A new paper with suggested implications for the origin of flight in Mesozoic dinosaurs.
D.D. Chin and D. Lentink (2017)
How birds direct impulse to minimize the energetic cost of foraging flight
Science Advances 3: e1603041
DOI: 10.1126/sciadv.1603041
http://advances.sciencemag.org/content/3/5/e1603041Birds frequently hop and fly between tree branches to forage. To
determine the mechanical energy trade-offs of their bimodal locomotion,
we rewarded four Pacific parrotlets with a seed for flying voluntarily
between instrumented perches inside a new aerodynamic force platform. By
integrating direct measurements of both leg and wing forces with
kinematics in a bimodal long jump and flight model, we discovered that
parrotlets direct their leg impulse to minimize the mechanical energy
needed to forage over different distances and inclinations. The bimodal
locomotion model further shows how even a small lift contribution from a
single proto-wingbeat would have significantly lengthened the long jump
of foraging arboreal dinosaurs. These avian bimodal locomotion
strategies can also help robots traverse cluttered environments more
effectively.