A cost-effective Raspberry Pi-based operant playback setup to evaluate auditory preferences in songbirds

Preferences arise from the interplay of biological processes, past experiences, and environmental factors that shape decision-making and adaptive behaviour. Song preference is integral to cognitive processes and song learning in songbirds. Traditionally, measuring song preferences in the lab has required expensive commercial equipment, limiting accessibility and adaptability. The past decade, however, has seen an increase in the development and use of low-cost DIY equipment that can be used for research. Here, we built a cost-effective operant audio playback system using a Raspberry Pi Zero 2 W. We validated the operant audio playback system using a conspecific-heterospecific song preference task with black-capped chickadees (Poecilia atricapillus). Our system allows the birds to self-select acoustic stimuli through perch-hopping while automatically recording their behaviour. Birds chose between conspecific black-capped chickadee fee-bee songs vs heterospecific white-throated sparrow songs. We did not find evidence that birds prefer conspecific (predicted probability 44 %, with 90 % CI [22 %-72 %]) over heterospecific songs from our limited sample size. Several factors may have contributed to this outcome, including the testing of wild-caught birds in a laboratory environment, the novelty or acoustic similarity of the stimuli, and potential habituation over time. Preference dynamics also varied across individuals, possibly reflecting differences in age or prior experiences. Nevertheless, birds readily engaged with the operant preference testing system, validating the setup and paving the way for a wide range of future research questions. The operant preference setup is made with affordable parts and open-source software, offering similar features to commercial systems but at a lower cost.