Does breeding bird density drive vocal individuality?

Abstract

Many species produce individually specific vocalizations and sociality is a hypothesized driver of individuality. Previous studies of social variation focused on species that were colonial nesters or not, and social group size in sciurid rodents. If sociality is an important driver of individuality, we might expect that species that defend nesting territories in higher density neighborhoods should have more individually-distinctive calls than those that defend nesting territories in lower-density neighborhoods. We used Beecher’s information statistic to quantify individuality, and we examined the relationship between nesting density and vocal individuality in Lincoln’ sparrows, Melospiza lincolnii, and mountain white-crowned sparrows, Zonotrichia leucophrys oriantha. We conducted point counts to examine the relative density of each species at our site and conducted a literature review to examine relative densities of each species at other sites. We found that mountain white-crowned sparrows exhibited a significantly greater degree of individuality within their songs than did Lincoln’s sparrows. While there was no difference in density of the two sparrow species at our study site, the literature review suggested that the relative density of white-crowned sparrows is typically greater than Lincoln’s sparrows. From this we conclude that white-crowned sparrows are generally more social than Lincoln’s sparrows, and that, as predicted, they have a greater degree of individuality in their vocalizations. Thus, we suggest that bird species nesting in denser aggregation exhibited a greater degree of vocal individuality. With further work, it may be possible to use Beecher’s information statistic as a potential predictor of breeding bird densities. Key Words Individuality; Sociality; Birdsong; Lincoln’s sparrow; White-crowned sparrow

Local Knowledge Graph (9 entities)

Related Works

Items connected by shared entities, co-authorship, citations, or semantic similarity.

References (24)

1 in Knowledge Hub, 23 external