If you happened to be tromping through the grassy woodlands of eastern Australia in the year 1927, you might have been lucky enough to come across a remarkably colorful parrot, even by parrot standards. The paradise parrot, as it was then known, was a medium-sized parrot with a long tail and a radiant plumage of turquoise, aqua, scarlet, black and brown.
Regrettably, if you were taking that same walk a year later, your chances of seeing a paradise parrot would be effectively zero, as no live birds were spotted after that date, despite extensive and sustained searches.
Fortunately, the paradise parrot is the only mainland Australian bird species that has been lost since Europeans colonized the island continent in 1788. New research published in Austral Ornithology attempts to understand why.
“The extinction of only one bird species (paradise parrot, Psephotellus pulcherrimus) from the Australian mainland contrasts with the far higher rate of extinctions of Australian mammals,” state the researchers, led by John Woinarski of Charles Darwin University.
It also contrasts with higher rates of bird extinctions on the island territories of Australia, such as Lord Howe Island, Macquarie Island, Norfolk Island and King Island. All told, there have been eight documented bird extinctions in island regions of Australia (not counting Tasmania).
“The first bird extinction subsequent to European colonization was the loss of the flightless white gallinule from Lord Howe Island over the period 1788–1790,” state the authors. “Extinctions have occurred in most decades since then, with the most recent being for Norfolk Island’s white-chested white-eye in the decade 2000–2009.”
Island birds, according to the authors, are more susceptible to extinction for a number of reasons–but primarily because they have smaller populations to begin with and inhabit smaller geographical ranges. Hunting by humans is the most common cause of extinction.
“The impact of hunting was especially pronounced on island endemic species as many of the affected birds were predator-naive, flightless, and had small population sizes–and were sufficiently large to provide a substantial enough food resource to encourage hunting,” write the researchers.
In recent decades, successful environmental protection policies have stanched the impact of hunting on bird population declines in Australia, but significant threats remain. Loss of habitat, climate change and its manifold effects (e.g., increasing wildfires) and the continued introduction of invasive species all make it likely that bird extinctions will continue to accrue over the next several decades. Other research suggests there is a greater than 75% likelihood of extinction in the next two decades for four bird Australian bird species: the King Island brown thornbill, the orange-bellied parrot, King Island scrubtit and the western ground parrot.
Nevertheless, Australian bird fauna is faring better than conspecifics in other parts of the world. For instance, New Zealand has lost 17 bird species over the same period, while having a fewer overall number of bird species.
And, comparing bird and mammalian extinction in Australia, the authors write, “Whereas nine Australian bird species (1.2% of the Australian bird species) have become extinct, of which only one occurred on mainland Australia, 33 Australian mammal species have become extinct (about 10% of the complement of the Australian terrestrial mammal fauna).”
It goes without saying that we need to do everything we can to preserve Australia’s precious aerial fauna–hopefully keeping the paradise parrot alone with the regrettable moniker of “Australia’s only lost bird species.”
“As ornithologists, we deeply regret that we now have no opportunity to see the beautiful paradise parrot or the quirky white gallinule. We should not rob our children of the opportunity to see what exists now. [...] We can, and must, do better,” conclude the authors.