Australia is home to a rich and diverse avian fauna, with over 750 native bird species inhabiting its vast and varied landscapes. However, not all birds are equally fortunate.
A recent study led by Dr. George Olah from The Australian National University reveals a worrying trend: island-dwelling bird species are more likely to face extinction than their mainland counterparts.
The study, published in Emu-Austral Ornithology, identifies several characteristics that increase the vulnerability of certain Australian birds.
These include being endemic to a single island or archipelago, having a small population size, being flightless or ground-dwelling, and being threatened by invasive predators or habitat loss.
The researchers also found that island birds are more prone to genetic drift and inbreeding, which can reduce their adaptability and resilience.
Why Islands Matter for Bird Conservation(Photo : SAEED KHAN/AFP via Getty Images)
Islands are important habitats for many bird species, as they offer unique ecological niches, lower competition, and higher speciation rates.
However, islands also pose significant challenges for bird survival, as they are often isolated, fragmented, and exposed to environmental fluctuations and human disturbances.
According to the study, Australia has 8,222 islands, covering 8.6% of its land area. These islands host 14% of Australia's bird species, of which 45% are endemic to one or more islands.
However, these island birds are also disproportionately threatened: 35% of them are listed as extinct, endangered, or vulnerable, compared to 10% of mainland birds.
The study highlights the need for urgent and targeted conservation actions to protect Australia's island birds, as they represent a valuable and irreplaceable part of the country's natural heritage.
The researchers suggest that some of the most effective measures include eradicating or controlling invasive species, restoring and expanding native habitats, monitoring and managing populations, and increasing public awareness and engagement.
How to Save Australia's Island Birds from Extinction
The study also provides some examples of successful conservation initiatives that have helped to prevent or reverse the decline of some island bird species. These include:
The recovery of the Lord Howe woodhen, a flightless rail that lives on Lord Howe Island, a World Heritage Site in the Tasman Sea.The woodhen was once abundant on the island, but its population plummeted to less than 30 individuals by the 1970s, due to predation by introduced pigs, cats, and rats, and habitat degradation by cattle and weeds. A comprehensive conservation program, involving captive breeding, predator control, habitat restoration, and community involvement, was launched in 1979, and resulted in the woodhen's population rebounding to over 300 birds by 2003. The woodhen is now classified as vulnerable, rather than critically endangered.
The translocation of the noisy scrub-bird, a secretive and vocal songbird that lives in dense understorey vegetation in southwestern Australia. The scrub-bird was thought to be extinct until it was rediscovered in 1961 in a small patch of forest near Albany. The scrub-bird's habitat was severely fragmented and degraded by logging, clearing, and fires, and its population was estimated at less than 500 birds by the 1980s. A translocation program, involving the capture and release of scrub-birds to suitable sites within and outside their original range, was initiated in 1983, and resulted in the establishment of several new populations and the expansion of the scrub-bird's distribution. The scrub-bird is now classified as endangered, rather than critically endangered.
The reintroduction of the Norfolk Island green parrot, a colorful and charismatic parrot that lives on Norfolk Island, a subtropical island in the Pacific Ocean. The green parrot was once widespread and abundant on the island, but its population declined drastically due to hunting, habitat loss, and predation by introduced cats, rats, and crimson rosellas. The green parrot was on the verge of extinction by the 1980s, with only a few dozen birds remaining in a small area of the island's national park. A reintroduction program, involving the captive breeding, release, and monitoring of green parrots, as well as the control of predators and competitors, was implemented in 1986, and resulted in the green parrot's population increasing to over 400 birds by 2019. The green parrot is now classified as endangered, rather than critically endangered.
These success stories demonstrate that it is possible to save Australia's island birds from extinction, if there is enough political will, scientific knowledge, and public support.
However, the study also warns that there is no room for complacency, as many island bird species are still facing imminent threats and require immediate intervention.
The study urges the Australian government and the international community to recognize the value and vulnerability of island birds, and to allocate more resources and attention to their conservation.
