of the meadow, as
Master Song Sparrow so often chooses to do? Then he simply needs to
set his tongue and throat to quivering, and you have his enrapturing
tremolo. Beautiful, is it not?

There are birds that send a kind of guttural sound from their throats,
such as the cuckoos and occasionally the blue jays. Notice the cuckoo
as he utters his call, which every swain interprets as the harbinger of
a coming shower, and you will observe that his throat bulges out like
that of a croaking frog, and quivers at the same time in a convulsed
way. It is plain that the air about to be forced from the glottis is
flung back by some muscular action and set to vibrating in the
laryngean cavity, thus giving the sound its croaking quality when the
elastic current is finally released.

Now, if the reader will pucker up his lips and whistle a tune, he will
notice that the sound is actually produced at the small labial orifice
and nowhere else; however, the tones are modified and modulated at will
in a variety of ways--by a deft, though almost imperceptible,
manipulation of the tongue, by a slight enlargement or contraction of
the aperture, and especially by a dexterous control of the air column
blown from the lungs. Just so the lyrists of fields and woods pipe
their roundels and _chansons_ through the chink in their throats, save
that in the bird's case the mouth and tongue are anterior to the
whistling aperture. I know a young man who has trained himself so as
to be able to mimic to perfection the complex songs of the western
meadowlark and the cardinal grosbeak. He does it by whistling.

Near the lower end of the trachea, just above the lungs, there is a
specialized organ of the bird's throat called the syrinx. It is a
cylinder formed of bony rings, provided with a mesh of muscles, and
having membranous folds which act as valves upon the two orifices of
the _bronchi_ leading to the lungs. Many scientific gentlemen have
declared that the syrinx is the voice organ of the birds, the elastic
margins of the folds or valves being set to vibrating by the projection
of the air from the lungs, and thus producing the varied lays we hear
in the outdoor concert. However, Mr. Maurice Thompson--who, by the
way, found time to do something else besides writing "Alice of Old
Vincennes," and something just as creditable to his talent,
too--dissected many birds with special reference to this subject, and
gave close attention to birds in the a