Starlings treated with low doses of FENTANYL produce songs like ‘free-form jazz’

Birds given doses of the opioid-based fentanyl produce songs purely for pleasure that ‘sound like free-form jazz’ compared to birds not given the drug.

Researchers from the University of Wisconsin, Madison, found that when birds sing in flocks rather than for mating purposes it is ‘gregarious’ and gives them pleasure.

Birds don’t just sing to mark out territory or to find a mate, they also do it for pure enjoyment, the team said, adding it sounds like jazz when it is for pleasure.

The team believe that when birds sing it produces opioids in their brains and to prove their theory they gave starlings a doze of fentanyl then listened to their song.  

Biologist Lauren Riters and colleagues found that the song after the opioid drug was the same type of sound birds make when they get together in a flock. 

Previous studies into birdsong have focused on how it is produced and why it developed in the first place – this study looks at why they sing.

Researchers from the University of Wisconsin, Madison, found that when birds sing in flocks rather than for mating purposes it is ‘gregarious’ and gives them pleasure

There is a clear difference between songs sung with a purpose such as attracting a mate, and those sung purely for pleasure, according to Riters and colleagues.

‘When they’re practising, they try out different songs, they order and reorder and repeat song sequences, they add and drop notes,’ she said. 

‘It sounds a bit like free-form jazz and it is quite distinct from the structured songs that male songbirds produce when trying to attract mates. It is the free-form songs that are produced during practice that our studies show to be rewarding.’

To better understand this underlying pleasure birds get from ‘warbling’, Riters looked at the behaviour of a group of European starlings.

They decorated an area and put the birds inside after they had sung, then later gave them a choice of returning this area or an undecorated space.

The birds spent longer in the decorated area, suggesting they associated it with pleasure they gained from singing.

‘It’s evidence that a positive state is induced by the presence of flock-mates, which stimulates song, and that birds continue to produce gregarious song because it is rewarding,’ Riters said.

‘Although male songbirds are famous for singing when they are away from other birds, for example when they are defending territories and attempting to attract mates, many birds also sing at high rates in more social contexts. 

‘Our results suggest that birds sing because they feel good, and that singing helps them to maintain this positive state.’

Once they established the fact birds link singing to please, they wanted to find out exactly why – theorising it was due to the production of opioids in the bird brain. 

Opioid drugs like fentanyl, heroin and morphine are known for giving pleasure and reducing pain in animals – creatures also produce their own opioids. 

This production of the pleasure giving chemical plays a central role in rewarding positive behaviours including socialising, eating and mating.

Riters and her team gave the birds a low dose of fentanyl to induce artificial pleasure – designed to replicate levels expected when they sing for joy.

The team say this automatically triggered high rates of the type of warbling song seen when the birds are in the flock. 

When birds sing it produces opioids in their brains - to prove this the team, led by biologist Lauren Riters, gave starlings a doze of fentanyl then listened to their song.

When birds sing it produces opioids in their brains – to prove this the team, led by biologist Lauren Riters, gave starlings a doze of fentanyl then listened to their song.

‘Here we’ve shown that opioids cause singing behaviour,’ Riters said, adding that it also seemed to reduce stress-related behaviours in the birds.

They were also able to show the opposite – by using chemicals to switch off the opioid receptors in the brain they could reduce how much the birds sing.

The overall results suggest that the presence of flock mates may naturally lead to opioid release int he brain of birds and produce a positive, low-anxiety state.

They also found that singing in its own right can trigger this same response and the same findings in bird brains could apply to almost all animals.

‘If this is the case, it would mean that our studies on songbirds are revealing an ancient, evolutionarily conserved neural circuit that regulates intrinsically rewarded social behaviors across many animals,’ Riters told Psychology Today.

The discovery of an underlying link between socialisation and opioid release could help researchers develop treatments for people who are socially withdrawn. 

The findings have been published in the journal Scientific Reports. 

BIRDS USE SONG TO COMMUNICATE WITH OTHER BIRDS

Birds use their voices to communicate with other birds.

Sharp tunes are an efficient way to communicate over long distance, especially when you are small and live in dense habitats like rain forests.

Most bird species use specific calls to identify themselves and to communicate a nearby threat.

Birdsong is a specialised type of call used by many species to help them mate.

Almost exclusively a male activity, birdsong helps the singer to indicate he is fit, healthy and ready to breed.