170 
BIRD-LIFE. 
that portion of the plant-world which is productive of 
fruits, seeds and insects, is evident. If we extend the 
sphere of observation, an undoubted regularity in that 
distribution soon becomes apparent; and this is inti¬ 
mately connected with the nature of the soil and the 
climate. The resemblance between birds and certain 
districts is striking; we remark, even, that the con¬ 
formity of animals with the localities which they 
inhabit is not confined to level circuits alone, but is 
analogously manifested in high-land districts. 
Thus, if we would observe the gradual changes of 
certain species, it is almost immaterial whether one 
wanders from Germany northwards, or climbs from a 
valley to the snows of an alpine range. On both roads 
we leave behind us, by degrees, oak, beech, pine, and 
birch, until the plant-world is only represented by a 
few mosses and other low forms, and at last vanishes 
almost entirely. In both cases we alike lose sight of one 
bird after another, though, here and there, a new species 
crops up, which, if not identical with, is one which corre¬ 
sponds to, and, as it were, replaces it. Little Owls, 
Pipits, Thrushes, Blackbirds, Wagtails, Redstarts, Robins, 
Warblers, and others, are found at higher elevations and 
latitudes respectively, both in corresponding degrees; till 
in the one case, the Snow Bunting (Emberiza nivalis ), and 
in the other, the Snow Finch ( Fringilla — Montifringilla — 
nivalis ), together with the Ptarmigan, common to both, 
are the sole representatives of bird-life on land. 
In wandering through more extended regions, we 
recognize a gradual disappearance of the different 
species, though we see these replaced again by other 
forms. There are very few birds, indeed, which are to be 
met with distributed over the entire globe, and those that 
