. The bird, its form and function . on of the foot whichwe usually call the leg, is, in almost all birds, covered withhorny scales, yet these vary con-siderably in different groups. Inmany the scales are small, six-sided or oblong, as in some of the higher song-birdsthese scales have become joinedtogether until, as in our robin,the front of the leg is coveredwith a long boot of cause of this coalescence yetremains to be discovered. A considerable degeneration ofthe legs and feet is found among goatsuckers, humming-birds, and chimney swifts; but, small as are the feet ofthe
. The bird, its form and function . on of the foot whichwe usually call the leg, is, in almost all birds, covered withhorny scales, yet these vary con-siderably in different groups. Inmany the scales are small, six-sided or oblong, as in some of the higher song-birdsthese scales have become joinedtogether until, as in our robin,the front of the leg is coveredwith a long boot of cause of this coalescence yetremains to be discovered. A considerable degeneration ofthe legs and feet is found among goatsuckers, humming-birds, and chimney swifts; but, small as are the feet ofthe latter birds, they make frequent use of them to breakoff the short twigs which are used in the constructionof their nests. One may take a young swift and place itagainst the vertical surface of an ordinary brick (Fig. 326),and the bird will hold fast without slipping a fractionof an inch. The slender nails fasten in the slightestirregularity of the surface and hold the bird safely. Some species of swifts have all four toes pointing. Fig. -Foot of AmericanPipit. Feet and Legs 369 forward, forming a four-tined grapple by which theyhang themselves up in their hollow nesting-trees. Whip-poorwills and some other birds have a curious comb,or pecten, along the edge of the middle claw, which isperhaps of use in cleaning the long bristles about theirmouths, or in arranging their very delicate, soft and several related groups of birds make solittle use of their feet, except in motionless perching, that
Size: 1431px × 1747px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectbirds, bookyear1906
