When it comes to affairs of the heart, there are a variety of factors at play: mutual attraction, shared interests, an intangible spark that eventually leads to love. But in Darwinian terms, the recipe for reproduction is far more clinical, with animals seeking mates based on the potential evolutionary advantage—often superior cognition skills—offered by a match.
Now, a new study published in the journal Science suggests that female budgerigars, a species of small Australian parrots better known as budgies, employ this selective brand of logic when playing the mating game. As Nick Carne writes for Cosmos, a team of Chinese and Dutch researchers found that female budgies preferred brains over beauty and brawn. The birds would even change their selection if the previously overlooked mate learned a new trick.
To test budgies’ mating preferences, a team of researchers led by Jiani Chen of the Chinese Academy of Sciences’ Institute of Zoology, put 34 male and 17 female birds to the test. According to Forbes, the animals were split into a problem-solving group of 18 males and 9 females and a control group of 16 males and 8 females.
In order to watch interactions unfold, the scientists placed three birds into a divided enclosure in which the female could only engage with one male at a time, reports Agence France-Presse. Females in both groups were observed choosing between two similar-looking males, as determined by which male the female bird opted to spent more time with. Past studies structured this way have shown that females will gravitate toward males with beautiful feathers or skilled singing, as two behavioral experts not involved in the study, Georg Striedter and Nancy Burley—both from the University of California, Irvine—explain in an editorial analyzing the new study that was also published in Science.
In trials, the team used food to sweeten the pot. At first, the birds were allowed to chow down freely until the female bird appeared to show a preference for one beau over the other. But once it was clear which male bird had won the female budgie’s attention, the team introduced a game-changing new element to the experimental group, upending seemingly stable pairings in favor of more complex love triangles.
While the new couple continued courting, the researchers trained the rejected budgie to open two puzzle toys—a petri dish and a three-step box—filled with food.
Next, Carne reports for Cosmos, the scientists brought the newly-skilled budgie back out to the mating arena. As the female bird looked on, the once-lovelorn male successfully demonstrated his new puzzle-solving abilities, while the hapless untrained male tried and failed to keep his paramour’s attention.
Following this observational period, the female budgies again chose between the two potential mates. This time, the lady birds overwhelmingly opted for the previously spurned male, leading the team to conclude, that “female budgerigars modified their mate preference in favor of trained males after observing them perform complex foraging tasks.”
Still, the study has its faults: As Striedter and Burley note, the female budgies didn’t have the opportunity to perform the foraging puzzle themselves, indicating they may not have fully understood its merits as “a problem in need of a clever solution.” Instead, it’s possible the birds saw the trained males’ food-securing abilities as a display of physical strength, or perhaps a more impressive show of foraging effort.
Alex Kacelnik, a behavioral ecologist at the University of Oxford who was not involved with the study, tells Forbes that the team’s findings speak to two distinct explanations: “The females may prefer competent males because they will provide direct benefits (i.e., better males increase the female’s access to food) or because they have heritable traits that are passed to the offspring.”
Overall, Kacelnik says, “The theoretical implications of this study are rich, and worth tackling in depth.”