Wing-Assisted Incline Running and the Evolution of Flight

2003/01/16 by Kenneth P. Dial · 9 citations
Earth and Planetary Sciences · Environmental Science · Engineering · #Paleontology and Evolutionary Biology #Avian ecology and behavior #Biomimetic flight and propulsion mechanisms

paper · doi:10.1126/science.1078237

openalex publication_date 2003/01/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01

Abstract

Flapping wings of galliform birds are routinely used to produce aerodynamic forces oriented toward the substrate to enhance hindlimb traction. Here, I document this behavior in natural and laboratory settings. Adult birds fully capable of aerial flight preferentially employ wing-assisted incline running (WAIR), rather than flying, to reach elevated refuges (such as cliffs, trees, and boulders). From the day of hatching and before attaining sustained aerial flight, developing ground birds use WAIR to enhance their locomotor performance through improved foot traction, ultimately permitting vertical running. WAIR provides insight from behaviors observable in living birds into the possible role of incipient wings in feathered theropod dinosaurs and offers a previously unstudied explanation for the evolution of avian flight.

Citations

• Two feathered dinosaurs from northeastern China
• The wing of Archaeopteryx as a primary thrust generator

Cited by

• Mechanics of wing-assisted incline running (WAIR)
• Physical theory, origin of flight, and a synthesis proposed for birds
• The Predatory Ecology of Deinonychus and the Origin of Flapping in Birds
• The wings before the bird: an evaluation of flapping-based locomotory hypotheses in bird antecedents
• Assessing Arboreal Adaptations of Bird Antecedents: Testing the Ecological Setting of the Origin of the Avian Flight Stroke
• Evolution of avian flight: muscles and constraints on performance
• The asymmetry of the carpal joint and the evolution of wing folding in maniraptoran theropod dinosaurs
• Bird flight [wikipedia]
• Origin of birds [wikipedia]