The Plumage Bill

The evolution of bill coloration and plumage dimorphism supports the transference hypothesis in dabbling ducks

Bright coloration in male birds is typically thought to be driven by sexual selection (female choice or male–male competition). Bird species often vary in the intensity of bright coloration, but few studies have addressed this cross-species variation. Potentially this variation could result from either variation in female preferences or in the relative costs of male traits. Species of dabbling ...

Blood parasite infection differentially relates to carotenoid-based plumage and bill color in the American goldfinch

Male and female American goldfinches (Spinus tristis) express condition-dependent carotenoid-based plumage and bill coloration. Plumage color is relatively static, as pigments incorporated into feathers during the spring molt cannot be mobilized thereafter. In contrast, bill color is dynamic, reflecting changes in condition over short time periods. Previous studies have shown that male and fema...

Differentially expressed genes match bill morphology and plumage despite largely undifferentiated genomes in a Holarctic songbird.

Understanding the patterns and processes that contribute to phenotypic diversity and speciation is a central goal of evolutionary biology. Recently, high-throughput sequencing has provided unprecedented phylogenetic resolution in many lineages that have experienced rapid diversification. The Holarctic redpoll finches (Genus: Acanthis) provide an intriguing example of a recent, phenotypically di...

Within-male melanin-based plumage and bill elaboration in male house sparrows.

If there is a cost to producing a dark color patch, the size of a patch may not correspond with its pigment concentration. The plumage of male house sparrows represents a case of dark, melanin-based ornamentation, but also a case of neglecting the composite nature of dark signals in birds. Here, I investigated what kind of associations exist between the brightness, chroma, and hue of dark integ...

The Drug Control Bill