Extract from ABC News
In short:
Researchers have mapped the changing fortunes and presence of Australian brush turkeys from pre-1900 to 2019.
An analysis of historical and modern records shows how the native species has gone from near-extinction to entrenched urban bird.
What's next?
More citizen science contributions will fuel further research into how big urban populations could become.
When David Poole was a kid, knocking around the bushlands of Sydney's northern suburbs in the late 1970s, there was not a brush turkey to be seen.
But a few years ago he began to notice the black plumage, bald red head and yellow dangling wattle of the native bird around his streets.
"It wasn't until I was in my 50s that I noticed them encroaching into suburban areas where they are now prolific," Mr Poole said.
"[They're] non-aggressive but very destructive to gardens, regularly open garbage bins and spread garbage across the road ... [and] often on the roads causing a driving hazard as they are not afraid of cars."
The Australian brush turkey's (Alectura lathami) colonisation of the city has seen it take over the northern suburbs of Sydney, and more recently start a push into the inner-west, south of Darling Harbour and the Parramatta River.
Remarkably, the brush turkey — also known as the scrub turkey — has gone from a creature we feared was on the brink of extinction in the 1930s to a fully fledged urban bird.
Now a new study published in the Australian peer-reviewed journal Wildlife Research has chronicled the fall, rise and conquering of Brisbane and Sydney by a bird we nearly ate to extinction.
An analysis of historical museum specimens, birdwatching logs, archival newspapers and more modern sources such as citizen science contributions to the Big City Bird digital app resulted in a collection of close to 100,000 records of the bird from 1839 to 2019.
Lead author Matthew Hall, who is an urban ecologist at the University of Sydney, said the brush turkey was once common throughout Queensland and New South Wales.
"They got as far south as the border with Victoria and as far west as Dubbo, maybe even further.
"They've actually disappeared from a lot of those places now.
"We think they originally disappeared by the early 20th century because of over hunting."
Anecdotally, the bird went from being a common sight on the landscape to so few in number that, in 1952, the New South Wales government set out to survey where the brush turkey and the inland Australian bustard, also known as the plains turkey, might have survived.
Legislation changes in the 1970s mean native species, including the brush turkey, were suddenly protected.
And in a rebound that bears similarities to the recovery of salt water crocodiles in northern Australia, Dr Hall said legal protection helped the turkey return from the brink.
The authors of the study admit the quality of records prior to a national bird survey in 1977 are lacking, so turkey population numbers before then were probably underestimated.
But Dr Hall said the first resighting of the bird around a capital city was in Brisbane in the mid-1970s.
Brush turkeys started to radiate from around Mount Coot-Tha, a large forested area bordering Brisbane's west, into neighbouring suburbs quickly.
A 1991 study noted turkeys were present in about 39 of the River City's suburbs.
That figure has since jumped to 158 suburbs.
Sydney's brush turkeys started showing up in the Central Coast in the 1980s and 1990s, Dr Hall says, "then became really common in northern Sydney in the 2000s and 2010s".
In 1999, a mere four Sydney suburbs recorded turkeys.
Nearly three decades later, they are in 312 suburbs.
Why the rapid colonisation?
Legal protection and urban greening are two hypotheses for the turkeys' re-emergence and subsequent takeover of cities.
That and the turkey's own adaptation to big-city living.
"They'll eat almost anything they come across," Dr Hall said.
"So they've taken really well to scavenging off any food they can find in the city.
"They've also learned to build their nest out of somewhat sub-optimal materials."
Male turkeys build large mounds in which females lay their eggs.
During the annual breeding season, a female can lay about 20 eggs and more than one clutch can be laid in a single mound.
Despite predation by cats and foxes, enough baby turkeys survive each season to keep population numbers rising.
Dr Hall said urban turkey numbers could really explode if cat curfews were put in place.
He noted further research was needed to understand what environmental factors might put a cap on population numbers.
"One of their limits ... is the number of available roosting trees, but I've seen at least 70 brush turkeys all roosting in a single tree so they can get to really high densities in some suburban areas," he said.
"They've lost some of that territoriality ... so they're not driving each other out."
But whether they're in a coastal rainforest or busy food court, it seems the new generation of east coast Australians won't remember a time without turkeys.
And that's something Dr Hall hopes people remember if they ever start feeling annoyed about their neighbourhood turkeys.
"They're actually a fantastic success story of a pretty unique native species that's come back from possibly the brink of extinction and is now thriving in one of the most hostile environments we can make for them," he said.
"We're probably very lucky that bird like the brush turkey is able to survive, and in an urban environment."
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