. Cassell's natural history . sand tapering backwards; the tail very long, and the wings rather short. The bill isslender, awl-shaped, and has a ridge or keel on the upper part, and margins to the edgesof both mandibles at the middle. Tlic tarsi are long and strong, as is also the hinder toe,the claw upon which is considerably produced. The Wagtails run with great rapidity, and do not hop or require the aid of theirpinions in running. They can run on the surface of very soft ground without sinking, andover slippery jDebbles by the brooks without any unsteadiness. And when it is necessaryfor th
. Cassell's natural history . sand tapering backwards; the tail very long, and the wings rather short. The bill isslender, awl-shaped, and has a ridge or keel on the upper part, and margins to the edgesof both mandibles at the middle. Tlic tarsi are long and strong, as is also the hinder toe,the claw upon which is considerably produced. The Wagtails run with great rapidity, and do not hop or require the aid of theirpinions in running. They can run on the surface of very soft ground without sinking, andover slippery jDebbles by the brooks without any unsteadiness. And when it is necessaryfor them to change from rumiing to flying, they can easily take wing from either of thosesurfaces. The legs of these biirls are placed behind the centre of gravity of their bodies, as isthe case in all birds which run rapidlj^, in consequence of which they would have somedifficulty, in recovering themseUes by mere muscular exertion when they bring theirbills to the ground, as they must frequently do in picking up their food. But us. TlIK PIKI) ^VAf:TAIr„ JIudie remarks, the Unvi aie long in proportion to (lie size of tin- liirds; but theneck and bill, instead of being so long us to enable the latter to reacli tlie ground wliilc • MotiR-illii Alba. THK WAfilAILS, 213 the axis of the body is horizonta], so ihat the shoulders must dqi mucli wlicn llic bill isbrought to a level with tlic feet. A biid so formed would be verj- apt to tumble forwardsif it had not some means of working a couiitirpoise, and tluit eounterpoise is the ^Hien that is expanded and struck forward against the air, it acts in nearty the samemanner as a wing, and pulls the body of the bird backwards, so that the liead is raisedwith comparatively little effort. All birds that liave the same length of tarsi in propor-tion to that of the neck and bill, have a similar action of the tail; but as that structure,and also the habit of picking up fViod on a level with the feet, is more remarkable in
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Keywords: ., bookcentury1800, bookdecade1850, booksubjectbirds, bookyear1854
