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RESEARCH PRODUCT

A case of possible vocal convergence between frogs and a bird in Himalayan torrents

subject

description

Several species of frogs of the subgenusRana (Paa) and one species of bird of the genusPhylloscopus, which are calling in or near torrents in the Himalayas, show striking similarities in their vocal signals: 1) The calls are composed of short sequences of notes separated by periods of silence; 2) the notes are pure, short, and have a narrow frequency band; 3) within each sequence, the notes are rhythmically emitted. We suggest that these characteristics may be adaptive, the convergence being caused by the selective pressure of the acoustic constraints of the biotope.