NEW DELHI: Scientists have discerned a strong correlation between vocal learning and problem-solving in songbird species.
Some species of songbirds, with versatile abilities in whistling, calling, and singing developed all through their lives, rank among the most advanced avian vocal learners.
According to a long-standing hypothesis, only the most intelligent animals are capable of complex vocal learning, said Jean-Nicolas Audet, a research associate in the laboratory of Erich Jarvis at The Rockefeller University, US.
"If that is true, then complex vocal learners should also be better at cognitive tasks, but no one had ever demonstrated that before," said Audet.
Audet and colleagues spent three years catching hundreds of wild birds from 21 songbird species in mist nets at The Rockefeller University Field Research Center.
Upon ranking the vocal learning capabilities of their subjects, three frontrunners emerged: starlings, blue jays, and gray catbirds (relatives of mockingbirds).
These were also the only three capable of mimicking other species, which Audet calls the "the epitome of vocal learning".
The team then ran a battery of cognitive tests on 214 birds from 23 species, including two lab-raised bird species, tests that measured their problem-solving abilities, self-control and making associations and connections.
Starlings, bluejays, and catbirds were not only the most advanced vocal learners, but also the most adept at solving puzzles, and vice-versa - the better a bird was at working its way around obstacles to nab a treat, the more complex its vocal learning ability, the researchers found using statistical analyses.
This suggested a strong correlation between vocal training and problem solving, they said in their study published in the journal Science.
There was no association between the other cognitive tests and vocal learning complexity.
Advanced vocal learners and problem solvers were also found to have brains larger than their body sizes.
Overall, the findings suggest that vocal learning, problem solving, and brain size may have evolved in tandem, perhaps as a way of increasing biological fitness, the researchers said.
"Our findings help support a previously unproven notion: that the evolution of a complex behaviour like spoken language, which depends on vocal learning, is associated with co-evolution of other complex behaviours," said Jarvis, co-corresponding author on the study.