variation in the color, the surface showing an exquisitely delicate
tint which is but poorly expressed in our English term of light
purple-vinaceous. There are sometimes zones of lighter tint about the
larger or smaller end, due to some physiological cause in the lower
portion of the oviduct. I consider the color of _Crypturus_ eggs as
distinctly protective, much more so than those of _Tinamus_, whose
turquoise sheen is readily seen against the jungle débris. As such it
is at least one ameliorative factor in the risk of the small number,
and the danger of the continuously breeding male bird. The birds always
sit close however, and only when almost stepped on do they boom up and
away. Many an egg would go undetected if, instead, the sitting tinamou
would creep stealthily off at the first hint of danger. The gloss of
the egg is not quite as high as in _Tinamus_, but it is still far ahead
of any other bird’s egg with which I am familiar,--one of the most
beautiful shells in the world.
Out of the observation area I have known three eggs of the variegated
tinamou to disappear suddenly long before incubation was completed, but
only in one case do I know the cause, when a herd of peccaries trod
heavily over the nest and all the neighborhood, a few fragments of
yolk-stained shell showing how a single crunch had provided some wild
pig with a delicious mouthful.
Incubation lasts about twenty-one days, and I have two notes, one of my
own and the other by an assistant, of nests being deserted twelve hours
and twenty-four hours after hatching. The parent therefore has at least
the precocity of his offspring to lighten his labors. We have secured
two young birds of about two and five weeks respectively, feeding by
themselves at a distance from the parent, so the precocity extends
to the independent juvenile life, thus allowing the male to take up,
unhampered, a new round of domestic duties.
The position of the chick in the egg is very obviously an adaptation
to facilitate shell-breaking. The neck and head are folded close to
the breast and abdomen, while the right leg is raised far forward and
sideways until the beak rests directly on the under side of the flexed
tarsus. Pressure is thus brought to bear on the shell not only by
movements of the head but the slightest effort at extension of the foot
and leg automatically forces the beak in general and the egg-tooth in
particular against the inner wall of the egg-shell.
On June 9, 1922, a single egg of the variegated tinamou was taken from
a nest on the ground in the jungle. It was light purple-vinaceous with
the usual highly polished sheen, and as well as I could determine
through the dense pigmentation, the embryo was five or six days old.
The egg was placed in the incubator in a temperature of 100 to 103
degrees and dampened and turned regularly.
Sixteen days later the egg was pipped at ten o’clock in the morning.
Within two hours the chick was out, partially dried and creeping about
all over the incubator shelf. The down dried well, but not on the
back and head until I put in a circular band of flannel, into which
the chick crept and by rubbing around as it would under its parent’s
plumage, the dorsal down dried fluffily. There is no doubt that the
young bird would never dry well without the constant friction of the
old bird’s feathers during the first twelve hours after hatching. This
condition of the down is apparently a rather serious thing, for when
the down dries flat and matted together, it causes such irritation that
the little chick wastes much time and strength in trying to preen the
bad places. Even a slight thing like this might very well be a matter
of life or death, at a time when every moment of learning to correlate
eye and beak is of the utmost importance.
I observed that the banging of the incubator door caused instant fear
reaction--the chick squatting at once, but no other observations were
made until the following day at ten in the morning when it was taken
into the compound in a vivarium.
Placed on the ground the tinamou chick twice showed fear reactions,
then pecked of its own accord. I worked with it off and on all day, and
at last it took four small pieces of worms. On the whole it was far
less apt in learning to calculate distances than _Tinamus major_ of
equal age. This was so marked that I believe it to be another example
of very delicate balance between necessity and practice. In _Tinamus_
there is a single adult to look after a brood of six to ten, while the
solitary _Crypturus_ chick has the whole attention of its parent, so
there is far less need for extreme precocity in this case than in the
former. With only a single chick to look after, greater care will be
taken, and more time devoted to feeding and guiding the offspring. In
_Tinamus_ the young are compelled to forage more on their own, having
the disadvantage of only a fraction of parental solicitude.
Another characteristic peculiar to this species in comparison with the
larger tinamou is its relative silence. The other chicks, or even one
by itself, were always cheeping and calling, whereas this one uttered
only very low calls and at infrequent intervals. Even these are given
only when the bird is quiet and undisturbed, and seem to be more in
the nature of content calls then otherwise. It is readily seen that it
is important for a covey of chicks to keep in touch with each other by
frequent calls, whereas a single chick following its parent could with
safety do so in comparative silence.
The _Crypturus_ chick learned the use of its legs and by two o’clock
could make its quick, short spurts without falling over at the end. It
never walked slowly more than a step or two, but usually after several
futile pecks at the bit of worm which I proffered, if it heard a sudden
noise, it darted swiftly one or two feet away and squatted flat. I
tested it with various sounds and found I could cry out loudly or clap
my hands together near it without effect, but the least deep or hollow
sound such as striking the glass side of the empty vivarium, caused it
to jump and flatten. Its pecking, as in _Tinamus_, was always forward
and downward at the ground, and its constant fault was to strike
beyond the object aimed at. The chick was uncomfortable on a white
handkerchief and scuttled to bare ground as quickly as possible. It
pecked at worms and spiders much more readily on the ground, even when
they were of the same color as their surroundings, than when they were
laid conspicuously on light bamboo leaves or when held in the forceps.
I tried calls and whistles with no apparent effect, until I imitated
the note of _Crypturus_ itself. Like a flash the chick turned in my
direction, ran six feet toward me, and crouched beside my foot. I tried
it again and again, then summoned the members of my staff to watch. The
shrillest whistle brought no response, but the very first note on F
natural above middle C, attracted and held the little bird’s attention,
and the following notes brought it headlong. After such a reaction it
was much more alert and willing to attempt another bit of food, and not
only this, but its sense of direction was almost perfect. When I held
my face close to the ground and called, the chick ran, not only toward
me, but stopped at my mouth, although I had finished calling before it
reached me.
This instinctive and perfect reaction to the call of the species,
together with its disregard of the call of _Tinamus_ and other
terrestrial jungle birds, was wholly unexpected. I have known chicks of
other groups to crouch instinctively at the cry of a hawk, or the alarm
note of their own or other birds, but to recognize among many other
imitations, the exact summons call, was very interesting and threw a
new light on the instinct reactions of this very generalized type of
bird.
It did not enjoy being in the hot sun, but ran with quick darts toward
the shade. Like the other tinamou chicks it never showed the slightest
fear of our enormously tall figures stalking about. In fact, if anyone
passed while I was attempting to induce it to eat, it invariably rushed
off and followed, and had to be brought back and started over again in
food interest. Unlike the large _Tinamus_ chicks no shuffling of hands
or feet in scratching motions and sounds had any effect.
Like so many of the small creatures I have watched in the laboratory
compound, the chick persisted invariably in working toward the east or
northeast. Again and again I turned it about and always it changed
direction and started back. I place no special significance at present
upon this, but present it as an interesting fact as applying to
mammals, birds, reptiles, amphibians and even to armored catfish. When,
however, I gave the parent’s call the chick never failed to turn and
run toward me regardless of direction.
While it learned to peck and swallow bits of food and quartz with fair
accuracy, I could not give it the constant attention and encouragement
which it needed, and it died on the third day.
For many years the tinamou was a glorious anticipation--a hope
engendered by the accounts of travelers in the tropical wilderness. It
is now not only a memory but a stimulation, for when the city presses
too closely, when four walls suffocate as well as enclose, when people
oppress as well as associate, then I go to the bird house at the
Zoological Park and at five o’clock there seldom fails me a sweet,
clear staccato of silvery tones. Body and soul, I am back in the Guiana
jungle, with the cool night settling down, a distant howler clearing
his throat, and a bass chorus of giant tree frogs rumbling across the
river. Then the tinamou calls again and the world is reorientated.
TRANSCRIBER’S NOTES
The chapter numeral in the chapter headings for Chapters VIII and IX were
missing in the original edition. The omission has been retained.
Page 105: corrected misspelled “inexplicaable”, and corrected misplaced
period after “center of the back” to a comma.
Page 151: corrected misspelled “aboreal”.
Page 183: corrected misspelled “emminently”.
Illustrations have been moved to enhance readability. The original page
numbers in the list of illustrations remain unchanged.
All other inconsistencies, particularly in hyphenation and diacritics,
have been left unchanged.