he young male, even before its testicles have
developed, woos the female by movements, song, or other characteristic
sounds. The female, also sexually immature, responds coquettishly to
these advances of the male. Song, which Brehm regards as a sign of the
awakening of love, makes its appearance at an age when the animal is
still unfitted for the reproductive act.

"Young magpies (_Corvus pica_) address one another in September, and
often in August and in October, in consecutive clucking notes, and in
this way make exactly the same kind of noise that they are always heard
making in early spring just before the pairing season. The young male
green woodpecker (_Picus viridicanus_) sings in September as beautifully
as in April, as I have myself heard more than once; the young great
spotted woodpecker (_Picus major_) may even be heard at times in autumn,
just as in spring, making his characteristic tapping sound as he
explores hard branches in search of insects. Both varieties of creeper
begin to sing before they have changed their youthful plumage; their
song closely resembles that of the adult birds in spring, but the note
is somewhat shorter and weaker. Similarly, both the German varieties of
crossbill commonly begin to sing before losing the plumage
characteristic of youth. Young house-sparrows and hedge-sparrows not
only chatter and swear at one another like the full-grown birds at
pairing time, but also like the latter the young birds distend their
throats, let their wings droop, peck at one another, and in fact behave
as exactly as they will next spring when fully grown. Young linnets also
begin to sing before losing their youthful plumage, learn to sing well
during the moulting season, and often continue to warble right on into
the winter; in a mild winter young linnets will sing just as well as old
ones. The young woodlark begins to sing as soon as its first moulting is
nearly over, and not only does this when perching, but flies aloft like
the adult bird in the spring-time, and soars for a long time, singing
continually. Titmice all sing when still quite young, but more
especially the large crested titmouse and the marsh titmouse; the notes
of the young marsh titmouse are precisely similar to those with which in
spring the adult bird sings to his mate; and as regards the crested
titmouse, in October 1821, I observed a young male bird making advances
of a most marked character to a young hen, whilst the hen drooped