Acoustic Sensory Ecology of Diving Alcid Seabirds and Potential Noise Impacts

Seabirds are important components of holarctic coastal ecosystems. As humans increasingly utilize these sensitive areas, deep-diving seabirds like alcids face a unique combination of pervasive anthropogenic sound exposure in terrestrial and marine environments. However, the acoustic sensory ecology of this threatened group is largely unknown, which complicates assessment of potential anthropogenic noise impacts. Here, aerial auditory sensitivities and nesting soundscapes are compared between three deep-diving alcids: the colonial-nesting common murre (Uria aalge) and Atlantic puffin (Fratercula arctica), and the solitary-nesting marbled murrelet (Brachyramphus marmoratus). Auditory evoked potentials (AEPs) were used to assess aerial hearing in temporarily sedated wild individuals placed inside a field-deployed anechoic chamber. For all species, AEPs were detected across a 0.5–6 kHz frequency range, similar to other birds with available data. Lowest mean auditory thresholds were between 16- and 35-dB SPL, while hearing was generally sensitive across a range extending from 1 to 3.5 kHz. Short-term soundscape dynamics of nesting habitats were also investigated via passive acoustic recordings which show that nesting acoustic environments can vary significantly among species. Overall, frequencies of sensitive hearing in each species overlap with many anthropogenic noise sources, indicating alcid susceptibility to disturbance from a range of noise types.