. L'oiseau, sa forme et sa fonction . Figure 257.—le oiseau de chat nichée, se soutenant, comme le lézard, sur les quatre membres. Plumage, fait la même chose, et les oiseaux de manyespèce 3oung, quand ils sont trop 3oung pour se tenir, poussent le sol avec des pieds et des ailes; un jeune grebe doutessétant le plus accompli dans ce mouvement. Chez les oiseaux adultes, comme le cygne, Osprey, la Vulture de la Turquie, et les divers oiseaux de type autruche, il y a un clawsat parfait les bouts d'un ou plusieurs doigts d'aile liés à la peau.ce sont de véritables reliques d'une ascendance gauchrée. Avant de continuer à trouver les utilisations plus curieuses

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. The bird, its form and function . Fig. 257.—Nestling Catbird, supporting itself, lizard-like, on all four limbs. plumage, does the same thing, and 3oung birds of manyspecies, when too 3oung to stand, push themselves alongthe ground with feet and wings; a young grebe doubtlessbeing the most accomplished in this motion. In certainadult birds, such as the swan, Osprey, Turkey Vulture, and the various ostrich-like birds, there are perfect clawsat the tips of one or more of the skin-bound wing-fingers.These are true relics of a lizard-handed ancestry. Before going on to find the more curious uses to which w ings 323 wings are put, we will look at certain birds whose flightcan teach us something niteresting. If a pheasant incaptivity becomes suddenly alarmed, or its spacious aviarytempts it to rise from the ground, we hear a great whirr, —broad, round-curved wings buzz in a half-circle of hazearound the bird and it is off like a shot to the farther. Fig. 25s.—Young Green Heron, reaching out with its wing toward a branch whichit hooked with the sprouting feathers, and steadied itself for a new foothold. end of the runway. It may go right through the sashand pane of glass—such is the impetus gained in this madrush. Fortunate it is for these birds, and for their cousins, tne grouse and quail, that they can thus spring up andescape from foxes and other enemies to whom their scentso often betrays them. If the pheasant were at liberty, 324 The Bird we should see that this burst of speed would end ina long, slowly descending sail, and with wings held mo-tionless the bird w^ould sink into the nearest cover. It ismost interesting and exciting to walk through a fieldof tall grass where many pheasants are feeding, and seethem shoot up to the right and to the left; a hen withher brood waiting until ones foot is almost upon herbefore booming away. In a zoological park we may observe another extremeof bird flight by watching a condor take w

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