title: Why longer song elements are easier to detect: threshold level-duration functions in the Great Tit and comparison with human data.
abstract: Our study estimates detection thresholds for tones of different durations and frequencies in Great Tits (Parus major) with operant procedures. We employ signals covering the duration and frequency range of communication signals of this species (40-1,010 ms; 2, 4, 6.3 kHz), and we measure threshold level-duration (TLD) function (relating threshold level to signal duration) in silence as well as under behaviorally relevant environmental noise conditions (urban noise, woodland noise). Detection thresholds decreased with increasing signal duration. Thresholds at any given duration were a function of signal frequency and were elevated in background noise, but the shape of Great Tit TLD functions was independent of signal frequency and background condition. To enable comparisons of our Great Tit data to those from other species, TLD functions were first fitted with a traditional leaky-integrator model. We then applied a probabilistic model to interpret the trade-off between signal amplitude and duration at threshold. Great Tit TLD functions exhibit features that are similar across species. The current results, however, cannot explain why Great Tits in noisy urban environments produce shorter song elements or faster songs than those in quieter woodland environments, as detection thresholds are lower for longer elements also under noisy conditions.
authors: Animal Physiology and Behaviour Group, Fakultät V, IBU, and Research Center Neurosensory Science, Carl von Ossietzky University Oldenburg, Carl-von-Ossietzky Str. 9-11, 26129, Oldenburg, Germany.
authors: Nina U
authors: NU
authors: Pohl
authors: Hans
authors: H
authors: Slabbekoorn
authors: Heinrich
authors: H
authors: Neubauer
authors: Peter
authors: P
authors: Heil
authors: Georg M
authors: GM
authors: Klump
authors: Ulrike
authors: U
authors: Langemann
mesh_terms: D000161:Acoustic Stimulation; D000819:Animal Communication; D000818:Animals; D001309:Auditory Threshold / Q000502:physiology*; D003216:Conditioning, Operant / Q000502:physiology*; D005364:Field Dependence-Independence; D006801:Humans; D008297:Male; D046109:Passeriformes / Q000502:physiology*; D010470:Perceptual Masking / Q000502:physiology*; D017603:Signal Detection, Psychological / Q000502:physiology*; D013018:Sound Spectrography; D013045:Species Specificity; D013997:Time Factors