Australasian Science: Australia's authority on science since 1938

Birds of a Smelly Feather Lay Together

Crimson rosellas rely not just on sight but also their sense of smell to sniff out the lingering odour of their own species’ smelly feathers, according to Deakin University research into the olfactory senses of the beautiful Australian birds.

PhD student Milla Mihailova, who led the project, said the findings indicate that birds’ olfactory senses may play a larger role in ecology and evolution than previously thought. “It has always been said that birds had no sense of smell, but these findings indicate that they rely on their olfactory senses to communicate with one another and possibly even choose mates,” she said. “Unlike other animals, including dogs and cats, we don’t see birds actually sniffing things.”

Mihailova found that female crimson rosellas preferred to sit on their eggs in nest boxes that had the odour of another rosella, and they also favoured boxes that smelt like a male rosella. She said this could help explain why rosellas smell so strongly.

“When we work with them, we have to spend a lot of time washing the smell of them off our hands because the rosellas have a very robust odour,” she said. “Even birds that have been dead for more than 30 years but are kept as curios in museums retain their very strong scent.”

Mihailova and co-workers set out specifically to test if female crimson rosellas could discern the distinctive odour of their own subspecies and whether they could also spot a difference between the sexes. After more than 2 years they found that the females preferred going to nest boxes that carried the waft of a male over the smell of another female.

“I think the fact that a bird can sniff out its own subspecies, species and the sexes is amazing,” she said. “The preference of female crimson rosellas to spend more time in and on a nesting box that smells more of a male suggests it may play a role in sexual selection for this species.

“Also, we found that birds could discriminate subspecies based on their odour alone, so subspecies divergence and maintenance may be explained by smell.”

The research was published in Animal Behaviour.