The bird that weighs the same as a teaspoon of sugar
Becky Crew is a Sydney-based science communicator with a love for weird and wonderful animals. From strange behaviours and special adaptations to newly discovered species and the researchers who find them, her topics celebrate how alien yet relatable so many of the creatures that live amongst us can be.
IT’S ALMOST IMPOSSIBLE to imagine, but the mallee emu-wren (Stipiturus mallee) – a sweet little songbird that’s found in a tiny pocket of land in Victoria – weighs just 4 grams.
That’s less than a sheet of paper, a pen, or a human eye.
It’s so small, its eggs are the size of a pea, and as a fully grown adult, it can pass through the standard aviary mesh that scientists use to catch birds in the wild for tagging and surveying.
It’s a neat little trick, but doesn’t exactly help the mallee emu-wren’s cause – these tiny birds are down to their last 15,000 individuals, and they’re trying to survive in fragmented populations spread across the Murray-Sunset region of north-western Victoria.
They’re so rare these days, bird enthusiasts consider them the ‘Holy Grail’.
Mini emu birds
There are three species of emu-wrens, and they’re all endemic to Australia.
There’s the mallee emu-wren, which stretches 16.5 centimetres from head to the tip of its remarkable tail, which comprises two-thirds of its total length.
There’s the southern emu-wren (pictured above), which grows up to 19 cm long and about 7 grams, and found all along the east coast of Australia, from south-eastern Queensland through to Tasmania, and west to south-eastern South Australia. It’s also found in the south-western corner of Western Australia.
And finally, there’s the rufous-crowned emu-wren, which is considered the most brightly coloured of the emu-wrens, and stretching just 15 cm long, is the smallest and shortest of the three species. But weighing in at 6 grams, it’s considerably heftier than the mallee emu-wren.
The rufous-crowned emu-wren is found in the spinifex grasslands of central Australia, and in a number of sites around Alice Springs.
The emu-wrens got their name from their wonderful tail, which is made up of six filamentous feathers that look exactly like emu feathers, especially when they’re held up like this:
Southern emu-wren.(Image Credit: Chris Chafer/Flickr)
It’s a pretty cool thing when you can find such a distinctive link between one of Australia’s tiniest birds, and one of its largest.
World-first rescue plan
While the southern emu-wren and the rufous-crowned emu-wren are fairly secure in their coastal and inland populations, the mallee emu-wren is having a particularly bad time of it.
Until recently, it was found only in a couple of small areas in north-western Victoria and south-eastern South Australia, but then the wildfires of January 2014 all but wiped out the South Australian population.
Now we’re only left with the Victorian population, and since the birds don’t like to stray more than 5 km from their territory, they’re going to have a tough time redistributing themselves.
The good news is that Monarto Zoo in South Australia, one of the largest open-area zoos in the world, has been building a specialised emu-wren enclosure, where it’s hoping to raise an “insurance population” of the mallee emu-wren, in case bush-fires threaten to wipe out the Victorian population too.
The plan is to trial the enclosure using rufous-crowned emu-wrens before attempting to breed mallee emu-wrens inside.
And of course, they still have to catch some of these birds first, and without the help of an aviary net, this project is going to be a challenge from the very beginning.
To give you an idea of how tricky these things are to spot, here’s some footage of mallee emu-wren (and weebill and splendid fairy wren!) territory: