Zoology - Theses
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ItemThe acoustic repertoire of the bell miner, Manorina melanophrys( 1989)Acoustic communication was studied in a population of the cooperatively-breeding Bell Miner, Manorina melanophrys (Family Meliphagidae), from March 1985 to May 1988 at Bundoora, Victoria. The study aimed to describe the acoustic repertoire of the Bell Miner and to investigate the function of vocalizations in the repertoire. An additional aim was to examine whether there were functional specializations of vocal signals associated with a cooperatively-breeding social organization. Eighteen adult calls and four juvenile calls were distinguished in the acoustic repertoire of the Bell Miner. Six adult calls were given only by females and one adult call was given only by males. For calls that were given by both sexes, there were no differences between males and females. Most calls that were analyzed showed difference s between individuals in some characteristics; however, only two calls showed strong evidence of individuality. The characteristic tink call appears to function as an interspecific territorial call, deterring other species of birds from entering the area occupied by a Bell Miner social unit. The tink call may also act as a contact call between birds. Female-specific calls are believed to function in courtship of males (assisting a female in obtaining a breeding position), in synchronizing reproduction between mates, in reinforcing the pair-bond between mates, in acoustic mate-guarding, and as contact calls during nesting (ensuring that the female’s mate and other birds in the social unit are aware of the female's activities). The individuality of the female-specific chuk-a-choo call may enable males to recognize their mates. The male-specific oar call is believed to function in establishing and reinforcing a pair bond. The mew call given by both sexes appears to function to elicit a begging response from young; to induce a bird to leave young when the caller is approaching; to signal to other birds that the caller is leaving the young; to encourage nestlings to fledge; and to lead fledglings away from danger. Observations also suggest that the mew call functions in advertising male helping behaviour. Recognition of males on the basis of this individually distinctive call may occur. Calls of the Bell Miner also function as alarm calls, mobbing calls (to confuse an intruder and to encourage it to move on, and to alert and attract other birds to a mobbing), distress calls (to attract birds to a caller held by a predator) and distraction calls (to attract an intruder's attention away from young). Juvenile calls are believed to function in soliciting food from adults, to signal a juvenile's location to adults and to attract adults. Other potential functions of calls are discussed. The specificity of vocal functions of the Bell Miner in the context of a cooperatively-breeding social organization was evaluated by comparisons with vocalizations reported in the literature for other species. Several vocal adaptations were identified that may be restricted to, or most prominent in, species with a cooperatively-breeding social organization: these include the possession of a general interspecific territorial call, acoustic courtship of males by females, and vocal advertising of helping behaviour. Vocal components of communal display behaviour of the Bell Miner may also have functions adapted to a cooperatively-breeding social organization.