Animal life in the sea and on the land . Preening.—The neck of birdsis always long enough to allow thebeak to reach an oil-gland whichis situated at the end of the tail,and which supplies the oil forpreening the feathers. The tailcan also be raised part way to meetthe beak, and the bird, having thusobtained a supply of oil from thegland, passes its feathers one afteranother through its bill in sucha way as to distribute the oilthrough the piumage. This processof preening smooths the feathersso that the bird may glide easilythrough the air or water, as thecase may be, and it also serves tomake
Animal life in the sea and on the land . Preening.—The neck of birdsis always long enough to allow thebeak to reach an oil-gland whichis situated at the end of the tail,and which supplies the oil forpreening the feathers. The tailcan also be raised part way to meetthe beak, and the bird, having thusobtained a supply of oil from thegland, passes its feathers one afteranother through its bill in sucha way as to distribute the oilthrough the piumage. This processof preening smooths the feathersso that the bird may glide easilythrough the air or water, as thecase may be, and it also serves tomake the plumage water-proof. 25. The Migration of Birds.—Butfew birds remain constantly in theplaces where they are birds unite in flocks andtake long journeys at certain sea-sons, leaving cold countries at theapproach of winter and returningin the spring, thus making twojourneys each year. It is an interesting fact that theyalways make their nests and raise their young broods inthe coldest countries which they Fig. 165.—Parts ofFeathkr. a, qnill; b, shrift; c, vaid, down. 252 ANIMAL LIFE IN THE SEA AND ON THE LAND. 26. In these migrations all the birds of one species seemfilled with an impulse to move in one direction in searchof food or other favorable conditions. Each kind has itstime for starting, and seldom varies from it. They some-times return the following season to the exact spot theystarted from, having in the mean time travelled hundredsof miles. The sea does not stop them, but they oftentake long flights over its surface, as, for instance, in cross-ing the Mediterranean Sea from Europe to Africa, or inofoins: from our own coast to the Bahama Islands and toSouth America. 27. Birds Useful in destroying Insects.— Many of thesmaller birds, which in former times were killed or fright-ened off because they robbed our gardens and orchards,are now considered useful in destroying insects, and gar-deners are doing what they can to invite their re
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1887
