Eric Vallet

Female canaries are sexually responsive to special song phrases

The sexual responsiveness of female canaries, Serinus canaria, to six different types of male song phrases extracted from natural song was tested. Copulation solicitation displays were used as an index of female sexual response. Playbacks were performed several days before and during egg laying (a period of natural sexual responsiveness of the females to song). Female canaries were especially responsive to particular short phrases whose essential features were abrupt frequency fall and short silences. This differential responsiveness occurred whatever the serial position (beginning, middle or end) of the phrase in the song and its serial relationship to other different conspecific phrases as well as the general song context (conspecific or heterospecific phrases). Influences such as early experience or ‘sensory bias’ that may lead to a particular sexual sensitivity of female canaries to these types of song phrases are discussed.

Obtaining copulation solicitation displays in female canaries without estradiol implants

Female domesticated canaries (Serinus canaria) respond to conspecific song with copulation solicitation display (CSD) between 22 and 27 days after their first offspring has hatched. This period could be used to investigate the acoustical preferences of female canaries. This non-invasive method respects the natural reproductive cycle and could be an alternative to the invasive method of estradiol implants.

SYLLABLE PHONOLOGY AND SONG SEGMENTATION: TESTING THEIR SALIENCE IN FEMALE CANARIES

By stimulating female common domesticated canaries with computer edited song stimuli, we investigated the salience of own breed phonology or song segmentation. These own breed acoustic parameters versus alien breeds and heterospecific ones were tested using copulation solicitation displays as an index of female responses. We found that females gain information about their own breed identity from both phonology and song segmentation. Border strain syllables or segmentation ensure high levels of responses, similar to those elicited by own breed ones. By contrast, harzer strain, wild canary and greenfinch phonology or segmentation elicited low levels of displays. The weaker reactions were recorded to harzer phonology. Processes involved in female recognition of multipartite songs are discussed and compared to those used by male oscines.

Studying Female Reproductive Activities in Relation to Male Song: The Domestic Canary as a Model

Abstract Birdsong in oscine birds serves both intrasexual and intersexual functions. The aim of this chapter is to contribute to a better understanding of how birdsong is involved in female reproductive activity using the domestic canary as a model. Some special song phrases containing bipartite syllables composed of abrupt frequency falls and short silences (sexy phrases) appear to be particularly efficient to elicit sexual responses. Females canaries seem predisposed to prefer sexy phrases even though early or adult acoustic experience can affect this phenomenon. Moreover, eavesdropping on singing interactions, previous reproductive experience, as well as physical condition may be involved in shaping females’ preferences. Repeated exposures to male sexy phrases during reproduction do not influence the development of nest building or egg laying but affect egg quality. From the sender perspective, the production of the complex sexy phrases needs particular skills from the peripheral motor level as well as the central nervous system level.

SEXUAL RESPONSIVENESS OF FEMALE CANARIES TO SONG BOUT ORGANIZATION

Recent experiments demonstrated that in oscine species, 1) Some special sequences of multipartite songs convey more sexual information than others and 2) Stimulus change or switching is often associated with intersexual interactions. We looked for an influence of these two song cues in common domesticated canaries. Female canaries were tested for their sexual copulation solicitation display (CSD) in response to the playbacks of different strings of song sequences from males of the same breed. In order to induce habituation, three monotonous strings were created: A.A.A.A.A.A; B.B.B.B.B.B and C.C.C.C.C.C. (repetition of the same song sequence). In order to manage disrupt of habituation by stimulus changes, four types of strings including two types of song sequences were created: B.B.B.A.A.A., A.A.A.B.B.B., C.C.C.B.B.B. and B.B.B.C.C.C. We found that a monotonous repetition of the same sequence leads to habituation when the sexual potency of the sequence is high (sequences A and B) and that song sequences may greatly differ in eliciting sexual displays (A >B>C). Subsequent stimulus change may elicit an immediate response recovery. But such a disrupt of habituation occurs only if a prefered sequence follows a non prefered one. We discuss prominent parameters that may have influenced female sensitivity and responsiveness to string organization in domesticated canaries.

Performance constraints and the production of birdsong

The role of physical and physiological constraints in determining the performance limits on the tempo and frequency bandwidth of birdsong was investigated. One series of experiments examined the mechanism by which a vocal mimic, the northern mockingbird (Mimus polygottos), copied the songs of other species with which it was tutored as a juvenile. Other experiments analyzed the motor basis of special canary (Serinus canaria) syllables eliciting sexual responses from females. In each case, the mechanism of vocalization was determined by measuring the respiratory dynamics and sound produced on each side of the songbirds duplex vocal organ, the syrinx. When mockingbirds copied the songs of other species the accuracy of their copy depended on the accuracy with which they reproduced the motor pattern used by the tutor species. Motor difficulty of various acoustic features was assessed by the accuracy of its copy. The high repetition rate, broadband canary syllables preferred by females required especially demanding bilateral motor skills. The results indicate that constraints on the rate of respiratory ventilation and bilateral syringeal coordination can set an upper limit on syllable repetition rate and frequency bandwidth. [Work supported by NIH and NSF.]