Signaling function of the female supercilium and under-eye mark in the sexually dichromatic black-throated blue warbler
I am investigating how plumage traits in female Black-throated Blue Warblers act as ornaments, potentially influencing both female-female competition and male mate choice. Ornamentation occurs in males to attract mates and compete with rivals. However, few examples of female-specific ornaments are documented in birds with conventional sex roles. Female Black-throated Blue Warblers fight frequently with each other in both the wintering and breeding grounds. Additionally, males invest heavily in their social mates, and reproductive success for both sexes is primarily driven by the ability to raise multiple clutches within a single season, a collaborative effort. I am working at the Hubbard Brook Experimental Forrest measuring plumage traits on the faces of female Black-throated Blue Warblers. Our field crew collects data on reproductive success and parental investment for all pairs. Additionally, I am conducting a simulated intrusion experiment to test how plumage traits predict intrasexual aggression.
color Placement in males and females: Cross-taxa patterns
Natural selection is believed to favor dull, cryptic coloration to avoid predation while sexual selection favors bright, conspicuous coloration to attract mates. Thus, natural and sexual selection can be been viewed as antagonistic, with phenotypic appearance resulting from a tradeoff between the two forces. However, this relationship can be quite complex, with selective pressure differing between body regions. Despite generally being the less decorated sex, conspicuous female traits still occur at some frequency. It can not be assumed though that the tradeoffs between natural and sexual selection operate the same in males and females. I am conducting a study of color placement in male and female organisms across taxa to explore how differences in these tradeoffs result in sexual dichromatism in the organization of color in different body regions.
Leg feathers in the Bank swallow: morphology and potential functions
I am working in partnership with the Cornell University Museum of Vertebrates and the American Museum of Natural History to examine a group of brush-shaped feathers on the posterior side of Bank Swallow tarsi. These feathers and their orientation appear distinct to the genus Riparia and can be observed in both Bank Swallows and their closest relative the Pale Sand-Martin. All three members of the genus Delichon also exhibit tarsal feathering, another group within Hirundinidae. I am using electron microscopy to reveal the structural differences in leg feather structure between the two groups. Additionally, I am working to determine the potentially distinct functions driving the repeated evolution of leg feathers in swallows.
Mutual Ornamentation in the black-throated blue warbler
Both the male and female Black-throated Blue Warbler poses a white wing spot. This plumage trait has been found to signal individual quality in males. However, it remains unexplored in females. I am working with my collaborators at the Hubbard Brook Field Ornithology Program to analyze a long-term wing spot dataset to explore how this trait can predict mating behaviors. Specifically, we are examining how a within-pair imbalance in ornamentation can predict extra-pair mating, parental effort, divorce, and polygeny.