Male phenotypes in the ruff. (Left) Independent ruff males interacting at a lek. (Right) A Satellite ruff male with pale ornamental feathers at a lek. Photos courtesy of Tom Schandy. Ruff males have ...

A single gene in the shorebird species known as ruffs controls the blood concentrations of testosterone in males, and this in turn affects their appearances and behavior. Three adult male Ruffs ...

There are three morphs in ruffs that differ in their appearance and mating behavior. Males of the aggressive Independents (left) have more testosterone in their blood than the other two morphs (a male ...