Effects of Male Vocal Learning on Female Behavior in the Budgerigar, Melopsittacus undulatus

Abstract

Parrots are unusual among birds and animals in general in the extent of their ability to learn new vocalizations throughout life and irrespective of season. The budgerigar (Melopsittacus undulatus), a small parrot that is well suited for laboratory studies, has been the subject of numerous studies investigating the neurobiology of vocal learning. To date, few studies have focused on the function of vocal imitation by parrots. Previous work from our research group has shown that vocal imitation in budgerigars is sex-biased, as males paired with females learn vocalizations from their new mates, but not vice versa. This bias led us to hypothesize that vocal learning has a reproductive function. To test this hypothesis, we conducted two experiments. In the first experiment, we tutored males so that they could produce a call similar to one shared by a group of experimental females. The experimental females were then presented with one of the tutored males and another, equally unfamiliar, male that had not been tutored. We found that the females spent a greater proportion of time in proximity of, and made more affiliative displays toward, the tutored males. In the second experiment, seven males received small bilateral brain lesions that disrupt vocal learning. These males and an equal number of control males were then released into an aviary containing females and reproductive resources. We found that lesioned and control males were equally successful in obtaining social mates, but females mated to lesioned males were more likely to engage in extra-pair activities. These experiments indicate that a male's ability to imitate a female's call can influence the sexual behavior of the female even though lack of imitation ability does not appear to influence social pairing. We hypothesize that mate choice in budgerigars has multiple stages. Upon meeting a strange male, a female quickly assesses its ability for social acquisition of calls by the presence or absence of a call type similar to its own in its repertoire. As courtship proceeds into pair formation, the female assesses the ability of male to learn more directly by the extent of the male's perfection of imitation. Ethology 111, 901-923 (2005)

A test of multiple hypotheses for the function of call sharing in female budgerigars, Melopsittacus undulatus

“…Although both sexes can imitate the calls of other individuals, females do so more slowly, and when in male–female pairs, the males imitate the females’ calls (Hile et al 2000; Hile and Striedter 2000). Support for a sexual selection and/or pair-bonding function has been supported in male–female studies (Hile et al 2000; Hile et al 2005; Moravec et al 2006; Moravec and Striedter 2010), but since call sharing also occurs between same-sex individuals, it is likely that imitation serves additional functions beyond promotion of the pair bond. Our work supports the hypothesis that call matching may serve different function(s) depending on the social relationships between the individuals.…”

“…Call sharing in this species appears to exhibit different patterns depending on how groups are formed. In male–female pairs, males typically imitate female calls, and this process appears to contribute to pair bond formation and maintenance (Hile et al 2000; Hile et al 2005; Moravec et al 2006; Moravec and Striedter 2010). Imitation also occurs in all-male groups when immigrants are introduced to a new flock (Bartlett and Slater 1999; Young 2011).…”

Social calls provide novel insights into the evolution of vocal learning

“…Furthermore, the ability to learn new calls quickly or with greater fidelity could provide receivers with information about a signaller’s quality or other learning abilities (Boogert et al, 2011; Nowicki & Searcy, 2004). For example, female budgerigars prefer males that are tutored to produce imitations of the female’s calls before pairing, and females paired with brain-lesioned males incapable of learning engaged in more extrapair copulations (Hile et al, 2005). Whether call learning reflects affiliation, a male’s cognitive ability, or local knowledge is unclear, but female preference for vocal learning in budgerigars suggests that mate choice can provide additional selection for call learning, even if it was not the primary force driving its origin.…”

Ethology into a new era

“…2005), the functions of song as territorial signal and in mate choice and mate stimulation (Beebee 2004, Martin‐Vivaldi et al. 2004, Mota & Depraz 2004, Hile et al. 2005, Hyman 2005), and by comparative studies concerned with the evolution of vocal learning, song type repertoires and dialects (Handley & Nelson 2005, Nelson et al.…”