The reason why : $b a careful collection of many hundreds of reasons for things which, though generally believed, are imperfectly understood. A book of condensed scientific knowledge for the million
John Stuart Mill · en
Humming-birds are entirely limited
to the western hemisphere, where a particular species is sometimes
bounded by the range of an island, while others are more extensively
spread, the _Trochilus flammifrons_, common to Lima, being observed by
Captain King upon the coast of the Straits of Magellan, in the depth of
winter, sucking the flowers of a large fuchsia, then in bloom in the
midst of a shower of snow. Among the birds incapable of flight, which
rival the quadrupeds in their size, the intertropical countries of the
globe have their distinct species, presenting similar general features
of organisation, as the ostrich of Africa and Arabia, the cassowary of
Java and Australia, and the touyou of Brazil. In the arctic regions, we
meet with species peculiar to them, the _Strix laeponicus_ or Lapland
owl, and the eider-duck, an inhabitant of the shores, from whose nests
the eider-down is obtained. Several families of maritime birds are
likewise limited to particular oceanic localities. Approaching the
fortieth parallel of latitude, the albatross is seen flitting along
the surface of the waves, and soon afterwards the frigate and other
tropical birds appear, which never wander far beyond the torrid zone.
It thus appears, that, notwithstanding the great locomotive powers of
birds, particular groups have had certain regions assigned to them
as their sphere of existence, which they are adapted to occupy, and
to which they adhere in the main, though it is easy to conceive of
natural causes occasionally constraining to a migration into new and
even distant territories. Captain Smyth informed Mr. Lyell, that when
engaged in his survey of the Mediterranean, he encountered a gale in
the Gulf of Lyons, at the distance of between twenty and thirty leagues
from the coast of France, which bore along many land-birds of various
species, some of which alighted on the ship, while others were thrown
with violence against the sails. In this manner, many an islet in the
deep, after ages of solitude and silence, uninterrupted except by the
wave's wild dash, and the wind's fierce howl, may have received the
song of birds, forced by the tempest from their home, and compelled to
seek a new one under its direction.
[Verse: "There is a path which no fowl knoweth, and which the
vulture's eye hath not seen."--JOB XVIII.]