Field-based hearing measurements of two seabird species

Abstract

Hearing is a primary sensory modality for birds. For seabirds, auditory data is challenging to obtain and hearing data are limited. Here, we present methods to measure seabird hearing in the field, using two Alcid species: the common murre Uria aalge and the Atlantic puffin Fratercula arctica. Tests were conducted in a portable semi-anechoic crate using physiological auditory evoked potential (AEP) methods. The crate and AEP system were easily transportable to northern Iceland field sites, where wild birds were caught, sedated, studied and released. The resulting data demonstrate the feasibility of a field-based application of an established neurophysiology method, acquiring high quality avian hearing data in a relatively quiet setting. Similar field methods could be applied to other seabirds, and other bird species, resulting in reliable hearing data from a large number of individuals with a modest field effort. The results will provide insights into the sound sensitivity of species facing acoustic habitat degradation.

A field study of auditory sensitivity of the Atlantic puffin, Fratercula arctica

“…We measured the auditory sensitivity of nine wild Atlantic puffins [Fratercula arctica (Linnaeus 1758)] using AEP recording methods. The field-based AEP audiogram study was conducted in May 2018 and methods were nearly identical to a pilot study the prior year measuring the hearing of one Atlantic puffin and one common murre (Mooney et al, 2019b). The puffins were caught using a 10×1.5 m mesh net (10-cm diameter eye size) strung across multiple burrows at a rookery near Tjörnes, northern Iceland.…”

“…The auditory frequency range was then examined using tone bursts of the following frequencies: 0.125, 0.25, 0.5, 1, 1.5, 2, 2.5, 3, 4, 6 and 8 kHz (for further details on experimental birds, see Table S1). The tone presentation order was prioritized, starting with 2 kHz (a frequency generally heard well in birds and showing clear responses in the 2017 pilot tests; Maxwell et al, 2017;Mooney et al, 2019b). We collected what was expected to be a clear response and threshold at 2 kHz, then a general audiogram (i.e.…”

“…To determine AEP hearing thresholds, the CCF peak magnitudes were plotted as a function of stimulus SPL expressed in dB re. 20 µPa (further details shown in Mooney et al, 2019b). Intersection of the regression line with the zero-magnitude level was accepted as a threshold estimate (Nachtigall et al, 2007;Supin and Popov, 2007).…”

“…The AEP recording method has been used as a rapid, physiological technique to measure auditory sensitivity in many taxa including various bird species and groups such as owls, canaries, aquatic taxa and, as noted, cormorants (Beatini et al, 2018;Brittan-Powell et al, 2002Crowell et al, 2015;Henry and Lucas, 2010;Lohr et al, 2013;Maxwell et al, 2016). The method involves measuring the neurological responses from components of the auditory system, including the auditory nerve and brainstem nuclei, to controlled sounds (Burkhard et al, 2007;Mooney et al, 2019b). Additional physiological studies have measured cochlear action potentials (Chen et al, 1993;Gleich et al, 1995;Gummer et al, 1987;Köppl and Gleich, 2007;Patuzzi and Bull, 1991;Saunders et al, 1973;Sun et al, 2000).…”

The common murre (Uria aalge), an auk seabird, reacts to underwater sound

“…The importance of in-air acoustic cues for aquatic birds, with their often-boisterous calls, is well-documented (Aubin and Jouventin, 2002;Lengagne et al, 2004, Searby et al, 2004. Aerial hearing data have been obtained from several species of aquatic birds (Crowell et al, 2015;Crowell et al, 2016;Hansen et al, 2017;Maxwell et al, 2017;Mooney et al, 2019). Acoustic signals serve important purposes for individual and conspecific identification, as well as providing vital health information of chicks (Aubin and Jouventin, 2002;Searby et al, 2004;Lengagne et al, 2004).…”