When I visited in 2009 shearwaters crooned over the ruined ramparts of the Norfolk Island prison; a reminder of times past, when this small 34.6 km² South Pacific island heaved with incredible numbers of seabirds and a rich endemic birdlife.
Since Cook first sighted the island in 1774, a total of four endemic bird species and five subspecies have become extinct. Among the losses were the Norfolk Island kaka and pigeon, which were so common when members of the First Fleet landed in 1788 that they described them as pests. The kaka, a separate species to the New Zealand parrot, only survived until the early 1800s and the pigeon, a subspecies of the New Zealand pigeon, until 1901.
Norfolk and Lord Howe Islands have by far the worst record of bird extinctions in Australia, which continues to this day. The kaka and pigeon were exterminated by hunting and forest loss, but the latest wave of extinctions has been largely from rats and cats. The last island thrush (guavabird) was seen in the 1970s and the white-chested white-eye is on the verge of extinction.
In 2009, I spent three weeks surveying Norfolk for the white-chested white-eye. Initially, I was concerned at how little native forest remains, but encouraged at the abundance of many forest birds. The last survey mapped only 172 ha of native vegetation, but this is buffered by a larger area of weedy forest that is slowly being rehabilitated back to native species. Walking along the trails, I was delighted to see so many Norfolk Island gerygones, which are quite tolerant of degraded forest.
Surveying bird species
TO SURVEY FOR the white-chested white-eye, I would cycle every morning up to the national park. Norfolk is a small island but remarkably hilly, so cycling up to the forest pre-dawn was an effective coffee substitute. Norfolk is blessed with three white-eye species, and my eye was soon attuned to distinguishing the endemic slender-billed white-eye from the familiar silvereye. Slender-bills were pleasingly common, and also had a population of about 4000 in the park. As often happens with birds on species-poor islands, they have expanded their ecological niche beyond that shown by continental white-eyes, and family groups often crept along branches, investigating underneath, like sittellas.
Although happy to find so many of this endearing endemic, the white-chested white-eye soon became my holy grail. It was common in 1909, but already very rare by 1969 when white-eye expert G.F. Mees only saw them three times in a two-week survey. Several were seen on a Royal Australasian Ornithologists Union (RAOU) survey in 1979, and since then there has been a trickle of sightings, including two reported in a 2005 bird survey. The species has, however, never been photographed or sound-recorded and is even less well-known than the night parrot, that other great ‘ghost bird’ of Australian ornithology.
Norfolk birds
BEFORE DAWN, ALL would be quiet until the Pacific robins started singing. For a brief quarter-hour the forest was all robins; then they were drowned out by the golden whistlers. Norfolk whistlers are a distinctive subspecies in which males look identical to females and will surely be split as full species in taxonomic revisions to come. They are incredibly confiding, earning the local name of tamey, an echo of the days before Norfolk had people, cats or rats, and when birds were naively tame.
Once it was light enough to survey birds, I walked along the grids of rat-bait stations that are maintained to minimise the impact of introduced rats. At each station, I recorded all birds within 20m and used their distance from my position to calculate their population densities. This worked well for active and vocal species, less well for quite cryptic species, and not at all well for Pacific robins, which would fly in to check me out, resulting in many close observations biasing my estimate of their population density.
Alongside the endemic species, Norfolk has a handful of more widespread birds—of Australian rather than New Zealand affinities—including grey fantails and a suite of introduced birds. The large numbers of blackbirds throughout the forest may have been a reason for the demise of the island thrush. My surveys suggested that numbers of feral chickens and crimson rosellas were increasing. Crimson rosellas compete with the Norfolk Island (Tasman) parakeets for the few remaining nest holes and nest boxes.
Thanks to the work of islanders and national park staff—who have been creating new nesting hollows and trapping rats and cats — today the ‘green parrots’, as they are locally known, are a conservation success story with an estimated population of over 200 birds. This is one of 34 species worldwide that have improved their threat status as a result of conservation work; a clear message to refute those who believe that species recovery is too hard.
Some evenings I searched the forest again, and then sat atop Mount Bates, overlooking the whole island from a steep 319 m above the sea, and waiting for Norfolk’s other rarest bird, the Norfolk boobook (or morepork). The owl is a conservation half-success. There were no suitable hollows within which it could nest, and its population crashed to one individual until a New Zealand morepork was introduced. Now the Norfolk nights resound again to their progeny crying out for more pork. On other evenings, I sat on clifftops watching seabirds and sunsets. Wedge-tailed shearwaters and black-winged petrels swept over the cliffs in numbers large enough to excite most birdwatchers, but were a tiny fraction of the island’s historical seabird population.
Pests and protecting birds
Sirius was wrecked on Norfolk Island and 270 extra people joined the few first settlers. There were not enough supplies to feed them all but they soon discovered that by lighting fires at dusk, a type of petrel would “drop down out of the air as fast as the people can take them up and kill them”. They took 2000–3000 birds every night for two months and named it the bird of providence. Not long after, the providence petrel became extinct on Norfolk Island, and now survives only on Lord Howe Island with a handful on Phillip Island.
The other shearwaters and petrels survive in greatly reduced numbers on Norfolk Island. Cats predate a large proportion of the burrow-nesting seabirds despite the best efforts of the islanders to control cat numbers. Phillip Island, 7 km to the south, has no permanent water and was never settled; but pigs, goats and rabbits were introduced to give the prison governors the option of going hunting on Sundays. After the last penal settlement was abandoned, these mammals ate the island down to a virtual desert, with just a handful of trees remaining. The last rabbit was finally eradicated in 1986 and vegetation is returning to Phillip Island, which now supports 13 seabird species. This is one of the most important seabird sites in Australia, and is an Important Bird Area (IBA) for its seabirds, as Norfolk Island is an IBA for its threatened and endemic birds.
Phillip Island’s seabirds need far more attention, however. We know very little about their population sizes, trends and breeding success. And, much revegetation and weeding work remains to be done. Nesting masked (or Tasman) boobies are scattered across the island, and the air is full of sooty terns and black noddies. Phillip Island is transformed at night when the petrels and shearwaters return to court in the skies and flirt outside their burrows — a happy sign that cats and rats are absent. A handful of pairs of white-necked petrels breed, but the spring nights belong to the black-winged petrels. The deafening aerial chattering of courting petrels, and the occasional thump as they hit unsuspecting birdwatchers, is a reminder of how Norfolk Island used to be.
Back on Norfolk Island, I found no evidence of the white-chested white-eye and propose that it should be listed as Possibly Extinct, a BirdLife International and IUCN category that means don’t give up on it just yet. There are very few resident birdwatchers on Norfolk Island, and all visitors are encouraged to look for the white-eye. Otherwise, it will have to be added to the list of Norfolk Island’s extinct birds. If this is the case, let us hope that this is the very last extinction to befall the island; the final legacy from the colonial penal era.
Guy’s fieldwork was sponsored by BirdLife International / British Birdwatching Fair, RSPB and supported by Parks Australia and the Norfolk Island Flora and Fauna Society.
This is an edited version of an article first published in the Birds Australia magazine, Wingspan. Guy Dutson managed Birds Australia’s Important Bird Areas program and has written a forthcoming guide to the birds of Melanesia.
Editor’s note: since this article was written the white-chested white-eye has now beem officially recorded as extinct.
