How a Red Bird Revolutionized Sexual Selection Science
When Dr. Geoffrey E. Hill received the 2014 William Brewster Memorial Award, it crowned a decades-long investigation that answered one of evolution's most persistent questions: Why are some male birds so beautifully colored?
Explore the DiscoveryThrough ingenious experiments with a common backyard bird, Dr. Geoffrey E. Hill transformed our understanding of sexual selection, animal signaling, and the evolution of beauty itself.
His research with the House Finch provided crucial evidence that female choice serves as a powerful evolutionary force, driving the development of extravagant male traits.
Recognizing exceptional body of work on birds of the Western Hemisphere
Presented annually by the American Ornithologists' Union, the William Brewster Memorial Award recognizes the most exceptional body of work on birds of the Western Hemisphere.
Professor of biological sciences at Auburn University, Hill received the 2014 Brewster Award for his decades-long investigation into why some male birds are so beautifully colored.
Hill's work answered one of evolution's most persistent questions through ingenious experiments with a common backyard bird, transforming our understanding of sexual selection.
Originally a desert species of the Southwest, House Finches had colonized eastern cities and become familiar backyard visitors. The males sported striking red coloration on their heads, throats, and chests, but with a crucial variation - some were vivid crimson while others appeared pale orange or yellowish.
Hill recognized this natural variation as the perfect natural experiment waiting to be explored.
Hill established what would become one of the model systems for studying female mate choice and sexual selection 1 .
His pioneering research demonstrated that the intensity of a male's red coloration directly predicted his mating success - females consistently preferred the reddest males available 1 .
Female mate choice relative to male plumage color based on Hill's research
The answer lay in carotenoids - organic pigments that finches cannot produce themselves but must obtain from their diet of berries, seeds, and fruits.
Hill hypothesized that only the highest quality males could secure sufficient carotenoid-rich food to produce vibrant plumage while also maintaining robust health.
He devised an elegant series of experiments using what colleagues termed "designer finches" - birds with carefully manipulated diets and plumage coloration 1 .
| Group | Dietary Carotenoids | Number of Males | Plumage Outcome |
|---|---|---|---|
| Control Group | Natural levels | 15 | Pale red to orange |
| Low Supplement | Moderately enhanced | 15 | Medium red |
| High Supplement | Significantly enhanced | 15 | Vibrant crimson |
Hill's research demonstrated that carotenoid pigmentation functioned as an honest signal of male quality. Only robust, healthy males with efficient immune systems and superior foraging abilities could divert sufficient carotenoids to produce brilliant plumage, as these pigments are also critical for immune function 1 .
Hill's Nature paper on carotenoid-based plumage coloration became a classic in the field, cited hundreds of times and helping spawn an entire research area exploring the connections between pigmentation, immune function, and sexual selection 1 .
Using spectrophotometry to quantitatively measure color intensity and hue, replacing subjective visual assessments with precise numerical data.
Carefully controlled diets with varying carotenoid supplements to establish cause-effect relationships between nutrition and coloration.
Introducing controlled immune challenges to assess how coloration predicted disease resistance capabilities.
Controlled behavioral observations where females could choose between males of different coloration in naturalistic settings.
This multifaceted approach allowed Hill to move beyond correlation to establish causation in the relationship between diet, color, and mating success.
While Hill's work on House Finch coloration formed the core of his Brewster Award recognition, his scientific contributions extended far beyond this system.
Scientific Publications
Citations
| Research Area | Key Findings | Significance |
|---|---|---|
| Sexual Selection | Female mate choice drives evolution of male plumage | Established mechanism behind ornamental traits |
| Carotenoid Coloration | Color signals health and foraging ability | Linked diet, immune function, and mating success |
| Plumage Biochemistry | Identified specific carotenoids and metabolism | Revealed physiological basis for color variation |
| Species Recognition | How closely-related species maintain boundaries | Informed understanding of speciation processes |
The 2014 William Brewster Memorial Award recognized not just a single discovery, but a fundamental shift in how we understand the evolution of beauty in the animal kingdom.
Geoffrey Hill's work demonstrated that what we perceive as mere beauty actually represents a sophisticated communication system developed through millions of years of evolutionary pressure.
The brilliant red of a humble finch had illuminated fundamental truths about nature's most selective force - the color of desire.
References to be added manually.