Steamer Ducks: To Fly or Not to Fly

Abstract

Many extant bird species have independently lost the ability to fly. This phenotypic convergence involving the loss of an ancestral trait is apparent in steamer ducks (Tachyeres), a genus comprising four recently diverged species. Steamer ducks are currently in a transitional zone between flight and flightlessness, presenting a unique opportunity to study the evolution of flight loss while the transformation is still in progress. Dynamic and sporadic flight capabilities within and between the species provide valuable insight into the genotypic and morphological bases of avian flightlessness.