idw – Informationsdienst Wissenschaft

Nachrichten, Termine, Experten

Grafik: idw-Logo
Grafik: idw-Logo

idw - Informationsdienst
Wissenschaft

Science Video Project
idw-Abo

idw-News App:

AppStore

Google Play Store



Instance:
Share on: 
12/22/2020 11:06

Global study on bird song frequency

Dr. Sabine Spehn Presse- und Öffentlichkeitsarbeit
Max-Planck-Institut für Ornithologie

    An analysis of the songs of most of the world’s passerine birds reveals that the frequency at which birds sing mostly depends on body size, but is also influenced by sexual selection. The new study from researchers of the Max Planck Institute for Ornithology and colleagues suggests that habitat characteristics do not affect song frequency, thereby refuting a long-standing theory.

    Many animals use acoustic signals for communication. These signals have evolved to maximize the effectiveness of the transmission and reception of the sounds, because this helps finding a mate or avoiding predation. One of the fundamental characteristics of acoustic signals is the frequency of the sound. In forested habitats, acoustic signals become attenuated because of sound absorption and scattering from foliage, which is particularly problematic for high-frequency sounds. Hence, a theory from the 1970s predicts that animals living in habitats with dense vegetation emit lower-frequency sounds compared to those living in open areas.

    A team of researchers led by Bart Kempenaers from the Max Planck Institute for Ornithology in Seewiesen and Tomáš Albrecht from the Charles University in Praha and the Czech Academy of Sciences analysed the variation in song frequency of more than 5.000 passerine bird species, encompassing 85% of all passerines and half of all avian taxa. PhD student Peter Mikula collected song recordings primarily from xeno-canto, a citizen science repository of bird vocalizations, and from the Macaulay Library of the Cornell Lab of Ornithology.

    Contrary to the theory, the study reveals that the peak frequency of passerine song does not depend on habitat type. If anything, the data suggest that species living in densely vegetated habitats sing at lower frequencies, which is the opposite of what was predicted.
    As expected from basic physical principles, the researchers found a strong relationship between song frequency and body size and an effect of shared ancestry. “Both limit the range of sound frequencies an animal can produce”, says first author Peter Mikula. Heavier species sing at lower frequencies simply due to the larger vibratory structures of the vocal apparatus.

    The study further reveals that species in which males are larger than females produce songs with lower frequencies than expected from their size. “This supports the hypothesis that the frequency of acoustic signals is affected by competition for access to mates”, says Bart Kempenaers. Song frequency may act as an indicator of an individual’s size and therefore of its dominance or fighting abilities. Thus, song frequency could influence reproductive success through competition with other males or even because it influences male attractiveness to females.

    “Our results suggest that the global variation in passerine song frequency is mostly driven by natural and sexual selection causing evolutionary shifts in body size rather than by habitat-related selection on sound propagation”, summarizes Tomáš Albrecht.


    Contact for scientific information:

    Prof. Dr. Bart Kempenaers
    Director
    Department of Behavioural Ecology and Evolutionary Genetics
    Max Planck Institute for Ornithology, Seewiesen
    Email: b.kempenaers@orn.mpg.de


    Original publication:

    Peter Mikula, Mihai Valcu, Henrik Brumm, Martin Bulla, Wolfgang Forstmeier, Tereza Petrusková, Bart Kempenaers & Tomáš Albrecht (2020). A global analysis of song frequency in passerines provides no support for the acoustic adaptation hypothesis but suggests a role for sexual selection. Ecology Letters
    https://doi.org/10.1111/ele.13662


    Images

    A global study of songbirds like this field warbler shows that song frequencies primarily depend on body size.
    A global study of songbirds like this field warbler shows that song frequencies primarily depend on ...

    Tomáš Albrecht


    Criteria of this press release:
    Journalists
    Biology
    transregional, national
    Research results
    English


     

    Help

    Search / advanced search of the idw archives
    Combination of search terms

    You can combine search terms with and, or and/or not, e.g. Philo not logy.

    Brackets

    You can use brackets to separate combinations from each other, e.g. (Philo not logy) or (Psycho and logy).

    Phrases

    Coherent groups of words will be located as complete phrases if you put them into quotation marks, e.g. “Federal Republic of Germany”.

    Selection criteria

    You can also use the advanced search without entering search terms. It will then follow the criteria you have selected (e.g. country or subject area).

    If you have not selected any criteria in a given category, the entire category will be searched (e.g. all subject areas or all countries).