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Green Heron
Butorides virescens
Contributed by Charles Wendell Townsend
[Published in 1927:
Smithsonian Institution United States National Museum Bulletin
135: 185-194]
Familiarity with the habits of this well-known little heron
explains its common or vulgar names such as
"fly-up-the-creek," "chalk-line," "shite-poke,"
and "skeow." These names are of long standing and very
expressive, for the bird is a familiar one to the country boy and
to the fisherman by stream or pond, where the tameness or
stupidity of this bird often brings it within close range.
Spring.--The migratory flights of
the green heron are generally made at night and are described by
Audubon (1840) with his usual picturesqueness. He says:
I have observed their return in early spring, when arriving
in flocks of from 20 to 50 individuals. They would plunge
downwards from their elevated line of march, cutting various
zigzags, until they would all simultaneously alight on the tops of
the trees or bushes of some swampy place, or on the borders of
miry ponds. These halts took place pretty regularly about an hour
after sunrise. The day was occupied by them, as well as by some
other species especially the blue, the yellow-crowned, and night
herons, all of which at this period traveled eastward, in resting,
cleansing their bodies, and searching for food. When the sun
approached the western horizon, they would at once ascend in the
air, arrange their lines and commence their flight, which I have
no doubt continued all night.
Courtship.--Audubon (1840) says:
During the love season they exhibit many curious gestures,
erecting all the feathers of their neck, swelling their throat,
and uttering a rough guttural note like 'qua, qua,' several times
repeated by the male as he struts before the female.
Mrs. Irene G. Wheelock (1906) describes the dance or
"hornpipe of a solitary green heron" in June,
"although," as she says, "possibly his mate may
have been an unseen witness. Backward and forward, with queer
little hops, he pranced first on one foot and then on the other. .
. . The effect is as ludicrous as though a long legged, dignified
D. D. were to pause in his learned discourse and execute a double
shuffle."
Nesting.--The green heron nests
singly or in colonies. Although it generally prefers for its
nesting locality a region close to the water, it may choose dry
woods or an orchard in the midst of cultivated ground. The height
of the nest is also very variable, and although most nests are
placed from 10 to 20 feet from the ground, they may be found in
the tops of high trees, or, on the other hand, on low bushes or
even on the ground. Hatch (1892) says: "Instances have
occurred under my observation, where in the entire absence of
trees or bushes of any size, they have placed the nest, composed
of coarse dry weeds and reeds and cat-tails, on a tussock in a
reed-hidden quagmire." And he mentions one that was built on
the top of a muskrat house. Maynard (1896) says that in Florida,
"among the keys, they often place their domiciles on the
roots of the mangroves, frequently not over 6 inches above
high-water mark." W. J. Erichsen (1921) in his observations
in Chatham County, Georgia, says:
These birds breed in considerable numbers on Sylvans Island
on the Herb River, some 3 miles from the town of Thunderbolt,
placing their nests in the extreme tops of tall pine saplings.
Probably the most populous colony in the county is near Lazaretto
station on Tybee Island. Here the birds breed in a jungle of oaks
difficult to penetrate. So numerous are they that every available
nesting site is occupied, many new nests being built on the
foundation of old ones.
In Massachusetts, I have generally found single nests, but on
several occasions, small colonies. One at Magnolia, many years ago
between the beach and a fresh water marsh, consisted of 20 or 30
pairs nesting in pitch pines about 20 feet from the ground.
Another colony was on an island in the salt marsh at Ipswich in
trees of gray birch, red oak, and hickory about 15 feet from the
ground. A colony of about 20 nests at Westport on a salt marsh
island was in cedars, sassafras, and hickories. In this case the
nests varied from 3 to 20 feet from the ground.
The nest itself is a simple affair from 10 to 12 inches in
diameter, ill-adapted, it would seem to hold eggs when the tree
branches wave in the wind, for it is a flat platform of sticks,
destitute of any sort of lining and not cup shaped. Some at least
of the twigs composing the nest are green. The nest is so thin and
flimsy that one can sometimes look through it from below and see
the eggs. In making the nest the herons must weave the twigs in
and out to a certain extent, for if they merely laid the sticks
one on top of the other, the nest would fall to pieces at the
least disturbance. The nests on the ground made of course weeds,
reeds, and cat-tails already mentioned are very unusual both in
site and material.
The green heron does not nest with other species as a rule, but
is occasionally found nesting in the same grove with little blue,
Louisiana, black-crowned, and other herons. The boat-tailed
grackle and the bronze grackle have also been found nesting in the
same group of trees. Mrs. Wheelock (1906) says of the association
with the latter birds:
The grackles were quarrelsome, thieving, noisy, and the only
possible advantage the herons could hope to derive from them would
be the loud alarm always given by them at the approach of danger.
Eggs.--[Author's note: Green herons
have been known to lay from three to nine eggs, but the ordinary
sets consist of four or five eggs; the larger sets are probably
the product to two females. The eggs are ovate or oval in shape.
The shell is smooth without gloss and the color varies from
"pale glaucous green" to "pale olivine."
The measurements of 43 eggs average 38 by 29.5 millimeters; the
eggs showing the four extremes measure 41 by 28, 40.5 by 30.5,
36 by 27.5 millimeters.]
Young.--The incubation
according to Burns (1915) is 17 days. The young at an early age
are expert climbers among the branches of the nesting tree, long
before they are able to fly and while the natal down still adheres
to the juvenal feathers and forms a halo around their heads. In
climbing they make use of their feet, wings and bill, or, rather
of the neck, hooking their bills and chins over the branches and
pulling themselves up. The bastard wing is extended during the
climbing process, suggesting an ancestral, reptilian use, but
whatever power it may have had in the past, this was long since
lost. I have never seen any attempt to use the bastard wing in
grasping. If the ornithologist climbs the tree in order to observe
the half-grown young in the nest, these almost always leave in
haste and scatter to the outermost tips of the branches.
Another ancestral trait, which is suggested in the adult by the
persistence of a distinct web between the middle and outer toes,
is an ability on the part of the young to swim, an inheritance
which must be of distinct value in many cases where the young fall
from the nesting tree or bush into the water below. I once placed
a vigorous half-grown young green heron in the water below its
nest and was delighted to see it sit erect like a little swan and
paddle gracefully off, using its feet alternately. It seemed
perfectly at ease, dabbed at the water occasionally with its bill,
swam a creek 20 yards broad, and threaded its way among the grass
stalks until it disappeared from sight. The grace and ease with
which it swam contrasted forcibly with its movements on land. The
adult also is able to swim.
When the young are approached too closely, they regurgitate the
contents of their crops to the discomfort of the seeker after
knowledge, although this action gives the latter an opportunity to
learn the character of their food. Mrs. Irene G. Wheelock (1906),
who has made some interesting and valuable studies of several
families of these birds in southern Wisconsin says:
As soon as the little ones were fairly out of the shells and
before the down was dry on their heads we had taken several
pictures of them. One of these revealed a remarkable heron trait,
for the brand new baby, who had never been fed, and who had
scarcely opened his eyes on this queer world, yet attempted to
protest against our meddling by the characteristic heron method of
defense. In his case the action was merely a nervous
"gagging" and would seem to indicate that this act is
involuntary rather than intentional on the part of all herons. . .
. When first hatched the herons stretched up to a height of 3 1/4
inches, and when 7 days old, 11 inches.
She found that they "gained one-half ounce in weight every
day for 6 days, weighing three-fourths of an ounce at the
beginning and 3 3/4 of an ounce on the seventh day." These
young were fed only in the early morning and in the late
afternoon, and the periods of greatest activity were from 4 to 6
in the morning, and from 5 to 7 in the evening. One record taken
when the young were a week old, showed that they were fed 7 times
in the morning and 7 times in the afternoon. The food was given by
regurgitation but was not predigested.
Plumages.--[Author's note: The
downy young green heron is scantily covered with "drab"
down, thickest on the back and longest on the crown; the color
varies to light gray on the under parts and to "hair
brown" on the crown. The juvenal plumage is acquired in the
usual heron sequence and is complete before the young bird reaches
the flight stage, when fully grown.
The sexes are distinguishable even in the juvenal plumage. In
the young male, in August, the crown is solid, glossy, greenish
black; the sides of the head and neck are solid
"chestnut"; the chin, throat, and neck stripe are
yellowish white, spotted with black; the back is solid, glossy,
dark green; the wing coverts are the same color as the back, but
the lesser coverts are edged with chestnut and the median and
greater coverts are rounded (not pointed, as in the adult), edged
with pale buff and have a triangular buffy white spot at the tip
of each feather; these spots soon fade out to white and then wear
away; the remiges and retrices are glossy, greenish black; the
secondaries and primaries are tipped with white in decreasing
amounts from the inner to the outer; the under parts are buffy
white, streaked with dusky. The young female differs from the
juvenal male in having chestnut streaks in the crown and having
the sides of the head and neck streaked with chestnut, buff, and
dusky.
The juvenal plumage is worn during the fall and early winter,
without much change until the partial prenuptial molt begins in
February; this involves mainly the head, neck, and body plumage,
which, by May, is much like the adult plumage, except that there
is more white in the chin, throat, and under parts, with more
broad, dusky stripes in the fresh plumage of the lower neck and
upper breast than in the adult; some new, fresh back plumes,
scapulars, and wing coverts, similar to those of the adult, are
acquired at this molt; but the flight feathers are old and worn
and some of the juvenal wing coverts are retained. The complete
postnuptial molt begins earlier in young birds than in adults; I
have seen a young bird molting its primaries as early as April
first; at this molt, when the young bird is but little over a year
old, the adult plumage is assumed. The adult wing is easily
recognized by the coverts; the lesser coverts are narrowly edged
with rufous buff and the median and greater coverts are pointed
(not rounded as in the juvenal) and narrowly edged with pale buff;
only the inner primaries and the secondaries are very narrowly
tipped with white.
Adults apparently have a partial prenuptial molt in late winter
and early spring and a complete postnuptial molt from July to
November. I have seen an adult male molting its primaries as late
as January 16, which suggests the possibility of a complete
prenuptial molt, but this may be only a case of delayed molt.
There is very little seasonal difference in adult plumages.]
Food.--The food of the green heron
varies somewhat with the locality. In birds taken in salt marshes,
I have found the stomach contents to consist of the minnows common
in the little creeks together with a variable amount of sand. Live
stomach worms are also common, a fact mentioned by other
observers. In regions of fresh water, tadpoles, water insects and
their larvae, crayfish, and small bony fishes are common articles
of diet. Food is also gathered in the uplands by these birds and
their stomachs have been found to contain earth worms, crickets,
grasshoppers, snakes, and small mammals. Grasshoppers in very
large numbers have sometimes been found. B. S. Bowdish (1902) says
the food of the green heron in Porto Rico: "Several stomachs
examined contained respectively, remains of lizards and crabs, and
one whole fish about 6 inches long; a kind of water beetle about
three quarters of an inch long, many entire; crawfish and
grasshoppers; 11 crawfish; small live worms." Oscar E.
Baynard (1912) reports that the stomach of an adult green heron
taken in Florida contained 6 small crayfish, 16 grasshoppers, 2
cut worms and the remains of small frogs.
Behavior.--William Brewster
(1906) said of the green heron:
Like the crow and black duck, it is at once a wary and
venturesome bird, endowed with sufficient intelligence to
discriminate between real and imaginary dangers and often making
itself quite at home in noisy, thickly settled neighborhoods where
food is abundant and where it is not too much molested.
The green heron is equally at home in the salt water marshes
and in the regions of fresh water. It is a day feeder but prefers
the early morning and late afternoon, often taking a nap at
midday. One of the familiar sounds and sights by salt creek or by
river or pond is the frightened cry of this bird and its awkward
flight over the water. The names "skeow" and
"fly-up-the-creek" are expressive of these attributes.
The classic names "chalk-line" and "shite-poke"
express the commonly observed physiological effect of fright. This
effect must incidentally serve a useful purpose in blinding the
stealthily creeping pursuer, be it carnivore or savage.
The length of the neck of the green heron in life is a most
variable one and this bird well deserves to be called "rubber
neck." Early one May morning I watched unseen one of these
birds with its neck drawn in creeping along the branches of a
spruce. In the dim light it looked more like a mammal than a bird.
Suddenly it elongated its neck and seized with its bill a twig of
a near-by elm, but was unable to break it off. It tried another
and another and finally succeeded in tearing the green twig off
from its base. I watched another bird as it awoke from its morning
nap and, as it stretched its neck to an equal length with its body
and shook out its feathers, the general form and appearance of the
bird went through a marvelous change. In short flights this heron
may retain the elongated pose of the neck, but in longer ones it
folds up and retracts that member.
When walking about, especially if it knows it is watched, the
green heron nervously twitches its tail downward and erects and
depresses its crest. It is also able to remain perfectly still,
especially when on the watch for game. A common posture assumed on
the margin of the pond or sand flats at low tide is with the back
and neck horizontal and the tarsi so nearly flat on the ground
that the body is close to the same. The bird under these
circumstances is easily mistaken for a log of wood. In this
position it waits patiently, ready to pounce on the little fish
that swim its way and it rarely misses its aim. At other times it
approaches stealthily, putting down each foot with care and
secures its prey with a quick stroke. That this stroke must be
quick and accurate is evident when we consider the nature of some
of its food, frogs, fish, and grasshoppers.
That green herons in some cases jump or even dive into the
water after their prey, is shown in the following account by
Samuel H. Barker (1901) who saw an individual plunge from a plank
after fish into a pond 3 to 6 feet deep.
Although he missed his aim, the effort was well meant and,
to judge by appearances, not the first of its kind. Turning about
in the water, he rose from it with little difficulty and with a
few flaps was back on the plank. . . . That this one instance of
an individual green heron plunging into deep water after food
proves such to be a natural habit of the species can hardly be
said. I would add, however, that further study of the feeding
habits of the green heron, with a view to settling this question,
convinces me that a quite usual method of fishing is for it to
watch from a stand a few inches above the water and from there to
jump quickly down upon its prey.
W. Sprague Brooks (1923) watched a green heron walking
stealthily along the stone rim of the Public Garden pond in
Boston.
After a while it turned cautiously until facing the water,
toes at the rim of the stone, its neck stretched out full length,
and suddenly, as a swimmer in a race plunges from the marble rim
of a tank, it plunged into the water, completely submerged, came
to the surface with a goldfish which it immediately swallowed, and
raising its wings, flew back, only a matter of two wing strokes,
to the stone border. Twice I watched it do this.
The note commonly emitted by this bird as
it flies from the intruder can, perhaps, best be represented by
the syllables peu-ah. It generally resembles very closely
the sound made by blowing a blade of grass stretched tightly
between the thumbs side by side. When much startled the green
heron croaks hoarsely but soon returns to the usual peu-ah.
Sometimes, especially about the nesting tree, it may be heard to
give a short cackle or cluck. Early one morning, when I was lying
concealed in a grove of trees, a green heron alighted among them
nearly over my head. Thereupon it emitted a series of low double
groans at irregular intervals. If I had not seen the bird, I
should have been puzzled as to the source of the sounds.
The small size of this heron, somewhat
smaller than a crow, its short cut-off tail, its general
greenish-black color with a chestnut-colored throat and
bluish-gray primaries make its recognition in the field easy.
The green heron is too interesting a bird to be used for a pot
hunter's target as is often the case. He who is so fortunate as to
have a breeding place for this bird near him should zealously
guard it and he will learn many interesting and amusing traits and
will be well rewarded.
Green Heron*
Butorides virescens
Contributed by Charles
Wendell Townsend
*Original Source: Bent,
Arthur Cleveland. 1927. Smithsonian Institution United
States National Museum Bulletin 135: 185-194. United States
Government Printing Office
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