If songbirds could compete in the reality TV competition “The Masked Singer” zebra finches will probably steal the show. That’s because according to new research from the University of California, Berkeley, they can memorize the signature sounds of at least 50 different members of their flock easily.
These boisterous, red-beaked songbirds, known as zebra finches, have been shown to select each other out of a crowd (or flock) based on the distinct song or contact call of a particular peer, in results recently published in the journal Science Advances.
Zebra finches have a near-human capacity for language mapping, much like people who can immediately tell which friend or relative is calling by the timbre of the voice of the person. In addition, for months and even longer, the results suggest, they will recall the distinctive vocalizations of each other.
Study lead author Frederic Theunissen, a UC Berkeley professor of psychology, integrative biology and neuroscience, said The amazing auditory memory of zebra finches shows that birds’ brains are highly adapted for sophisticated social communication,”
Theunissen and fellow scientists tried to calculate the extent and significance of the ability of zebra finches to classify their feathered peers based solely on their distinctive sounds. As a result, the birds that mate for life performed much better than expected, they found.
“For animals, the ability to recognize the source and meaning of a cohort member’s call requires complex mapping skills, and this is something zebra finches have clearly mastered,” said Theunissen.
A pioneer in the study of bird and human auditory communication for at least two decades, through his collaboration with UC Berkeley postdoctoral fellow Julie Elie, a neuroethologist who researched zebra finches in the forests of their native Australia, Theunissen acquired a fascination and appreciation for the communication skills of zebra finches. Their collaboration yielded innovative results on the communication abilities of zebra finches.
In colonies of 50 to 100 species, Zebra finches normally migrate around, flying apart and then falling back together. Usually, their songs are mating calls, while their distance or touch calls are used to decide where they are, or to find each other.
“They have what we call a ‘fusion fission’ society, where they split up and then come back together,” said Theunissen. “They don’t want to separate from the flock, and so, if one of them gets lost, they might call out ‘Hey, Ted, we’re right here.’ Or if one of them is sitting in a nest while the other is foraging, one might call out to ask if it’s safe to return to the nest.”
These days, in aviaries on and around campus, Theunissen holds a few dozen zebra finches, 20 of which were used in this latest experiment.
20 captive zebra finches were learned to differentiate between various birds and their vocalizations in a two-part experiment. Half of the birds were initially assessed for memorizing songs, while the other half were checked for distance or touch calls. They then shifted those duties.
Next as part of a reward scheme, the zebra finches were placed, one at a time, inside a chamber and listened to sounds. The objective was to train them to respond to specific zebra finches by hearing and memorizing many different renditions of the distinct vocalizations of those birds.
Bird subjects triggered an audio recording of a zebra finch vocalization by pecking a key within the chamber. They got birdseed if they waited until the six-second recording finished, and it was part of the reward category. They switched to the next recording when they pecked before the recording was over. They discovered, through many trials, which vocalizations will produce birdseed, and which ones to miss.
Next, more audio recordings of new zebra finches were added to the zebra finches, to teach them to discern which vocalizations belonged to which bird. Soon they learned to distinguish between 16 different zebra finches.
In fact, in the experiments, the zebra finches, both male and female, performed so well that the more difficult task of distinguishing between 56 different zebra finches was assigned to four of them. On average, they succeeded, based on their signature sounds, in identifying 42 different zebra finches. Plus a month later, they were still able to recognize the birds based on their distinctive calls.
Theunissen said I am really impressed by the spectacular memory abilities that zebra finches possess in order to interpret communication calls,” “Previous research shows that songbirds are capable of using simple syntax to generate complex meanings and that in many bird species, a song is learned by imitation. It is now clear that the songbird brain is wired for vocal communication.”
Kevin Yu and Willam Wood at UC Berkeley, in addition to Theunissen, are co-authors of the analysis.
- K. Yu, W. E. Wood, F. E. Theunissen. High-capacity auditory memory for vocal communication in a social songbird. Science Advances, 2020; 6 (46): eabe0440 DOI: 10.1126/sciadv.abe0440