Vestigial wings and the evolution of flightlessness in Galapagos Island cormorants (Phalacrocorax harrisi)
Keywords: Vestigiality, flightlessness, Galapagos Island cormorants
McNab, B.K., 1994. Energy conservation and the evolution of flightlessness in birds. The American Naturalist, 144(4), pp.628-642. https://doi.org/10.1086/285697 (Links to an external site.)
The author examined the hypothesis that energy conservation contributes to the evolution of flightlessness in birds by comparing the factors correlated with basal metabolic rate in flighted and flightless rails and ducks. They found support for their hypothesis in flightless birds, except penguins, which use their wings for locomotion in water. This paper suggests that a lack of selective pressure for flight (lack of predators) combined with a high metabolic demand to maintain flight capability, contributes to vestigiality (reduction of wings and pectoral muscles) in environments where resources are limited.
(*) Lecture material that related to the research paper