Christmas Island Red-Tailed Bird Soon to Join Vulnerable List with Only 3,000 Left in Australia

Given that only a little over 3,000 of these birds remain in Australia, according to recent surveys, the red-tailed bird found on Christmas Island may soon be added to the IUCN's list of threatened species.

With their elongated tails streaming in the sea breeze, the cartwheeling Christmas Island tropicbirds have been a permanent fixture in the northern Australian skies of the Indian Ocean for a long time.

Only a Little Over 3,000 Left

The red-tailed tropicbird, also known as the silver bosun, has been subjected to the scrutiny of the threatened species commission due to a sharp decline in its population.

An estimated 3,350 people are still alive, which represents a 36% population decline over 30 years and is primarily a result of cat and rat predation.

Silver Bosun and Golden Bosun

The enormous streamers on the silver bosun's tail, also known as its most distinctive feature, can extend 35 centimeters behind the bird's length, which can reach about one meter.

Christmas Island, an Australian territory located about 1,550 kilometers off the coast of Exmouth in Western Australia, is home to the majority of the bird's population. Additionally, Ashmore Reef, Rowley Shoals, and the Cocos (Keeling) Islands are home to the bird.

At Sugarloaf Rock in the southwest and the Houtman Abrolhos islands located off the mid-west coast, the silver bosun hasn't bred in the last three decades.

The "golden morph" of the White-tailed tropic bird, which is endemic to Christmas Island, is referred to as the golden bosun. The golden bosun is known to only breed on Christmas Island, where its feathers have a gold tint, giving rise to its local name. Overlooking the Indian Ocean, it nests and forages. This priceless bird is classified as endangered and there are fewer than 10,000 of them left, National Park Conservation Trust reports.

Every year, about 80,000 seabirds nest on Christmas Island, which also supports several land-based species, including endemic ones that are unique to the island.

Cats, Rats, Ants... and Yes, Climate Change

Threats to the bird, according to Fiona Fraser, the commissioner for threatened species, include cats, rats, and yellow crazy ants.

Fraser continued by saying that the impacts on the birds are extensive. Most likely, there have already been some effects of climate change, and more are likely to come in the future.

This occurs both directly and indirectly as a result of cyclones occurring more frequently, which may affect the nesting habitat and the accessibility of food sources.

No Cat's Land by 2025

On Christmas Island, feral cats are to blame for the recent decline or extinction of some species.

Forest skinks, which until the 1990s were widespread on the island, are now extinct, and the last one was known to have perished in captivity in 2014.

Similarly to that, the Christmas Island pipistrelle, a tiny bat, went extinct in 2009, making it the first Australian mammal to be confirmed extinct in 50 years, according to Monagbay.

More than 1,000 cats have been eliminated from the island since 2015, and the mission to eradicate all cats by 2025 is still in place. But purging the isolated island of cats is no simple task given its rugged limestone topography and dense forests. Fraser claimed that it would be challenging to get rid of the last few cats because they have become extremely accustomed to Christmas Island's dense vegetation.

Techniques and Concerns

According to Fraser, the various tropicbird species have already benefited from the current cat and crazy ant controls.

For a cat eradication program, Parks Australia was given over $4 million in funding last year.

According to a Parks Australia spokesperson, this program, which started in July 2021, is producing excellent results by using cutting-edge methods to catch the remaining feral cats, such as sophisticated grooming traps and thermal imaging at night.

The program will continue to be actively reviewed as it moves forward, with 2025 as the current set deadline for eradication set by Parks Australia.

The removal of cats had previously raised concerns about a potential increase in rat populations. Red crabs can sometimes be competing with or even preying on rats to keep populations low, according to research, which also revealed that rat density was lower on this island than on other islands, ABC News reports.