Have you recently encountered an animal that you would rather avoid? As La Niña continues to give us rainy days, turkeys, bats and cockroaches come out of hiding.
We often think of them as pests, but these animals do their best to cope with heavy rains. They are also essential members of our urban ecosystems and help maintain environmental health.
Here’s what makes them so compelling and important to your neighborhood.
Bats: heavy rain hinders echolocation
Australia is home to several endangered species of fruit bats and microchiroptera, such as the grey-headed flying foxes, large curved-winged bats and spectacled flying foxes.
They are generally considered a nuisance for their noise, damage, and potential spread of disease. But bats are often overlooked for their ability to control insect pests, disperse seeds and pollinate plants.
Bats face serious threats in La Niña conditions. They can react to periods of heavy rain using a special physiological adaptation called torpor. In torpor, bats will sleep more and lower their body temperature so they can use less energy.
Image credit Dieter Hochuli
Microbats are abundant in Australian cities. They use echolocation to see, but heavy rain probably reduces this ability.
In 2019, Smithsonian researchers released recordings of downpours near bat roosts and found that bats were slow to emerge from their roosts. Delayed emergence can lead to disoriented bats with reduced ability to find food.
In Australia, rain may affect microbats more than fruit bats due to where they live. Many species of microchiroptera, such as the greater curved-winged bat, live in culverts and under bridges, where higher water levels can rush in during periods of heavy rain.
Fruit bats, such as flying foxes, do not use echolocation, but rain can wet their fur and lower their body temperature. They will therefore often remain on their perches to keep warm during heavy rains.
Read more: Fruit bats are the only bats that cannot (and never could) use echolocation. Now we’re closer to knowing why
It also costs a lot more energy for a bat to fly in the rain, making it harder to maintain a steady food supply. If there are consecutive rainy days, bats may fall from their homes due to starvation.
If you find a fallen bat, don’t touch it. Contact WIRES instead. Or wait to see if they leave once the rain clears.
Brush the turkeys: reshape their mounds
Bush turkeys are a type of ground-nesting bird found along the east coast of Australia from Cape York in Queensland to Wollongong in New South Wales. They are particularly vulnerable to the effects of heavy rains, which can damage or wash away their nests.
To incubate their eggs, brush turkeys build huge mounds of fallen leaves and mulch. These mounds can weigh several tons and measure up to 4 meters wide and up to 1 meter high. These mounds often cause consternation among avid gardeners and frustrated commuters.
But brush turkeys can be good for the environment. By scraping for food and building mounds, birds help break down fallen leaves and aerate the soil. This helps water and nutrients move through your soil, which ultimately helps your garden.
Image credit Matthew Hall
Winter rains are the trigger for males to start building their mounds, as the increased soil moisture provides the heat that incubates their eggs. However, research shows that males avoid building their nests during long periods of heavy rain.
Flood waters can wash away existing mounds, and after several weeks of rain, the mounds can become waterlogged. Flooding can drown eggs or reduce mound temperatures below levels needed for incubation, preventing chicks from developing properly.
Image credit John Martin
Brush turkeys are known to protect their mounds from heavy rain. Much anecdotal evidence suggests that brush turkeys can predict the weather in advance and reshape their mound accordingly.
During light rains, male brush turkeys open their mound, letting in much-needed moisture to speed the decomposition of leaf litter. But when heavy rains approach, they instead pile additional material on their mound, providing an extra layer of protection and creating a more conical shape so water can run off to the sides.
Next time, consider connecting to your local brush turkeys for weather forecasts. If you see them doing a little extra raking in your garden on gray, gloomy days, it could be a scramble to protect their nests from the oncoming heavy rains.
When you spot one, take the opportunity to snap a photo and upload it to the Big City Birds app. This app tracks where birds such as turkeys are and how they adapt to city life.
Read more: ‘Sad and distressing’: Massive number of bird deaths in Australia’s heatwaves reveal deep loss looms
Native cockroaches: evacuate to drier areas
As we settle into another wet spring, our homes become perfect breeding grounds for cockroaches. The humidity of a damp home combined with warmer weather allows cockroaches to grow faster and thrive.
Only a small handful of cockroach species will survive in an average home, and these are all introduced species. After the rain, it’s essential to make your home a little less welcoming to cockroaches. Reduce humidity by keeping the house well ventilated and be sure to remove all food scraps.
On the other hand, the waterlogged ground in your local green spaces is likely to be home to some of Australia’s 450 native cockroach species, so you might see some around your garden after a rain. Cockroaches play an important role in the ecosystem, breaking down nutrients in the soil.
image creditElise Oakman
Burrowing cockroaches can be spotted because they don’t have wings. Many of our other native cockroaches are evident due to their beautiful colors and patterns.
A stunning example is the Lord Howe Island wood-eating cockroach. Thought extinct for around 80 years because of rats, they were only recently rediscovered. This species is important because it recycles nutrients and serves as food for other animals.
Although native cockroaches may enter your home in an attempt to find warm, dry ground, they will not thrive indoors. If you find a native cockroach inside your home, instead of reaching for the insect repellent, it’s best to catch it and put it back outside.
Read more: A large cockroach thought extinct since the 1930s has just been rediscovered on a small island in Australia
So, in wet weather, take the time to remember that these animals are doing their best. All have amazing ways of adapting to heavy rain, and we should give them some slack – the environment, including our backyards, needs it.
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