The form and function of song in female birds

Although female songbirds in temperate regions of the world sing less frequently than males, the songs of females may be highly functional with unique evolutionary histories and important fitness consequences. In collaboration with researchers at the Cornell Lab of Ornithology and elsewhere, our lab has been working to increase documentation of female song and to study how this communication signal has evolved differently in diverse lineages. Research related to this project has examined female song evolution in New World warblers, female song function in wrens and female song prevalence across all avian species.

Read about this research in The Washington Post or How Stuff Works. Listen to Lauryn discuss it on NPR's Science Friday or the American Birding podcast.

Habitat use, social behavior and communication among cliff-associated wren species of the Colorado Front Range

Canyon wrens (Catherpes mexicanus) and rock wrens (Salpinctes obsoletus) coexist in the rocky cliffs of northern Colorado and exploit similar ecological niches. We are conducting research to understand how they use resources, how they partition (or fail to partition) space, and how they communicate interspecifically and intraspecifically.

   

Click here to listen to canyon wren female and male songs recorded in Larimer County, Colorado. Click here to listen to a series of rock wren songs recorded from a male just outside of Fort Collins, Colorado. 

Read about our research in The Loveland Reporter Herald, or Northern Vision, and see our academic publications here. 

Song and duet form and function among New World sparrows

Ongoging projects are examining vocal divergence aacross the sagebrush/Bell's sparrow hybrid zone in the western United States, vocal characteristics of spotted towhees at two time points across an urban gradiant, and the evolution of vocal duets in genera, including Aimophila and Melozone. WIth all of these studies we are asking questions about how different evolutionary processes and pressures can shape vocalizations used in different contexts.

Song evolution in the genus Cisticola

This research asks questions about the evolution of vocalizations, including solo song and duets, within a large group of old-world species. By combining behavioral, ecological, geographic and phylogenetic information, our research takes a synthetic approach to understanding how evolutionary processes generate avian trait diversity.The genus Cisticola presents an excellent study system for examining patterns of song evolution because it includes nearly fifty species with distinctive vocal traits and varied levels of relatedness. Morphological traits are extremely conserved among cisticolas but song traits vary widely, suggesting an important role for song in maintaining species boundaries. Initial results support the assumption that cisticola songs are species-specific. Nevertheless, songs may be highly variable. Our analyses examine how both song form and song variability evolve.

Singing together: California towhee vocal duet function

This research investigated the functional significance of vocal communication behaviors among California Towhees (Melozone crissalis). Early studies established the social and ecological context of communication behaviors in order to better assess the function of vocal signals. California towhees are highly sedentary and exhibit life-long social pair bonds. As a result of this sedentary life-history, most individual vocalizations are not used to establish territory or attract a mate, differentiating California towhees from the majority of species that serve as models of bird song evolution. One uncommon vocalization type employed by California towhees is a duet performed by social mates. Duetting behavior is thought to exist in less than 3% of bird species, and is interesting because the highly coordinated nature of the signal suggests that it has been favored by a process of natural selection acting on two individuals simultaneously. Experimental playback and male removal studies have indicated that California towhee duets serve multiple functions, including coordination of pair-based activities such as defending resources and raising offspring. Successful offspring production is a critical determinant of evolutionary success, and experiments have indicated that California towhees of both sexes are highly attentive to offspring distress signals. Surprisingly, in light of their strong paternal care, social pair-bonds and duetting behavior, California towhees are not genetically monogamous. A molecular genetic analysis of parentage indicated that 42% of nests in one study population contained extra-pair young. This represents the first demonstration of frequent extra-pair paternity in a duetting species.