Source amplitude increases with body‐mass across avian genera

Amplitude, or intensity, of sound is a fundamental characteristic of acoustic communication, with relevance in many scientific fields. The amplitude of an animal's acoustic signal at its source (‘source amplitude’) may be particularly relevant in the field of acoustic allometry, where relationships between species' physical and acoustic features (e.g. dominant frequency) have been well‐established across taxa. However, despite their potential scientific value, records and studies of source amplitude remain remarkably scarce for avian species. Here we present novel estimates of source amplitude (range and median) for 17 species of Arctic‐breeding birds, derived from measurements made in Utqiaġvik, Alaska, during June 2024. We found a strong positive correlation between body‐mass and source amplitude in these data via Markov chain Monte Carlo multivariate generalized linear mixed models (MCMCglmms). This relationship was influenced by both phylogenetic and individual identity. In contrast, effects from environmental factors and measurement characteristics were minimal. Our work represents one of few studies that explicitly model an interspecific relationship between source amplitude and body mass across avian genera. We hope that this study will spur further investigations into avian source amplitude and its relationship to morphological and life‐history features for species in the Arctic and elsewhere.