The Baskerville case
Norfolk Island’s chickens
By December 2011
There are several things an astute observer will notice on arriving to Norfolk Island. First, the island’s eponymous pine trees, which rise up like oversized pins marking important spots on a map. Second, a world-heritage listed collection of Georgian buildings, some of Australia’s oldest and best preserved, which stand as testament to the first and second British settlements established on the island in 1788 and 1825 respectively. And third, random and numerous broods of feral chickens, who spend their days scratching and pecking against a variety of the island’s picturesque backdrops – in lanes and culverts, in the Norfolk Island National Park and Botanic Garden, and among its magnificent convict-era buildings and ruins.
When Bruce Baskerville arrived on the island in 2008 as site manager for those buildings and ruins, the chickens reminded him of wild chickens he’d seen in Malaysia. “I’d had chooks before, so I’m interested in them,” he says, “and I knew a lot of people who bred heritage and endangered species. The island’s chickens didn’t look like ordinary domestic fowls – they looked like something else.”
This got him thinking about the island’s history. “The First Fleet stopped in both Rio and Cape Town on its way to New South Wales, and in both places chickens were brought onboard not just for eggs and food as the fleet sailed, but also because they were coming to found colonies, as breeding stock.” The fleet’s second colony, instigated less than two months after the establishment of Sydney, was on Norfolk Island.
The Pier Store Museum, abutting the island’s wharf at Kingston, holds an impressive array of First Fleet artefacts – the fleet’s flagship, HMS Sirius, went down just offshore in 1790, and quantities of objects, from its vast anchors and carronades down to spigots, staples and nearly 4000 sheathing nails, have been subsequently recovered and restored. Baskerville wondered if the chickens were another First Fleet artefact, left behind when the island was abandoned in 1813, and thus the bearers of a distinct genetic lineage. He contacted Dr Jaime Gongora, a senior lecturer in conservation and animal genetics at the University of Sydney, about this possibility, and together they designed a research question for an honours student, Shannan Langford Salisbury.
“Jaime said I might get to go over to the island,” she says, “and I thought that sounded pretty good – for an honours project. In the end, Bruce couldn’t get samples from the island’s chickens, so I did have to go and get them myself.” She extracted DNA from 25 chickens – using blood drawn from a vein just under their wings – to compare with samples from both Australia and the rest of the world.
“I thought the chickens might be held in higher regard if they proved to be something special,” Baskerville says, “you know, artefacts of the First Fleet, distinct genetic stock, of scientific importance.” If the importance of their cultural heritage could be determined, it might also afford them protection under the Australian Natural Heritage Charter.
Norfolk Island’s chickens are not universally adored. “The question is whether you see them as having angels’ wings or devils’ horns,” laughs Coral Rowston, park manager of the island’s National Park. “From our perspective, they’ve got devils’ horns.” The chickens dig up the ground and leaf litter in the park and botanic garden, and they dig up the woodchips that line the island’s walking tracks. They uproot seedlings – particularly endemic ones vital to bush regeneration work. And they eat some things that the Park’s people would prefer they didn’t.
“We don’t know their full diet,” says Rowston, “but we have five critically endangered snail species here: if they came across those, they would eat them.” The habitat of one snail – Mathewsoconcha suteri – is “litter, woodland”, which may put them in the way of peckish fowl. “In the larger scheme of things, the chickens are an introduced pest species, regardless of their genetic heritage.”
Norfolk Island National Park has an active chicken-control scheme: over 50 chickens were removed in 2008–09, and again in 2009–10, according to its annual reports. But Rowston estimates that the total population might run into the thousands across the 8 kilometre by 5 kilometre island. “The senior residents here say the numbers are certainly much higher now than they were 30 or 40 years ago,” says Baskerville.
Oral histories also suggest that the older feral population has been augmented by more recent arrivals. “Islanders referred to ‘old-type’ chickens,” says Salisbury, “black hens with gold necks, and a little bit of blue-green across their backs – they resemble some European breeds,” she says. “But I saw other ferals while I was there that I could recognise as other contemporary domestic breeds.”
The ancestry of most modern chickens can be traced back to wild red junglefowl from South-East Asia and the Indian subcontinent – some of their genetic signatures are now ubiquitous throughout India, the Middle East, Europe, China and Africa, making it difficult to assess the origin of particular chicken specimens. However, as earlier work by Gongora on Chilean chickens has revealed, some contemporary chickens from Indonesia, Japan and China do share a distinct genetic profile with some pre-European – or ‘ancient’ – chickens in the Pacific, and this may indicate an earlier dispersal of the birds throughout Polynesia.
In the context of this, says Gongora, “the level of genetic differentiation both within the island’s chickens and between these ferals and chickens from across the world is within a normal level of divergence.” There does not appear to be a distinct ‘First Fleet’ population. But some of the genetic profiles revealed in Salisbury’s work on the island are interesting, and may help to unravel the impact those earlier ‘ancient’ Pacific chickens might have made to Norfolk’s feral population. Gongora’s team is now investigating these findings.
From Rowston’s point of view, the inconclusive results are “good for us” – the Park’s chicken-control program can go on. From Baskerville’s, interest in Norfolk Island’s chickens from some mainland heritage breeders, who saw similarities between pictures of the island’s ferals and their own birds, at least suggests that the whole thing “wasn’t a wild-goose chase”.
And from the point of view of the chickens, tomorrow’s just another day of free-range pecking and scratching in an idyllic, subtropical setting.