The University of Auckland conducted research on New Zealand’s smallest bird, the rifleman or titipounamu, to determine if they have the ability to learn and produce new sounds. This study is part of a larger rethinking of how and when vocal learning evolved in birds. Traditionally, scientists believed that birds could be split into two groups, those that could learn sounds (parrots, songbirds, and hummingbirds) and those that could not. However, this study challenges that assumption by suggesting that titipounamu may have a rudimentary form of vocal learning based on their vocal signatures. The research showed that closely related birds living near each other had strong similarities in their sounds, while close relatives living far apart did not sound similar.
Titipounamu weigh the same as five or six paper clips and live in high-altitude mature native forests. They feed on insects and produce high-pitched sounds that are inaudible to some people. This bird is one of New Zealand’s two surviving native wren species and is considered an evolutionary missing link between songbirds and parrots. The wrens likely existed in Aotearoa before the islands broke away from the supercontinent of Gondwana around 80 million years ago. The researchers involved in the study believe that if New Zealand wrens are vocal learners, then the common ancestor of parrots and songbirds must have also been capable of rudimentary learning, suggesting that the ability in birds could have evolved earlier than previously thought.
The study conducted by the University of Auckland researchers gathered evidence of vocal copying in titipounamu, such as vocal convergence, where animals’ calls become acoustically similar. This was done by monitoring nests, identifying and banding individuals, recording calls made by adult birds bringing food to nestlings, and conducting detailed analysis of spectrograms to reveal unique vocal signatures. Genetic information on the population was also acquired, and advanced genetic methods were used to estimate how much of the vocal signature came from genetics versus the social environment. The study’s findings are strongly suggestive of rudimentary vocal learning abilities in the titipounamu, challenging the classification of birds as either vocal learners or non-learners.
Vocal learning in birds such as songbirds and parrots is believed to have evolved millions of years ago, but the research on titipounamu suggests that the ability may be much more widespread among birds than previously thought. The researchers found similarities between the titipounamu and a known vocal learner, the zebra finch, indicating that the ability to learn new sounds may exist along a spectrum in birds. The study combined various scientific disciplines, including bioacoustics, genetics, behavioural ecology, and field biology, and utilized advanced technology such as artificial intelligence and custom analysis tools. The researchers acknowledged the support of various organizations and individuals involved in the study, including the Maungaharuru region mana whenua, the University’s engineering team, the Department of Conservation, AgResearch, and the Centre for eResearch.
Overall, the research on the titipounamu suggests that the ability to learn and produce new sounds may be more common among birds than previously believed. By studying the vocal signatures of these birds and analyzing genetic information, researchers were able to provide evidence supporting the existence of rudimentary vocal learning abilities in the titipounamu. This finding challenges the traditional classification of birds as either vocal learners or non-learners and highlights the need to consider the possibility of a spectrum of vocal learning abilities in birds. The study showcases the interdisciplinary nature of scientific research and the importance of technological advancements in unraveling complex behaviors in animals.