Interviewer experience, vocal skills and the recruitment of telephone survey respondents

Although telephone interviewing is the main market research method used in Australia, response rates are often low and possibly declining overall. Interviewers are the means by which respondents are recruited and it was hypothesised that their verbal skills and experience would affect response rates. Using data from four market research companies, interviewer experience was shown to be positively related to strike rate (interviews per hour). Apart from having a discernible accent which dampened strike rates and increased refusals, other verbal characteristics had only a weak effect on response rates.

Acoustic features involved in the neighbour-stranger vocal recognition process in male Australian fur seals

Many territorial species have the ability to recognise neighbours from stranger individuals. If the neighbouring individual is assumed to pose less of a threat, the territorial individual responds less and avoids unnecessary confrontations with familiar individuals at established boundaries, thus avoiding the costly energy expenditure associated with fighting. Territorial male Australian fur seals respond more to strangers than to neighbouring males. The present study evaluated which acoustic features were important in the neighbour–stranger recognition process in male Australian fur seals. The results reveal that there was an increase in response strength or intensity from males when they heard more bark units, indicating the importance of repetition to detect a caller. However, lengthening and shortening the inter-unit spaces, (i.e. changing the rhythm of the call) did not appear to significantly affect an animal's response. In addition, the whole frequency spectrum was considered important to recognition with results suggesting that they may vary in their importance. A call containing the dominant and surrounding harmonics was considered important to a male's ability to recognise its neighbour. Furthermore, recognition occurs even with a partial bark, but males need to hear between 25 and 75% of each bark unit from neighbouring seals. Our study highlights which acoustic features induce stronger or weaker responses from territorial males, decoding the important features in neighbour–stranger recognition.

Does the ring species concept predict vocal variation in the crimson rosella, Platycercus elegans, complex?

Vocal variation may be important in population divergence. We studied geographical variation in contact calls of parrots of the crimson rosella, Platycercus elegans, complex, which is characterized by striking geographical plumage coloration variation. This complex has long been considered a rare example of a ring species (where two divergent forms coexist in sympatry but are connected by a chain of intermediate populations forming a geographical ring). We tested whether contact call variation is consistent with the ring species hypothesis. We recorded calls throughout the ring, including several sites from the three main population groups forming the ring and interfaces between them. We analysed duration, peak frequency, fundamental frequency and frequency modulation. We found significant differences, particularly in fundamental frequency and frequency modulation, at multiple biogeographical scales ranging from local populations to subspecies level. Discriminant function analyses showed some populations could be reliably discriminated from call structure. However, our results provided little support for three key predictions of the ring species hypothesis: (1) calls of the terminal, most divergent forms were not significantly different in three of the four acoustic variables, and differences did not appear to be maintained in sympatry, (2) phenotypically/geographically intermediate populations were not characterized by intermediate calls, and (3) call variation was not concordant with geographical sequence around the ring from one terminal form to the other. Our results underscore the emerging view that the evolutionary histories and phenotypic variability of many long-held ring species may be inadequately described by the ring species hypothesis and require alternative explanations. (C) 2008 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.

Vocal mimicry in songbirds

Baylis (1982, Acoustic Communication in Birds, Academic Press) decried the serious lack of experimental verification for the various hypotheses proposed to explain vocal mimicry in songbirds. With few exceptions, our understanding of the function and acquisition of this fascinating behaviour seems to have scarcely progressed. We examine the proposed functional explanations and supporting evidence, and summarize advances made since Baylis's (1982) review. We conclude that there is no compelling evidence to support any of the functional hypotheses but, rather, that almost all of the data concerning song mimicry are consistent with the learning mistakes hypothesis, whereby birds learn simple and common sounds, frequently using them in inappropriate contexts. Additionally, many apparently mimicked sounds are calls, not songs, which themselves may not be learned by the models. It is plausible that many examples of call mimicry are, in fact, due to evolutionary convergence.

Vocal mimicry in male bowerbirds : who learns from whom?

Vocal mimicry is one of the more striking aspects of avian vocalization and is widespread across songbirds. However, little is known about how mimics acquire heterospecific and environmental sounds. We investigated geographical and individual variation in the mimetic repertoires of males of a proficient mimic, the spotted bowerbird Ptilonorhynchus maculatus. Male bower owners shared more of their mimetic repertoires with neighbouring bower owners than with more distant males. However, interbower distance did not explain variation in the highly repeatable renditions given by bower owners of two commonly mimicked species. From the similarity between model and mimic vocalizations and the patterns of repertoire sharing among males, we suggest that the bowerbirds are learning their mimetic repertoire from heterospecifics and not from each other.

Vocal individuality of in-air Weddell seal (Leptonychotes weddellii) pup "primary" calls

As a result of selective pressures faced during lactation, vocal recognition may play a crucial role in maintaining the phocid mother–pup bond during the period of dependence. To investigate this possibility, we examined whether Weddell seal (Leptonychotes weddellii) pups produce individually distinctive “primary” calls. One temporal, nine fundamental frequency features, and two spectral characteristics were measured. A discriminant function analysis (DFA) of 15 Vestfold Hills pups correctly classified 52% of calls, while the cross-validation procedure classified 29% of calls to the correct pup. A second DFA of 10 known-age McMurdo Sound pups correctly classified 44% of “test” calls. For novel calls, the probabilities of attaining such classification rates by chance are low. The relationship between age and call stereotypy indicated that pups 2 wk and older may be more vocally distinctive. Overall, findings suggest that Weddell seal pup “primary” calls are moderately distinctive and only exhibit sufficient stereotypy to aid maternal recognition by approximately two weeks of age.

Vocal mimicry

What is vocal mimicry? Vocal mimicry occurs when an individual learns a sound from another species or the environment. It differs from other animal vocalisations such as bird song or human speech, as these are learned from members of the same species (conspecifics). Parrots are the most renowned mimics, with reports of their talents dating back at least to the early 1500s with Henry VIII of England's pet African grey parrot, Psittacus erithacus, which mimicked his servants' voices.

Deeper than the forest AMBIENT with VOCAL

A short instrumental featuring ethereal female vocals, percussion, bells, synths, mandolin, and sound design.

Allelujah (female vocal led dreamy)

Allelujah is a cinematic and New Age piece that also fits well with projects of a religious or spiritual theme; Christmas and Easter included. It centers on a female vocal singing Alleluia, with violin, cello, piano, harp and 2 synths and bells at the very end.

Allelujah vocal 01

Allelujah Vocal 01 is a short vocal piece featuring a female voice singing Allelujah.

Allelujah vocal 03

Allelujah Vocal 03 is a short vocal piece featuring a synthesized female voice singing Allelujah.

Ave (piano and vocal) DREAMY

This audio features vocals, piano, strings, synth and bells a curious and unique piece with a light feel.