The complex acoustic repertoire of a highly social species, the Noisy Miner,Manorina melanocephala

Abstract

Communication is an essential component of social interactions between individuals, particularly in larger group sizes. To gain further insight into the factors that underpin cooperative behaviour, herein we examine the acoustic repertoire of the Noisy Miner, Manorina melanocephala, a cooperative species that lives in large colonies. To determine the structure and composition of the Noisy Miner repertoire, we measured the call rates and major acoustic parameters of common vocalisations from colour-banded individuals located at two discrete colonies. A total of 13 different vocalisation types were identified, of which 3 are newly described, with an additional 10 vocalisations being quantified in a new social context. Importantly, we describe a call given only by females and document both sexes producing some calls that were previously thought to be sex-specific. The putative repertoire identified was supported by statistical assessments confirming differences in their spectral and temporal features. Vocalisations were given across a range of social contexts, including the mobbing of predators, aerial alarm vocalisations, apparent maintenance of group cohesion and advertisement of individual location and/or status. This study quantifies the rich vocal repertoire of this social species, and provides further implications for the link between cooperative breeding and large vocal repertoires.

Functionally referential alarm calls in noisy miners communicate about predator behaviour

“…Similarly, aerial alarms were given to gliding models or live, flying birds. These two call types are also consistent with previous spectrographic and quantitative descriptions of aerial and chur calls (Doohan, 2014;Holt, 2013;Jurisevic & Sanderson, 1994a, 1994bLowry et al, 2012;Magrath & Bennett, 2012;Wood, Sanderson, & Evans, 2000).…”

“…obs. ; Holt, 2013;Kennedy et al, 2009). In our sample of responses to raptor glider models, the mean aerial alarm call length was 1.7 s, with 1-2 calls being given over a period of 1-4 s. In response to taxidermic raptor models, chur calls were a mean length of 2.4 s, with calling lasting for between 6 s and 5 min (when the model was removed).…”

“…Noisy miners are aptly named, as they have a large repertoire of conspicuous vocalizations, including two alarm calls with a putatively distinct function (Holt, 2013). Chur alarm calls are given in the wild to potential predators that are on the ground, perched, or being harassed by miners (Higgins et al, 2001;Holt, 2013).…”

“…We studied noisy miners from April to September 2015 (primarily autumn and winter) in suburban parks and nature reserves in Canberra, Australia, where miners are common. Chur and aerial alarm calls are both common throughout the year, including autumn and winter (Doohan, 2014;Holt, 2013;personal observations).…”

“…Positive values meant that the fundamental was of higher amplitude than the mean of harmonics 2 and 3. We used this value because previous work on miners suggested that the fundamental is loudest in aerial alarms, but that harmonic 2 or 3 is loudest in chur calls (Holt, 2013;Jurisevic & Sanderson, 1994b;Kennedy et al, 2009;Magrath & Bennett, 2012). We did not measure amplitude (dB SPL) itself because we could not control for distance and bird orientation, and were interested specifically in the difference in structure between alarm-call types.…”