PARENT SESSION
Contributed Oral Session 18: Avian Communities and Populations
Monday, August 8, 8:00 AM - 11:30 AM, Meeting Room 524 C, Level 5, Palais des congrès de Montréal
Song repertoire size and male quality of song sparrows, Melospiza melodia.
Pfaff, Jeremy*,1, Zanette, Liana1, MacDougall-Shackleton, Scott1, 1 University of Western Ontario, London, Ontario, Canada
ABSTRACT- In many songbird species, females prefer mating with males with large song repertoires. The nutritional stress hypothesis states that males who have experienced less severe developmental stress or who are innately more resilient to such stress are able to devote more resources to the development of song control nuclei and are, therefore, capable of acquiring larger, more complex song repertoires. Consequently, a functional explanation for the female preference for large song repertoires is that males with large song repertoires have faired better during early development, and are genotypically or phenotypically high quality individuals capable of conferring more indirect and direct benefits to the female. If this hypothesis is correct, then song repertoire size should correlate positively with several morphological and physiological indices of individual quality in male songbirds. In this study, we test the hypothesis that song repertoire size is indicative of male quality in the song sparrow, Melospiza melodia, a species for which a female preference for large repertoires has been demonstrated in both field and laboratory studies. Previous studies concerning ornamental male traits as quality indicators have reported conflicting results, with some studies reporting positive correlations between male ornaments and indices of male quality, and others reporting no significant relationship. These studies, however, often measure male quality based on very few morphological or physiological variables, which makes the validity of these measures ambiguous. Here, several independent indices of male quality were obtained, including morphometrics, measures of body condition and physiological profile, from a breeding population of 60 pairs of song sparrows in southern Ontario over three consecutive field seasons. Analysis of preliminary data revealed a significant positive correlation between song repertoire size and male body condition. These results provide supporting evidence for the hypothesis that song repertoire size acts as a cue for male quality.
Key words: mate choice, song repertoires, male quality, Melospiza melodia