Until recently, some have argued, exacerbating the probrem, that birds started flyrng either by leaping up from the ground, or by gliding down from trees or cliffs. (Realistic dinosaur costume)This up and down dichotomy is unfortunate because it may be unnecessary, and because it stifles consideration of alternatives. one possible alternative melds arboreality with horizontal leaping. In this concept the gliding stage is skipped and birds learn to fly directly via interbranch leaps-some leaps being downward, others up, and some level, so in total the average is horizontal. we know that arboreal leaping is a viable life-style, because there are thousands of living branch-leapers. As for climbing theropods, they were uniquely preadapted for wings and tails of the avian kind. They were bipeds with short trunks and stiff-action vertical hind limbs that could not splay out to the side and support a flying squirrel or bat type of interlimb membrane. The only places available to develop airfoils were on the tail and forelimbs. (walking dinosaur costume)The ability to better orient the body and limbs into the best position for landing on branches would have been very valuable, since misses could result in injurious or fatalfalls. Indeed, tree-leaping primates of about this size suffer substantial mortality from such mishaps.
If the work of Caple et al. on leaping aerodynamics is correct, then they inadvertently explained much of how interbranch leaps of climbing protobirds could be developed into full-powered avian flight. (Realistic animatronic dinosaur)They believe that just a slight lengthening of forelimb and tail feathers would give theropod-protobirds greatly improved roll and pitch control. They thought this would help bring the mouth closer to insects-but it would have been just as good at helping swing the hind feet closer to a branch. The motions of the arms as they maneuvered the developing winglets also mimicked the flaps of power flight. As the feet gripped the branch, the hands would continue to help by grabbing on too. Further enlargement of the airfoils and of the forelimb muscles to better control them not only increased control, but started to lengthen the leaps by turning them into glides. As the wings and their power sources continued to enlarge, the protobirds started to power-fly. Now they could not only leap further, but they could start landing higher than where they took off-a tremendous advance in arboreal rapid transit. In this sense, powered flight probably developed from the frees up, not the ground up. Some more of this and you have full size, high-powered wings, of the stage at which we find Archaeopteryx.