Avoiding predation is key for surviving in the wild. Credit: Dr Niki Teunissen.
Original Published Date: 
Monday, July 26, 2021

Full article issued by Monash University.

An ARC-supported study led by Monash University researchers has revealed that purple-crowned fairy-wrens, when helping to defend family members against predators, are not as selfless as was previously thought.

'Such seemingly altruistic helping behaviour has puzzled biologists for a long time, because it does not make sense to risk your own life to help others without some offsetting benefits, but these have been hard to identify,' says lead researcher, Dr Niki Teunissen from the Monash University School of Biological Sciences.

Dr Teunissen studied purple-crowned fairy-wrens at Australian Wildlife Conservancy’s (AWC’s) Mornington Wildlife Sanctuary in the Kimberley, Western Australia. These birds form stable social groups consisting of a dominant breeding pair and up to nine subordinates, that can help raise young and defend against predators.

'Our new approach allowed us to work out what incentives drive anti-predator behaviours in social groups,' said Dr Teunissen. She presented different types of predators, that threatened adults or the young in the nest, and measured for each helper bird whether it defended against the two types of predator.

The researchers established that subordinate fairy-wrens defend the nest more often when they are more likely to inherit a breeding position in the group in the future. The researchers could calculate exactly how likely each bird is to inherit a breeding position in the group because they have studied this species for a long time and inheritance follows strict rules.

'Our findings show that subordinate helper fairy-wrens expecting to inherit the top spot in the group invest in saving the threatened young so that they have a larger group later on when they are a breeder themselves,' Dr Teunissen said. 'In other words, they are actually saving their own future helpers.'

The long-term study was supported by an ARC Future Fellowship to Professor Anne Peters and two Discovery Projects grants; DP150103595 and DP180100058.

Photo credit: 

Avoiding predation is key for surviving in the wild. Credit: Dr Niki Teunissen/Australian Wildlife Conservancy.