BBC: Adult
birds will often flap their wings and run up steep inclines
rather than fly over them. Brandon Jackson of the University of
Montana wanted to know why birds capable of flight use the
flap-run motion, writes Victoria Gill for the BBC. To measure
birds' muscle activity, Jackson and his colleagues implanted
electrodes into the flight muscles of pigeons. They found that,
for birds, running up a ramp with a 65-degree incline requires
about 10% as much power from the flight muscles as flying.
Flap-running is also a crucial step in learning to
fly—young birds that can't fly yet due to small or weak
wings use it to get off the ground and away from predators,
transitioning gradually to full flight as they mature. Jackson
deduced that dinosaurs with similarly small, weak wings could
have also flap-run and transitioned toward flight over
evolutionary time.
