Pulling Swifties: How Parrot Polyamory Is Further Threatening The Species
Sugar gliders target nesting females
What you need to know
- The swift parrot is critically endangered
- Males outnumber females 3-to-1 due to sugar glider attacks on nests
- Now females are breeding with multiple males - and it's leading to lower rates of survival for hatchlings
Tasmania’s swift parrot is critically endangered, and there’s a new threat to the survival of the species: extra-marital affairs.
While the colourful bird is traditionally monogamous, a study by the Australian National University has found that males now outnumber females by three-to-one. And the battle over the affections of the female parrots has put young hatchlings at risk.
"The females are breeding with more than one male and there is a real cost to the population," the study's lead author Professor Rob Heinsohn told the ABC.
The population is down to an estimated 1,000 breeding pairs. And the numbers are plummeting due to vicious sugar glider attacks.
Sugar gliders have disproportionately attacked female swift parrots while they are incubating eggs in tree-hollow nests, leading to the large gender imbalance.
The female swift usually settles down with a single partner, and will call out a distinctive song for her partner to bring her food – and in exchange, to get a bit of parrot action.
However, the leftover single males aren’t willing to just shake off their jealousy. Increasing numbers of horny blokes are rocking up to the nests to feed – and harass - the females for sex.
According to The Guardian, Professor Heinsohn said the females usually gave in, “but they do it sneakily behind the resident male’s back”.
DNA tests from the researchers revealed hatchlings from multiple fathers in more than half the nests.
The problem is that the breeding pair is spending less time than usual looking after their brood.
“They are spending so much of their time, the male in defending the female and the female avoiding being harassed, that it’s affecting their ability to get food,” Professor Heinsohn said.
The resulting lower survival rates for hatchlings could reduce the parrot’s population by a further 5 per cent, on top of the 50 per cent reduction in the female population observed due to the sugar gliders, which were introduced from the mainland in the 19th century.
"They don't have any defences against this predator because they didn't evolve with them," Professor Heinsohn said.
The government is moving to cull sugar gliders, but the researchers are looking at other means of protecting the parrots, including the use of special nest boxes with a solar-powered door which shuts at night to keep the birds safe.
But even if the parrots are protected from the gliders, the skewing of the sex ratio might continue to drive populations down.
And that’s not to mention the effect of logging on their breeding habitat.
“I am not confident at all [that the species will survive],” researcher Dr Dejan Stojanovic said. “We have been working on swift parrots for the last decade, we know so much about them, even to the point that we know about their sex lives now … but even though we know so much, we are actively logging their habitat.
“We are wilfully pushing the things that are going to lead to their extinction.”
Featured Image: AAP Image/ANU