Native wildlife efficiently reclaims territory from launched rodents in Sydney

Australian Wildlife Conservancy

In the battle between native wildlife and introduced intruders, native species win at the North Head Sanctuary in Sydney, where Australia’s tiny bush rats are successfully reclaiming their territory from gangs of invasive black rats.

Results from recent wildlife surveys showed that North Head’s black rat population declined from an estimated 112 in 2019 to 29 in 2020. The decline continued in May 2021 when only eight black rats were caught during an investigation of 250 hectares on the island. Australian Wildlife Conservancy offers conservation science projects, including surveying work like this one at the North Head Sanctuary, administered by the Sydney Harbor Federation Trust. The significant decline in black rats is directly related to the reintroduction of 170 bush rats between 2014 and 2016 that were released as part of a unique initiative to use native wildlife to displace an alien species and act as a biological control.

Australia’s bush ratsare territorial. If they gain strength in numbers, they can fend off competitors and reclaim their land from seemingly stronger species like the black rats. In North Head, the reintroduction of this native species after the number of black rats has been reduced is blocking re-invasion by introduced rodents.

“Bush rats and black rats can fall under the same rodent category, but they have different environmental impacts. Bush rats are native and support the local ecosystem by pollinating local trees and flowers to the tip of each plant, ”said Viyanna Leo, wildlife ecologist at the Australian Wildlife Conservancy. “Bush rats coexist with other native species and their presence prevents harmful species such as black rats from eating the eggs of endangered bottom-dwelling mammals and birds.”

“It’s very exciting that this native wildlife reintroduction initiative to eradicate pests has worked and has a track record of reclaiming their territory from an invasive species.”

Daniel Sealey, Director of Planning at the Harbor Trust, said protecting the endangered flora and fauna at the North Head Sanctuary was a top priority for the Harbor Trust.

“It is very gratifying to see the numbers of native wildlife continue to grow as these endangered species have their presence in North Head thanks to the Australian Wildlife Conservancy, which has worked with the Harbor Trust to reintroduce these species to this site further consolidate. ”said.

Wildlife surveys at the North Head Wildlife Sanctuary in May 2021 also found that small mammal populations remained strong despite a mitigation burn that broke containment lines and destroyed 57 acres of the headland in October 2020. Australian Wildlife Conservancy was not involved in the incineration.

Four brown antechinus were discovered in Elliott traps during the investigation – the highest number of live catches since the species was reintroduced to the reserve in 2018. Ecologists believe that fires may have displaced individuals from their usual habitat, causing them to move in to seek shelter in the vicinity of the study area. Twelve eastern pygmy possums have also been registered, including five new individuals and five females with pouch young, suggesting that they can reproduce and develop well after the fire.

Australian Wildlife Conservancy (AWC) is Australia’s largest private (not-for-profit) conservation organization protecting endangered wildlife with a unique science-based land management and partnership model. AWC is a national leader in landscaping, reintroducing threatened species, and establishing wildcat and fox-free areas.

/ Public release. This material comes from the original organization and can be punctiform, edited for clarity, style and length. View in full here.