title: In-air hearing of the great cormorant (Phalacrocorax carbo).
abstract: Many aquatic birds use sounds extensively for in-air communication. Regardless of this, we know very little about their hearing abilities. The in-air audiogram of a male adult great cormorant (Phalacrocorax carbo) was determined using psychophysical methods (method of constants). Hearing thresholds were derived using pure tones of five different frequencies. The lowest threshold was at 2 kHz: 18 dB re 20 µPa rms. Thresholds derived using signal detection theory were within 2 dB of the ones derived using classical psychophysics. The great cormorant is more sensitive to in-air sounds than previously believed and its hearing abilities are comparable to several other species of birds of similar size. This knowledge is important for our understanding of the hearing abilities of other species of sea birds. It can also be used to develop cormorant deterrent devices for fisheries, as well as to assess the impact of increasing in-air anthropogenic noise levels on cormorants and other aquatic birds.
authors.affiliation: Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark maxwell@biology.sdu.dk.
authors.forename: Alyssa
authors.identifier: http://orcid.org/0000-0002-0988-5437
authors.initials: A
authors.lastname: Maxwell
authors.affiliation: Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark.
authors.forename: Kirstin Anderson
authors.initials: KA
authors.lastname: Hansen
authors.affiliation: Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark.
authors.forename: Sara Torres
authors.initials: ST
authors.lastname: Ortiz
authors.affiliation: Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark.
authors.forename: Ole Næsbye
authors.initials: ON
authors.lastname: Larsen
authors.affiliation: Institute for Terrestrial and Aquatic Wildlife Research (ITAW), University of Veterinary Medicine Hannover, Foundation, Werftstrasse 6, Büsum D-25761, Germany.
authors.forename: Ursula
authors.initials: U
authors.lastname: Siebert
authors.affiliation: Marine Biological Research Centre, Department of Biology, University of Southern Denmark, Hindsholmvej 11, Kerteminde DK-5300, Denmark.
authors.forename: Magnus
authors.initials: M
authors.lastname: Wahlberg
keywords: Aquatic birds; Hearing; Psychophysics; Signal detection theory; Unbiased hearing sensitivity