It is the end of the mango season and the fallen fruit is fermenting in the Kimberley sun, resulting in a boozy treat for the local wildlife.
In the past week, Broome Veterinary Hospital has treated a number of drunk red-winged parrots after they have consumed ethanol as a result of eating fallen fruit.
Broome veterinarian, Paul Murphy, said several lucky birds had been brought into the clinic.
“So far, we’ve seen about half a dozen in total, but there are a lot of them, unfortunately, that don’t make it to the clinic because they pass away before people find them,” he said.
“Usually, they’ve been suffering for a couple of days.
“That’s generally when people are able to pick them up and catch them. They’re quite lethargic and at various stages of malnutrition.”
The local veterinarian said it was not just alcohol that was killing the parrots, but their “drunken behaviour”’
“We’re hearing a few reports of flying into windows and sitting on the floor, not being able to fly and being vulnerable to cats and other predators,” he said.
It is unclear why red-winged parrots seem to be the only birds heavily affected by fermenting mangoes.
Some scholars suggest it could be because mangoes are the only wildly available fruit throughout the Kimberley that ferment potently.
Doctor Michael Considine, an Associate Professor in Plant Molecular Biology at the University of Western Australia, says it is all part of the ecological system.
“Once the fruit are ripe, the next phase will be fermentation where the sugars will take the pathway to become alcohol and that process makes the aroma compounds volatile which attract the birds and other animals,” he said.
“The ethanol is clearly serving some sort of ecological value for the tree.”
But not all tropical fruits can be as alcoholic as the humble orange fruit.
“Whereas a number of the other tropical fruits are not quite so dense and more watery.”
Mr Murphy warns the public not to assume a red-winged parrot is tame.
“Even if they let the person pick them up, generally it’s because they very unwell,” he said.
“Rather than taking it home and putting it in a cage, bring them to the vet so we can assess and see what it needs.”
Alcohol or illness?
In 2010, the ABC documented the same intoxication habits in lorikeets in Darwin.
But in 2016, Darwin-based vets found their lorikeets were dying due to illness, referred to as Drop Lorri Syndrome, rather than intoxication.
The Broome Veterinary Clinic is looking at whether or not ethanol poisoning, or something more sinister, is to blame for the birds’ deaths.
In the meantime, Professor Considine confirmed fermented mango is not harmful to humans because we are unlikely to eat a mango that has reached that point.
“It’s a unique smell,” he said.
“People would know if they were eating a mango that had gone so far as to have appreciable levels of alcohol.