The Boat-tailed Grackle was once considered the same species
as the Great-tailed Grackle, though its body size is larger, it has a longer
tail and lacks the Great-tailed Grackles’ distinctly flat head-shape; this
bird’s head is round. This is a medium
sized grackle; at just a couple inches longer than the Common Grackle.
A large, long-tailed blackbird, the Boat-tailed Grackle
is
found exclusively along the Gulf and Atlantic coasts
of
the United States.
The noisy, iridescent, purple-black male has a bluish sheen visible on the head,
in good light, and grading to greenish on the body. The extroverted bird is hard
to miss when it displays on power lines and telephone poles.
Young males are black but lack the adult's
iridescence.
The smaller, brown female
has a shorter tail and reddish brown plumage overall, darkest on wings and
tail. She is quite beautiful but is much less conspicuous and might even be
mistaken for a different species.
Young females
resemble pale adult females, with spots on the breast.
|
Boat-tailed Grackle, eating shrimp. |
General Description:
- Iridescent black body, usually more
blue-green
- Larger, longer tail; held in deep ‘V’ during
display flights
- Very large, long bill
- Yellow to brown eye color, depending on
range/subspecies
Measurements: Both Sexes
Length
10.2–14.6 in
26–37 cm
Wingspan
15.4–19.7 in
39–50 cm
Weight
3.3–8.4 oz
93–239 g
A US native and endemic only here, this grackle is resident
along Atlantic coast from Long Island and New Jersey south, throughout
peninsular Florida, and west along Gulf coast to southeastern Texas. Boat-tailed Grackles have established
significant populations in several United States
Gulf Coast
cities and towns where they can be found foraging in trash bins, dumpsters and
parking lots.
Courtship: The courtship antics of this race are similar to
those described for the eastern form (see p. 366). A great variety of locations
may be used by the displaying or singing bird; E. A. Mellienny, (1937), writing
about the bird in Louisiana, gives a clear picture of such proceedings as
follows:
Their favorite station for plumage exhibition is the top of a small bush or low
tree. If these are not available, they will alight on the ground or on a
muskrat house or pile of debris. Here they stay quietly for some minutes, with
their feathers compressed and beak and neck pointing skyward, then suddenly one
of them will give a series of squeaking, chuckling, raucous cries, during which
all the feathers are fluffed, tail spread, wings half opened and vibrated
rapidly, making a loud, rattling sound [see Voice]. The others of the group
immediately follow the leader's example, and for a minute or two each
individual is animated and noisy, only to drop back to the compressed statue
like pose. This noisy exhibition takes place either while at rest or on the
wing.
If, over such a group of males, flies a female seeking a mate, all of the males
at once take flight on loudly flapping wings and with rattling quills,
squeaking and calling in their most seductive manner, begin chasing her. Should
none of this group of males attract her, she quickly out flies them and
proceeds to look over other groups until she finds her choice. When a mate is
selected she flies in front of and near him, leading him off to one side, until
the other males in the group drop out of the chase. The pair then alights on
the ground and mating is accomplished.
These Grackles generally nest near or over water, in
willows, cattails, saw grass, bulrushes or up to 80’ high in trees. The nest is a well-concealed cup in trees or
shrubs; where three to five eggs are laid.
Boat-tailed Grackle eats various invertebrates, grain, some
small vertebrates; forages on ground, mudflats, and in shallow water. They are omnivorous, eating insects, minnows, frogs, eggs, berries, seeds and grain, even small birds. Larger injured birds are taken by the Boat-tailed Grackle when opportunity offers; sandpipers, heron,egret and more. They will steal food from other birds…or from pet-food bowls.
During the spring and summer the food consists largely of a wide range of
aquatic life: fish, frogs, insects, crustacea, and spiders. The boat-tail's
ability as a fisherman is considerable, and it is often to be seen wading in
pools or marshy creeks, up to its belly, making accurate stabs of the beak at
minnows of various sorts. In some of these maneuvers it immerses the entire
head, in others it hovers like a petrel. The boat-tail seems very fond of the
crayfish, and often searches this creature out on its own; but, as related
under "Behavior," it sometimes seizes them from other birds, notably
the eastern glossy ibis and probably some of the herons. The bird is quite good
as a flycatcher, and secures various insects on the wing with apparent ease
This bird's song is a harsh jeeb, and it has a variety of typically
grackle-like chatters and squeaks, and the characteristic rolling or rattling
sound; often accompanied by a wing-flutter, as shown here.
Cool Facts
- Eye color in the Boat-tailed
Grackle varies from region to region. Grackles along the Atlantic coast
north of Florida have
straw-colored eyes. Florida
birds have dark eyes. Grackles west of Florida
to eastern Louisiana have
light eyes, but those further west have dark ones.
- Fledglings that fall into the
water can swim well for short distances, using their wings as paddles.
- The Boat-tailed Grackle has
an odd mating system: harem polygyny or female
defense polygyny. Females cluster their nests, and the males compete
to defend the entire colony and mate there. The most dominant male gets
most of the copulations in a system similar to that used by many deer. But
all is not as simple as it seems. Although the dominant male may get up to
87% of the copulations at a colony, DNA
fingerprinting shows that he actually sires only about 25% of the young in
the colony. Most of the young are fathered by non-colony males away from
the colonies.
Sources:
·
Wikipedia
·
Cornell’s All About Birds
· Birds by Bent
·
The Crossley Guide – Eastern Birds
·
Kaufman Focus Guide – Birds of North
America
·
Smithsonian Field Guide to Birds of North
America
·
Stokes Field Guide to Birds of North
America
Photos:
·
Wikipedia
·
YouTube