The role of wing length in the evolution of avian flightlessness

摘要: Flightlessness has evolved independently in at least 11 extant avian families. A number of hypotheses have been proposed to explain these transitions individual families, including release from predation on oceanic islands, energetic costs flight and use forelimbs for activities other than flying. Few studies sought explore factors common all families containing flightless species, which may the taxonomic distribution flightlessness. In this study, we found that eight contain both flighted species shorter wing lengths relative body mass their sister This result is not biased by taxon size. Models aerodynamics predict birds with relatively short wings pay a high cost flight. We suggest increased flying predispose evolve species. The various causes shortening among possibility future flightlessness are discussed.