Southwestern snake-necked turtles on the move

As the native turtles living around our lakes and wetlands begin to migrate and nest, the City of Cockburn is encouraging the community to learn how to help keep the ‘near threatened’ freshwater reptiles safe.

The semi-aquatic Southwestern snake-necked turtle (Chelodina oblonga – prev. C. colliei) is the focus of concerted ongoing annual efforts by the City to reduce mortality rates particularly at Bibra Lake, Yangebup Lake, Harmony Lake, Blue Boy Lake, Market Garden Swamp and Manning Lake which support active populations.

The turtles are most at risk as they start to leave the water to move between lakes during migration, usually in winter as rain replenishes groundwater levels, and as females seek sandy locations to lay their eggs between late September and early February, generally peaking during October.

Hatchlings are also on the move anytime between March and September as they break free of their eggs and shallow soil nests to head for the relative safety of water.

This year the City will hold free turtle information sessions on Saturday 4 September at 2.30pm, and Thursday 9 September 6.30pm, with online registration essential.

City-backed Murdoch University PhD Candidate Anthony Santoro and WA Wildlife specialists with resident turtle Tommy, will join the City’s Environmental Education Team to increase awareness of the iconic turtles and how City programs promote their conservation.

City of Cockburn Acting Head of Sustainability and Environment Chris Beaton said concerted efforts over many years would be needed to help local populations survive and thrive in the long term.

“This year the City is supporting two Murdoch University School of Environmental and Conservation Sciences Honours students researching egg incubation (ideal hatching conditions) and monitoring fauna underpasses,” Mr Beaton said.

“This builds on the previous valuable work of Murdoch PhD Candidate Anthony Santoro who has been instrumental in researching our turtles and designing and implementing the successful Turtle Trackers citizen science program.”

Mr Santoro, who is now completing his thesis, said the Turtle Trackers program had resulted in about 25 nests being protected in each of the past two nesting seasons.

“There was an average of 10 eggs in each nest, a minimum of seven and a maximum of 17. We also saw reductions in the number of females killed on roads,” Mr Santoro said.

“The data gained through Turtle Trackers suggests female turtles appear to be triggered to nest by weather patterns consistent with cold fronts.

“This includes dropping barometric pressure, increasing humidity, and relatively warm days prior to the front passing. However, due to climate change, the fronts don’t always result in the rainfall that was historically associated with them.

“We are continuing vital research on the species and have recently started two projects. One aims to determine optimal hatching conditions for future breeding/head-starting programs, while the other is trialling underpass designs to maximise their use by migrating turtles and reducing road mortality.”

Last week’s extensive rain prompted the migration of turtles back to their home wetlands and seven were taken to WA Wildlife’s Bibra Lake HQ after being found by residents.

Mr Beaton said the turtles included a hatchling and adult males, with four surviving the ordeal.

“These turtles had suffered raven attack or lacerations or crush injuries consistent with vehicle strike. Along with fox, dog or cat attack, these are the main cause of injury and death for turtles as they come out of the water to travel between water bodies or nest.”

The City has placed signage around local lakes where migrating turtles have been spotted and other signage will be deployed as needed.

The City has already undertaken fox control, with more planned for September and a team of trained volunteer Turtle Trackers will be mobilised to provide protection for nesting females.

What is the City doing to help protect nesting females during the 2021-22 season:

Conducting feral animal control in and around turtle nesting areas in conjunction with the Department of Biodiversity, Conservation and Attractions Installing temporary educational signage – ‘turtles on the move’, ‘keep dogs on-leash’ and ‘slow down for turtles’ Implementing the Turtle Trackers program to help protect turtle nests at Bibra Lake Collaborating with Murdoch University to deliver turtle, egg and fauna underpass monitoring Researching the feasibility of installing a specially designed fauna underpass on Progress Drive Maintaining 12 lakeside nesting refuges at Bibra Lake Installing traffic education message boards Visit the City’s website to register to attend the 4 September opens in a new windowand 9 September  opens in a new windowinformation sessions. Visit the City’s Turtle webpage  opens in a new windowto find out more about the local species.

Caption: l-r Murdoch University Honours students Zoe Regan and April Sturm with the City’s Vicky Hartill, Alex Patmore and Tommy the Turtle from WA Wildlife and Murdoch University PhD Candidate Anthony Santoro.