Acoustic communication in the Red-vented Bulbul Pycnonotus cafer

Abstract

This paper deals with acoustic communication in the Red-vented Bulbul Pycnonotus cafer. This species emits a high variety of vocal signals that can be classified on the basis of their acoustical features and context of production. Individuals sang throughout the year and most songs were discrete and stereotyped. The songs were composed of strophes (phrases) with minor structural variations of elements that were preceded and followed by a temporal gap (3 to 12s). Most strophes were composed of 2 to 6 elements that were often dissimilar in structure and ranging from 0.98 to 4.5 kHz. The biological function of the song appeared to be to maintain pair bonds and to synchronize breeding activities. Different types of context-specific calls were identified. Individuals produced Type-I alarm calls (fast and wide-band, 1.03 to 6.36 kHz) under low predation pressure and Type-II calls (narrow frequency range, 1.37 to 3.39 kHz) under high predation pressure. Roosting calls were fast and wide-band signals phonetically similar to Type-I alarm calls. Three types of begging/contact calls were recorded in nestlings/fledglings. Greeting calls and flight calls were composed of complex phrases, like song, but were short and used for proximate functions.

Species-distinctiveness in the vocal behaviour of six sympatric bulbuls (genusPycnonotus) in South-East Asia

“…The remaining two species can be distinguished on the basis of their frequency range (Stripe-throated Bulbuls have the lowestpitched frequency-modulated songs in the group) and the organisation of elements (Black-crested Bulbul songs tend to rise in pitch much more noticeably than the other species). These four species are most similar to published descriptions of the songs of Red-vented Bulbul (songs of 2-6 elements, frequency range of 0.9-4.5 kHz; Kumar 2004) and the Common Bulbul (P. barbatus) (songs of 4-7 elements, frequency range of 1.2-3.5 kHz; Lloyd et al 1999). Our acoustic descriptions can assist ornithologists, ecologists and conservation biologists in their future research endeavours.…”

Acoustic location of conspecifics in a nocturnal bird: the corncrake Crex crex

“…At the other extreme, there are alarm calls with acoustic structures making them hard to locate (Klump et al 1986; McGregor and Dabelsteen 1996). Such vocalisations, as might be predicted, have narrow frequency spectra and lack modulation (Kumar 2004; Marler 2004). Territorial call of the corncrake looks like a textbook example of the sound from the first group: it has wide-frequency spectrum and pulsating amplitude-modulated structure (Ręk and Osiejuk 2011).…”

Call Types of the Oriental Magpie Robin (Copsychus saularis) in Suburban Areas in Kota Samarahan, Sarawak

“…In many species, threat calls are responsible in deterring intruders or any potential disturbances that exist within their breeding territory (Kumar & Bhatt, 2001;Kumar, 2004;Sethi et al, 2012). Results have defined threat calls as a narrow range of frequency while having an abrupt onset and termination, and these characteristics resemble mobbing calls in many species (Johnson et al, 2003).…”

“…Distress calls in the Magpie robins can be described as loud, harsh, having an abrupt onset and termination and possesses slightly wider and higher range of frequency in comparison to threat call. Having similar characteristics just like threat calls is probably to enhance and pronounce their conspicuousness in order to get help by conspecifics during stress situation (Kumar & Bhatt, 2001;Kumar, 2004;Marler & Slabbekoorn, 2004;Sethi et al, 2012). The responses of birds upon stress situation varied across species.…”