Singing Bats

"Bats are famous for producing sounds that help them orient themselves in the night sky and zero in on insects to munch upon. These are known as echolocation.”

But researchers have found some bats also make other trilling or chirping sounds for other purposes. For example, silver-haired bats in British Columbia, Canada, have been recorded singing to each other. The sounds had to be brought into the human range of hearing to be heard.

It is thought that the songs, which sound like bird song, are used to attract mates.

Refs: Jason Bittel, Bats can sing—and this species might be crooning love songs, National Geographic, 15 February 2024 (subscription required); Robert Krulwich, Is That A Lark I Hear? A Nightingale? Surprise! It's A Bat, NPR, 1 October 2014.

Council Promotes Virtual Fences

Eurobodalla Council has passed a motion thanking WIRES and Coastwatchers for the successful trial of virtual fencing at Long Beach. It will promote it at the Australian Local Government Association’s National General Assembly.

Council’s General Manager said Council "should continue to champion this project, including consideration of a budget to enable a few kilometres per year of virtual fence to be installed on prioritised local roads.

"Council will also make representations to the Insurance Council of Australia to explain the success of the virtual fence, the subsequent reduction in insurance claims, and the potential for reduced premiums for councils where virtual fences are installed on local roads, and/or provision of funds for installation.”

The next Eurobodalla shire virtual fence will be installed along Dunns Creek Road between Mogo and Tomakin. Funding is from The Great Eastern Ranges and World Wide Fund for Nature Australia ($10,000) as well as Council ($10,000).

Ref: Eurobodalla to lead way with Virtual Fencing, Moruya Mail, 22 March 2024 (pdf).

Platypuses in Royal National Park

Platypuses have been discovered in the Royal National Park, Sydney, for the first time in 50 years. What is more there is evidence that they are breeding, as a 6 month old juvenile puggle has been found.

“Anecdotally, the nail in the coffin for the platypus population was a chemical tanker spill in the ’70s that apparently tipped over on the highway close by and all this gunk went into the [Hacking] river and the platypus was never seen again.”

Platypuses were released into the park a year ago after checks were made to ensure the river was clean with earthen banks for burrowing, and a good supply of food such as dragonfly larvae and yabbies.

The platypuses can now be found in the Hacking River and Kangaroo Creek (see map). Those wanting to see them can visit the picnic areas along the Hacking River, keeping to the tracks, around dawn or dusk and stay quiet.

Ref: Caitlin Fitzsimmons, ‘Words can’t describe’: Puggle magic in Royal National Park after 50 years, Sydney Morning Herald, 20 March 2024.

Premier Backs Return of Magpie

A Gold Coast couple adopted a magpie after it fell from its nest in 2020. The magpie made friends with their pet dog and videos of them playing and sleeping together went viral on Instagram.

However the authorities seized the magpie on 1 March as it is unlawful to keep a wild animal without a permit or licence in Queensland, as in NSW. The couple claims it had tried to work with the environment department to get the proper training and permit.

A petition, signed by nearly 10,000 people has called on the department to reunite Molly and Peggy. The Premier, Steven Miles, has urged the department to help reunite them by working with the couple to get the proper carer training.

Ref: Andrew Messenger, Molly the magpie: Queensland premier backs return of Instagram-hit bird to couple after being seized, The Guardian, 27 March 2024.

Clever Magpies Live in Big Groups

Newly published research has found that for Western Australian magpies, the larger the social group they live in, the better they are able to solve puzzles. Western Australian magpies, unlike the magpies in our area, live in large groups all year.

"We made wooden “puzzle boards” with holes covered by different-coloured lids. For each bird, we hid a tasty food reward under the lid of one particular colour. We also tested each bird alone, so it couldn’t copy the answer from its friends.

"Through trial and error, the magpies had to figure out which colour was associated with the food prize. We knew the birds had mastered the puzzle when they picked the rewarded colour in 10 out of 12 consecutive attempts.”

The researchers found that the more intelligent fledglings did not necessarily have more intelligent mothers, but came from larger social groups of 10 or more. The researchers believe this is because “a young magpie living in a group gets plenty of mental exercise recognising and remembering numerous individuals and relationships. Working to make sense of this stream of social information may boost their ability to learn and solve problems."

Ref: Elizabeth Speechley, The surprising key to magpie intelligence: it’s not genetic, The Conversation, 13 March 2024.

Flying-Fox Population Stable

The grey-headed flying-fox is listed as “vulnerable” to extinction but a CSIRO study has found that since 2012 their population in Australia have remained stable.

"While this study is good news for the species, we must not become complacent. Heatwaves are expected to become more frequent and intense as the climate changes.” And flying-foxes are particularly vulnerable to heatwaves.

The main flying-fox camp in the Eurobodalla is at the Batemans Bay Water Gardens, which has an estimated 2500 individuals. Other camps are at Moruya Riverside Park (550 individuals) and at Tuross (400 individuals).

Ref: Eric Vanderduys et. al., Grey-headed flying-fox population is stable – 10 years of monitoring reveals this threatened species is doing well, The Conversation, 22 March 2024.

Fire Ant Poison Killing Wildlife

Fipronil is a poison used to kill fire ants and varroa mite in Australia. It is available to the public at stores such as Bunnings. Yet it is banned in Europe because it is harmful to humans, poisons waterways and kills native fauna. It is banned in other countries for use on crops because it kills pollinators. Beekeepers in Australia are particularly concerned about its use.

"The insecticide was used in sugar baits across New South Wales in the now abandoned fight against the invasive varroa mite and has been injected into 35,539 fire ant nests in south-east Queensland and northern NSW since January 2023 as part of the national red imported fire ant eradication program.”

A recent senate inquiry has been told that fipronil is active in the environment for three years, can blow on the wind and move in water, and has the potential to kill bees, reptiles, birds and mammals.

The Australian Pesticides and Veterinary Medicines Authority (APVMA) began reviewing fipronil 22 years ago because of concerns about its impact but it has not completed the review.

"CSIRO data from 2017 showed fipronil from farm run-off was detected in Queensland’s Logan River at high enough levels to kill prawn populations. It is highly toxic to birds and there is a lack of data regarding its effects on amphibians, mammals, arthropods, reptiles – and humans.”

In fipronil's defence “a fire ant eradication spokesperson said the risk to the environment by using fipronil was far outweighed by the impact fire ants would have if not eradicated."

Ref: Daisy Dumas, ‘Wildly toxic’ poison used on fire ants is killing native Australian animals, experts warn Senate inquiry, The Guardian, 16 March 2024.

Antechinus Cannibals

It is well known that male antechinus die after frenzied mating during their breeding season (see newsletter June 2021). At this time "male and females mate promiscuously in frenzied bouts lasting as long as 14 hours”.

What is less well known is that when a male drops dead, other males and pregnant or lactating females eat the corpses for the energy they provide. This behaviour is rare among wild dasyurids (the family which includes antechinuses, quolls and Tasmanian devils).

Ref: Mini marsupial goes from mating fests to cannibal feasts, QUT News, 24 January 2024.

Why do Kangaroos Lick their Testicles?