rapidity of their utterance. I have often attempted to transcribe some
of their notes upon the musical scale, but I am persuaded that such
sketches can be only approximations to literal correctness. As
different individuals of the same species sing very differently, the
notes, as transcribed from the song of one individual, will never
exactly represent the song of another. If we listen attentively,
however, to a number of songs, we shall detect in all of them a
_theme_, as it is termed by musicians, of which the different
individuals of the species warble their respective variations. Every
song is, technically speaking, a _fantasia_ constructed upon this
theme, from which none of the species ever departs.

It is very generally believed that the singing-birds are confined to
temperate latitudes, and that the tropical birds have not the gift of
song. That this is an error is apparent from the testimony of
travellers, who speak of the birds in the Sandwich Islands and New
Zealand as singing delightfully, and some fine songsters are
occasionally imported in cages from tropical climates. The origin of
this notion may be explained in several ways. It is worthy of notice
that within the tropics the singing season of different species of
birds does not occur at the same time. One species may be musical in
the spring, another in summer, and others in autumn and winter. When
one species, therefore, has begun to sing, another has ceased, so
that, at whatever time of the year the traveller stops, he hears but
few birds engaged in song.

In the temperate latitudes, on the contrary, as soon as the birds
arrive, they commence building their nests, and become musical at the
same time. If a stranger from a tropical climate should arrive in this
country in the spring, and remain here during the months of May and