Shan States, we have two dominant types of eggs: One blue, much
darker in tint than those referred to as being deposited in
_Leiothrix_ nests, laid with the similar eggs of the Burmese dark
gray bushchat (_Rhodophila ferrea haringtoni_), and the other
having a pale pink ground, freely blotched all over with reddish,
deposited in the nests of the Burmese stonechat (_Saxicola caprata
burmanica_), which also lays eggs of this color and character. In
connection with these two types of egg an interesting state of
affairs has now been arrived at in parts of the Shan States. Thirty
years ago the bushchat was extremely common in certain districts
in hills between 4,000 and 5,000 feet, and the great majority of
cuckoos found there were those laying blue eggs. Cultivation has
now wiped out the scrub and bush jungle, beloved by the bushchat,
and fields of rice, gardens, and the vegetation surrounding
villages have taken its place. With this change in the character of
the jungle growth has also come a change in the birds frequenting
it, the bushchat has almost disappeared, and the little stonechat
has taken its place, breeding everywhere in gardens, village
grounds, and cultivated fields. The elimination of the bushchat,
although so recent, has already gone far to eliminate also the
cuckoo that lays blue eggs, while the one that lays eggs like those
of the stonechat has become much more numerous and has become the
common form. Even now, however, an occasional blue egg of a cuckoo
will be found in the stonechats’ nests, the latter similar in every
respect to the nests of the bushchat and therefore cuckolded,
_faute de mieux_, by the cuckoo.
It is impossible here to deal with the problem of the evolution of
the various types of cuckoos’ eggs, but the facts recorded above
seem to go far toward proving that cuckoo eggs, to assimilate with
those of their fosterers, have been evolved by discrimination among
the foster parents leading to the slow but sure destruction of the
unfit, i. e., Darwin’s doctrine of the survival of the fittest in
its crudest form.
In shape the eggs are rather broader ovals than those of the
European cuckoo, and they also average larger and heavier. It is
indeed much easier to separate the various subspecies of cuckoo by
the eggs they lay than by the plumage of the birds that lay them.
The number of eggs laid by the Khasia Hills cuckoo probably varies
somewhat individually, though I believe it generally to be 12 to
20. It is, however, very difficult to decide this definitely, as
it is impossible to be satisfied that every nest of the selected
fosterer in any given area has without doubt been marked down. It
was not until 1907 that I concentrated on the attempt to solve
any one of the numerous cuckoo problems, and it was some years
after this before satisfactory evidence had accumulated on this
particular point. My different series of eggs of individual cuckoos
vary greatly in number, being, I believe, governed entirely by the
number of nests of the foster parent available in the area searched
over. In 1908, on May 25, in one small grass glade surrounded by
pine forest I found five nests of _Cisticola_, three containing
young cuckoos or eggs of the cuckoo, and I am practically sure that
I missed no _Cisticola_ or _Suya_ nests. One of these nests had in
it a young cuckoo about 2 days old, another nest had a young cuckoo
just hatching, while a third had a slightly incubated cuckoo’s
egg. The two other nests of the _Cisticola_ were unfinished and
empty, but on June 1 one of these contained a slightly incubated
cuckoo’s egg and three of the foster parent, while, finally, on
June 4 the last nest contained a fresh egg of the cuckoo and four
of the warbler. As the egg from which the older of the nestling
cuckoos had been hatched must have been laid about May 13, while
the last egg was laid on June 3 or 4, we have only five eggs
laid in 21 days, whereas we know now that the larger cuckoos lay
every second day, so the five eggs and the two young found cannot
possibly include all then laid. A series of 14 eggs, all found
between May 19 and June 10, 1910, in a similar but much larger
area, were probably laid between May 16 and June 10 and represent a
complete series laid every alternate day. In another small series
of five eggs of one and the same cuckoo found in a narrow strip
of grassland three eggs were deposited in Cisticola’s nests on
May 16, 18, and 20, this exhausting all the nests then available.
After this she apparently departed, but on July 5 and 7 the same
cuckoo returned and placed two more eggs, one each in two new nests
of Cisticolas. Another series of 14 eggs, of which 12 were placed
in nests of _Cisticola jundicis cursitans_, one in a nest of _C.
exilis tytleri_, and one in a nest of _Suya atrogularis khasiana_,
were laid in two periods: The first from May 15 to 23 occupying
each of the five nests of the fantail warbler available between
these dates, and, then, from June 1 to 18 in all the nests then
available in that particular area. Finally a series of eggs of one
cuckoo that were taken from 1925 to 1935 consisted of the following
numbers: 6, 8, 14, 9, 10, 12, 15, 18, 14, 11, 15. In 1925 and 1926
woodcutters were working in the pinewoods surrounding the open
patch in which the fantail warblers were breeding and doubtless
drove these little birds away and so deprived the cuckoo of foster
parents during the latter period of her laying, or probably larger
series would have been obtained in that particular patch of
grassland. The various series prove satisfactorily that eggs are
normally deposited every alternate day and, also, that there is no
interval in the laying period dividing it into two.
The weights of 1,368 eggs of the Khasia Hills cuckoo are as
follows: Average weight 231; maximum 307; minimum 153 milligrams;
this latter is, however, an abnormally small light egg and very few
will be found less than 180 milligrams.
The same number of eggs measure: Average 23.76 by 17.43; maxima,
28.5 by 18.0 and 27.1 by 20.0; minima 20.9 by 16.3 and 23.4 by 15.0
millimeters.
I should, perhaps, not omit to say that though the generally
accepted idea that cuckoos’ eggs can be distinguished by their
weight is in most cases correct, it is not always so. For instance,
I have 37 eggs of this cuckoo taken in shrikes’ nests, and a
comparison of weights and measures of the eggs of the two species
is as follows:
_C. c. bakeri, 37 eggs_ _Lanius n. nigriceps, 100 eggs_
Average size: 23.56 by 17.50 mm. 23.60 by 17.9 mm.
Average weight: 232 mg. 215 mg.
Maximum weight: 266 mg. 249 mg.
Minimum weight: 190 mg. 185 mg.
The comparative weight of the eggs of different species of birds
varies greatly. Thus _Anthus_ eggs are normally very light while
the eggs of _Passer_ are very heavy, two of the former about
equaling three of the latter of the same size and, in a few cases,
otherwise indistinguishable in coloring, shape, etc. Hoopoes’ and
spine-tailed swifts’ eggs are very heavy, far more so in comparison
with their size than those of cuckoos.
This shows that weight alone in some cases does not suffice to
distinguish cuckoos’ eggs from their fosterers’ eggs, and other
comparisons of cuckoos’ eggs with those of other species could be
quoted to confirm this. The hard _gritty_ shell with fine pits at
wide intervals is a further good distinguishing feature of cuckoos’
eggs, while when blowing it is noticeable that most cuckoos’ eggs
have the yolks tinged with flesh color and very pale, while the
white is rather more opaque, like the white of a duck’s egg when
compared with that of a fowl.
In Europe it is very rare to find two eggs of cuckoos in a nest
laid by the same female; in India this is not so rare, and I have
on three occasions found three eggs of the same cuckoo in one nest.
It is not possible here to go fully into the fascinating subject of
the method of deposition of eggs, but briefly it may be said that
it has been fully proved that in many cases cuckoos lay their eggs
directly into open nests, an act that has been witnessed by myself,
Whitehead, and others in India and proved by Chance (1922) to be
the case in England.
There are, however, any number of eggs deposited by cuckoos in
nests into which it is utterly impossible for the cuckoo to gain
an entrance. Into many of these the cuckoo projects her egg from
the cloaca by pressing herself up against the entrance to the nest
and ejecting her egg with sufficient force to propel it the 2 or
3 inches that may be necessary for it to reach the nest (Livesey,
1936; A. E. Jones, 1937).
On the other hand, there are many nests to which this method also
would not apply, such as nests of small birds, more than 2 or 3
inches inside holes of various character, in some cases a corner
having to be turned before the nest is reached. Into these I
believe the cuckoo places her egg with her bill, and there is some
evidence to support this which I hope to give in my proposed book
on “Cuckoo Problems.”
_Young._--Incubation, I think, takes usually 12 or 13 days, rarely
only 11 days but occasionally extending to 14. The period the
nestling remains in the nest is 4 to 6 weeks, but in many cases the
nest is far too small to retain the young cuckoo until it is full
grown. Thus when the eggs are deposited in the nests of birds such
as _Cisticola_ and, to a lesser degree, _Suya_, the young bird when
a quarter grown fills the small egg-shaped nest, sitting in it with
its head projecting from the entrance at the top side. Gradually,
as the young cuckoo grows, the nest is expanded until it looks
like basketwork around it, which finally bursts, depositing him or
her on the ground. This generally occurs when the cuckoo has fair
feathering and is about half grown or a little later.
The young Khasia Hills cuckoo ejects the fosterer’s eggs or
young from the nest in the same way as its English cousin does,
possessing the same curious interscapulary pit to assist it in
doing so. This structural aid to ejection is found in all such
genera as _Cuculus_, _Cacomantis_, _Penthoceryx_, and others that
eject their foster brothers and sisters, but not in the young of
_Clamator_, _Eudynamis_, and those cuckoos that do not commit such
murders. In the cuckoos that possess it, the pit soon fills in and
young cuckoos lose the impulse to eject after a very short time,
sometimes within 4 days and almost invariably within a week of
being hatched.
_Plumages._--Male: Whole upper plumage and wing coverts a dark
slaty-gray or blackish slate, decidedly darker than the same
parts in the European cuckoo; the lower back, rump, and upper
tail coverts are a purer and somewhat lighter gray; the wing
quills and concealed portions of greater coverts more brown, the
quills slightly glossed and barred with white on the inner webs
of the outer primaries, turning to rufous on the inner primaries;
tail ashy black tipped with white and with white notches along
the sides of the shafts, the white increasing in extent on the
lateral tail feathers; chin, throat, sides of head and neck, and
the upper breast ashy gray, not so dark as the back; remainder of
lower parts, axillaries, and under wing coverts white with rather
irregular bands of black, broader and farther apart than in _C. c.
canorus_. Under tail coverts the same but with the dark bars still
farther apart.
Female: Differs in having a rufous tinge on the upper breast and
sometimes on the throat and sides of the neck.
Nestling: Naked when hatched.
Juvenile: First plumage; whole plumage brownish gray or slate,
obsoletely barred with buffish white; a patch of white on the nape
or hind neck; whole lower plumage barred white or rufescent white
and dark brown, very heavily on the chin, throat, and breast, and
less so on the under tail coverts.
The young male after the first molt is like the adult but nearly
always retains traces of the juvenile barring, more especially so
on the wings.
Hepatic females have the whole upper parts barred chestnut and
blackish slate or blackish brown; the lower plumage has the chin,
throat, and breast barred pale chestnut and blackish and generally
with a strong rufous tinge on the breast and abdomen.
Young hepatic females are duller in color than the adults and have
the feathers of the upper part fringed with white.
_Colors of soft parts._--Iris pale to deep yellow, sometimes
brownish in young birds of the year; bill dark horny brown, or
very dark horny green, paler and yellowish at the base and on the
commissure and orange-yellow on the gape; legs and feet wax-yellow.
_Measurements._--Wing 220 to 227; tail 155 to 178; tarsus 18
(La Touche) to 19; culmen from feathers of forehead 20 to 22
millimeters (24 La Touche).
_Food._--The principal food of this, as of other cuckoos, consists
of caterpillars, pupae, chrysalides, and soft insects of any kind.
During flights of termites cuckoos may be seen both catching them
on the wing and eating them on the ground as they emerge from it. I
have also taken Cicadae from their stomachs, and occasionally quite
hard beetles of considerable size.
The actions of this bird when attempting, and indeed succeeding in,
the catching of termites in flight are very clumsy and labored and
their progress on the ground very slow, similar to the progress of
certain woodpeckers when hunting a lawn for ants and other prey.
As a rule they feed in trees at some height from the ground, but
any plague of caterpillars will tempt them down to quite low
undergrowth or even onto low grass in the open, and I once saw four
cuckoos all feeding on small green caterpillars on the ground in an
open glade in pine forest.
_Behavior._--Normally cuckoos are seldom found on any but high
trees, often resting in one position for a long time on some lofty
branch and then flying to another tree with strong, easy beats
of the wing, at a considerable speed. In the breeding season the
females undoubtedly mark down the nests in which they intend
to deposit their eggs, and they may be seen perched in a tree,
watching their victims until these latter give away the position
of the nest. While thus engaged the patience of the cuckoo seems
inexhaustible, and it will sit for hours in one position, hardly
moving, yet obviously watching the intended fosterers, which may
be loath to return to their nests though they may come and perch
on the same tree as that occupied by the cuckoo, sometimes within
a few feet of her. Apparently they not only mark down nests for
immediate victimization, but others to be made use of when later
eggs are to be laid. At other times they seem to be able to
ascertain the approximate, yet not the exact, position of a nest.
(Livesey MS.) gives me a most interesting example of this. He
writes:
“Yesterday, May 19, 1937, I was out for a walk with my wife about
5 p. m. at Taungyi, which has an elevation of some 5,000 feet.
Close to my cottage the dogs chased a bird off a ploughed field,
which I recognized as a cuckoo. The cuckoo returned with two chats
after her and perched on some bamboo rails, so, suspecting that
the chats had a nest somewhere near in which the cuckoo was going
to lay, I sat down to wait and watch with my glasses. Back came
the cuckoo and flew low over the field almost settling on a place
some 50 yards in front of us. Twice she flew backward and forward,
chased by the chats, finally settling where I expected the nest
to be. I could see her very plainly through the glasses as with
throat feathers puffed out and crest feathers sometimes raised she
jumped clumsily from clod to clod searching for the nest, straining
her neck up and looking everywhere. The chats were now mobbing her
furiously and in retaliation she only opened her beak and made
faces at them. She did not appear to know where the nest was and
began a systematic search for it in an area about 5 by 3 yards.
The clods in the field were very large and lumpy with all sorts
of holes which might have held a nest, and from time to time she
disappeared from sight as she hopped into the various depressions,
going backward and forward in the most persistent manner, mobbed
all the time by the chats.
“She was, I think, a full 10 minutes searching for the nest,
but, at last she dipped out of sight and a flutter of her wings
suggested she had found the nest and was in the act of laying. She
was out of my sight for about 4 seconds and then sped away in a
great hurry.
“We climbed the fence and walking up to the place whence she had
flown found a very well-concealed chats’ nest in which by stooping
down to the ground I could see that the nest contained two eggs,
the cuckoo’s and one of the chat’s; by using the tips of my two
fingers I was just able to draw the eggs out, one at a time with
considerable difficulty.”
_Voice._--The call of the male during the breeding season is
exactly the same as that of the European cuckoo, but in winter
it also has a single note sounding like _chuck_ softly repeated
two or three times. At the beginning of the season the bisyllabic
note, from which the bird derives its name, is not perfect and the
imperfections cover quite a wide range of variations. Sometimes the
note is single instead of double; often it is preceded by a rather
hoarse note of the same character as the call, while sometimes
the _cuck-oo_ is followed by another hoarser note. The female has
the summer bubbling note of its cousin and also certain chuckling
notes, very seldom uttered, while in winter it gives vent to the
same soft _chucks_ as the male. Whether the female ever calls
_cuckoo_ is disputed, but, personally, I am fairly certain that
she does, although it may be but seldom. The bubbling note is the
call to the male and is also repeated after she has met her mate,
but it is then, I think, lower and softer, perhaps an expression of
satisfaction.
During the daytime the calling of the male is almost continuous,
but that of the female far less so as the former calls in the
presence of a female, while the latter does not “bubble” before the
male except at the moment she takes to flight and invites him to
follow her.
On moonlight nights the male often calls with as much persistency
as during the day, but I have never heard it calling on dark nights
until dawn is advanced.
_Enemies._--Cuckoos have the usual enemies of all bird life, vermin
of every kind, which during the breeding season hunt for and devour
all the eggs and young they can find. All the civet-cat tribe,
snakes, lizards, and iguanas are inveterate thieves of eggs and
young, while even more destructive than these are the birds of the
crow and magpie tribe, which systematically hunt out the nests and
devour their contents. I have often watched the birds of the genus
_Dendrocitta_ and _Cissa_ beating over an area in search of nests,
quartering it with the care and energy of a spaniel after game. The
young birds suffer also very greatly from being too large for the
nests in which they are hatched. Half grown they fall out on to the
ground, and many, which escape death from vermin, are killed by
exposure to heavy rain.
The older birds seem to have no special enemies, their swift flight
and comparatively large size saving them from the sudden death so
often the fate of smaller, slower birds. At the same time birds
of prey undoubtedly attack and kill them just as they would any
other bird of similar size and their superficial resemblance--in
human eyes--to a sparrow hawk, would certainly not deceive their
would-be destroyers even if these were sparrow hawks. Nor do the
small birds attack cuckoos because they _believe_ them to be hawks,
but because they _know_ them to be cuckoos and, in their own way as
objectionable as hawks.
_Fall._--The Khasia Hills cuckoo is far more sedentary in character
than its nearest relations and, possibly, is originally a sedentary
race from which the migratory forms have sprung. I have seen the
bird in the Khasia Hills in every month of the year except February
and, as it is silent in the winter months and does not call
attention to its presence, it is probably even more numerous in its
breeding range at this time than has hitherto been supposed, while
some individuals may be resident in the same locality all the year
round. At the same time migration does take place in some degree
and this dark race has been found in winter, certainly, in Bengal,
more especially in the eastern districts on the Bay, in Orissa,
once by Annandale (MS.), while it extends through Burma, south to
Prome (Mackenzie and Hopwood, MS.); south Siam (E. G. Herbert, MS.)
and finally, almost certainly, to southwestern China. I have no
proof that in the Indian Empire adult cuckoos migrate any earlier
than the birds of the year. About September the pleasant call,
which has been heard continually up to the end of July and casually
up to the end of August, ceases entirely, and the birds are also
far less frequently seen on the higher ranges of hills and, by
October, nearly all the birds, old and young, have left these and
have taken to the lower hills and the broken country at their
bases, thence slowly and gradually extending into the plains in the
districts already mentioned. It is also possible, of course, that
this cuckoo may range farther south in winter than stated above, as
records of _Cuculus canorus_ (subspecies?) have been recorded from
Madras and from the islands of the Austro-Malayan region, between
October and March, some of which almost certainly refer to this
form. At present, from the evidence at my disposal, I can neither
substantiate nor refute this suggestion, as it is quite impossible
to recognize one subspecies from another in the field unless a
particularly bright light shows up the comparative slaty darkness
of this bird, to an observer with some experience of cuckoos.
DISTRIBUTION
Exact details as to the distribution of the Khasia Hills cuckoo
are still wanting as so many records of cuckoos refer merely to
the species, _Cuculus canorus_, while the subspecies is not given
or, indeed, in many cases distinguished. The breeding area has
been _proved_ to extend throughout the hills of Assam and Burma as
far south as Karen-nee and as far east as Yunnan, while Bangs and
Peters (1928) consider it is this form that is found and breeds
in eastern Tibet and Szechwan. To the west the breeding cuckoo in
the Bhutan Hills is undoubtedly of this race, but how much farther
west it may extend is not known though, almost certainly, it may be
found breeding in the lower Himalayas below Sikkim. Stevens informs
me that he believes it does.
A fine series of breeding specimens in the Stevens collection,
collected by him in the Sikkim Hills, indicates that the range of
_bakeri_ is below 7,000 or 8,000 feet, and that above that, up to
12,000 feet, _telephonus_ is the breeding form.
In the cold weather it extends to the countries mentioned above in
this article as being visited on migration. To these may be added
that it occurs in Siam, as far south as Bangkok and the Siamese
peninsula west of Tenasserim. Finally, extraordinary as it may
seem, it has been recorded by Friedmann (Friedmann and Riley, 1931)
as having once been obtained in St. Lawrence Island, Bering Sea, an
occurrence that entitles it to a place in the American avifauna.
This specimen was originally described as belonging to the central
and northeastern Asiatic race _telephonus_, which one might expect
would occur at long intervals in Alaska.
Order TROGONIFORMES
Family TROGONIDAE: Trogons
TROGON AMBIGUUS AMBIGUUS Gould
COPPERY-TAILED TROGON
HABITS
This gorgeous Mexican species brings color from the Tropics, all
too rarely, across our borders in extreme southern Texas and
southern Arizona. Ever since Lieutenant Benson shot an immature
male in the Huachuca Mountains on August 24, 1885, it has been
known to occur there and in other neighboring localities in Arizona
as one of our rarest birds. Specimens have been taken there under
circumstances that would indicate that sometime its nest will be
found within our borders. An adult female was shot by F. H. Fowler
(1903) in the Huachucas during August 1892. Major Bendire (1895)
writes: “Another adult female, which evidently had a nest close
by, was obtained by Dr. Edgar A. Mearns, United States Army, on
June 23, 1892, on the east side of the San Luis Mountains, close to
the Mexican boundary line. The long tail feathers in this specimen
are much worn and abraded, and look as if the bird had passed
considerable time in very limited quarters. Its mate was also seen,
but not secured. Judging from the character of the country this
species inhabits in southern Arizona, that is pine forest regions,
it is probably only a straggler, in the lower Rio Grande Valley in
Texas, and does not breed there.”