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CHAMBERS’S JOURNAL
OF
POPULAR
LITERATURE, SCIENCE, AND ART.
CONTENTS
BIRD MIGRATION.
BY MEAD AND STREAM.
ANCIENT ROCK-HEWN EDICTS.
A RUN FOR LIFE.
FAMILIAR SKETCHES OF ENGLISH LAW.
HEROINES.
ARMY SCHOOLS.
LIGHTING COLLIERIES BY ELECTRICITY.
A LAST ‘GOOD-NIGHT.’
No. 31.—Vol. I.
Price 1½d.
SATURDAY, AUGUST 2, 1884.
BIRD MIGRATION.
The migration of birds is a subject that hasexcited the attention of naturalists of all nationsfrom very early times, and many theories havebeen advanced to account for the mysteriousperiodical movements that take place among thefeathered tribes, although it can hardly be saidthere is one which fully explains these movements.Some writers affirm that they areentirely due to temperature; others, that theyare caused by a want of food; while others, again,assert that they are traceable, within certainlimits, to a hereditary impulse which guides birdsin following lines of flight over seas where at onetime all was land.
There can be no doubt that originally, birds,like other animals, were actuated to a greatextent in their periodical shiftings by the mainconsiderations of food and temperature. Asfamiliar examples of this, we have only toremember that species which are reared withinthe Arctic Circle are compelled to quit theirbirthplaces as soon as the brief summer is past—theirhaunts becoming wrapped in snow, andtheir feeding-grounds converted into a drearyexpanse of ice; while in our own country, everyone knows that swallows and other soft-billedbirds are obliged to leave us at the close ofautumn, and repair to climes where there isnot only greater warmth but abundance of insectlife, on which their subsistence depends.
Another theory, however, may be adverted to,as showing the phenomena in a more suggestiveand poetical light—namely, that put forward bythe aged Swedish poet Runeberg, who believesthat birds, in undertaking their vast and toilsomejourneys, are solely influenced by their longing forlight. When the days become shorter in thenorth, birds make up their minds to go southwards;but as soon as the long northern daysof summer set in, ‘with all their luminous andlong-drawn hours,’ the winged hosts return to theirold haunts. There is evidently something in thistheory, because, in the case of the insectivorousbirds, there is little diminution of fo