To determine whether a commercially available supplemental perch might encourage raptors to shift perching
away from the energized zone of a pole where wires are present, we quantified raptor use of a supplemental perch manufactured by Bird Power Line Protection, Ltd (Calgary, Alberta, Canada).
Conversely, small species may gain some protection from larger predators (larger dragonflies and birds) by flying and perching
close to the water's surface.
If the bird is flying instead of perching
, Sibley argues, the Cornell group's calculations of bird size no longer work.
During times of inactivity, a perching
site is not a retreat site in the classic sense because a perching
site is an open space.
Furthermore, rather than pointing forward as in a theropod or backward as in a perching
bird, the Archaeopteryx first toe pointed sideways as a human thumb does, says Mayr.