LEARNING ABOUT
HUMMINGBIRDS
Hummingbirds are a joy for a
birdwatcher to observe. They are found
only in the Western Hemisphere, from as
far north as Southeastern Alaska and the
Maritimes of Canada and as far south as
Southern Chile. There are approximately
350 species of hummingbirds with 320
species found in the tropics. Within the
family of hummingbirds is found the
smallest bird in the world, the Bee
Hummingbird of Cuba at 2.17 inches (5.5
cm) and weight 1.95gm (0.07 oz).
Hummingbirds range in size from 2 inches
to 8 inches.
The hummingbird derives its name from
the humming sound that is produced by its
rapid wingbeat. Generally the wingbeat is
so rapid that the individual only sees a
blur as most of these birds flap their
wings about 50 times per second. The
speed of the wingbeat depends on the size
of the bird, the largest the Giant
Hummingbird, has a wingbeat rate of 10-15
times per second. The fastest recorded
rate was about 80 times per second, on a
tiny Amethyst Woodstar, and the slightly
smaller Bee Hummingbird - the world's
smallest bird - may have an even faster
rate. A hummingbird's wing is flexible at
the shoulder, but inflexible at the
wrist, this enables them to fly in many
different directions. They can fly right,
left, up, down, backwards and even upside
down. To move away from the flowers on
which they feed hummingbirds fly
backwards and are the only bird able to
fly backwards. While other birds get
their flight power from the downstroke
only, hummingbirds also have strength on
the up-stroke. Though they fly very fast,
they can suddenly stop and make a soft
landing. They are so light they do not
build up much momentum. Hummingbirds have
poorly developed feet, so that although
they are able to perch and will do so
when feeding or resting, they do not
walk. In order to move, even along a
branch, they fly. Hummingbirds lift from
perches without pushing off; they rise
entirely on their own power, flapping
their wings at almost full speed before
lifting off. Hummingbirds sleep perched
on branches with their neck retracted and
their head forward, the bill pointed up
at a sharp angle, and the feathers
fluffed.
It is believed that hummingbirds live
for only 3 to 4 years. They have a fast
heartbeat with a rate of 1260 beats per
minute having been measured in a
Blue-throated Hummingbird. In torpid
hummingbirds, the heart rate can drop to
50-180 per minute. Their fast heart rate
and rapid wing motion require them to
feed regularly throughout the day. It is
reported that they must feed every 10
minutes and they may consume 2/3 of their
body weight in a single day. A major part
of a hummingbird's diet is the nectar
they obtain from flowers and their bills
are perfectly adapted to the various
types of flowers that they feed on. Some
hummingbirds have especially curved or
elongated bills that allow them to feed
on special flowers, eg the White-tipped
Sicklebill hummingbird whose downward
curving bill allows it to draw nectar
from heliconias. The Ruby-Topaz
Hummingbird has a short and slightly
decurved bill that is suited to feeding
on the flowers of the ixora shrub. The
Blue-tailed Emerald has a short bill that
is suited for feeding on the Hibiscus
flower. the Copper-rumped Hummingbird has
a straight long bill that allows it to
feed on medium sized tube shaped flowers
such as the allamanda. In feeding,
hummingbirds use their tongue to lap the
nectar in a similar manner to cats
lapping milk. Their tongue can extend a
distance equal to their beak length. As
they feed hummingbirds accidentally
collect pollen and as they move from
flower to flower, they help the flowers
to reproduce.
Hummingbirds have little or no sense
of smell, so colour is important to a
hummingbird's search process for locating
flowers containing nectar. While they
will visit any flower that has sufficient
nectar they prefer flowers that are red
to orange in colour. It is believed that
there are several reasons for this colour
preference. Red flowers standout in a
green background and so are more easily
seen by the hummingbird. It is also
believed that because hummingbirds
compete with insects for nectar they
choose flowers that are less likely to be
visited by insects. Most insects do not
see well at the red end of the colour
spectrum and so may not visit red flowers
while hummingbirds see the full visible
spectrum.
Hummingbirds also need protein in
order to build muscles, so they eat
insects. They prefer to feed on small
spiders and slow-flying insects such as
gnats, small wasps and leafhoppers, which
are rather buoyant in air and easy to
catch. They also probe the bark and
foliage for insects such as aphids,
spiders, caterpillars and insect eggs. It
is believed that up to one-half of their
diet is made up of small insects.
Hummingbirds are capable of living for
extended periods without nectar as a
component of their diet. They can quickly
convert fat reserves and recently
ingested insects to energy when deprived
of nectar. Hummingbirds compete for
nectar and insects and so they develop
territories, which they guard
aggressively. They will fight with other
hummingbirds that enter their territory
but serious harm is seldom inflicted
during these fights. Also when food
sources are scarce they fight to protect
their source.
Most hummingbirds are green except
hermits, which are mainly brown, and are
known for the iridescence. These
brilliant, iridescent colors of the
hummingbird plumage are caused by the
refraction of incident light by the
structures of certain feathers. These
structures split light into its component
colors, and only certain frequencies are
refracted back to the viewer. The brown
colour in some hummingbirds is the result
however of pigmentation. Hummingbirds
groom themselves with their bills and
claws, using oil from a gland near their
tail. They also use their claws like a
comb to groom their heads and necks. They
sunbathe positioning their breast towards
the sun and fluffing out, extending their
neck and spreading their tail.
Hummingbirds also take water baths using
the water in shallow pools or cupped
leaves. They flutter their wings or pull
them straight back while lifting and
spreading their tail; they dip their
chins and bellies into the water. At
times they can be seen sitting on a bare
branch allowing the rain to soak through
to their skin. After bathing they will
preen and dry their feathers.
Hummingbirds build cup shaped nests,
however hermits build long hanging nests
usually attached to foliage. Male
hummingbirds do not contribute to the
building of nests or the care of young.
All feeding is therefore left to the
female. When feeding the female perches
on the side of the nest, arches her back,
stretches her neck, lifts her head, and
holds her bill down to regurgitate nectar
and half-digested insects to her babies.
Her throat swells and she pumps her beak
like a sewing needle.
Although various larger birds, snakes,
and mammals raid hummingbird nests for
eggs and chicks, this is not a major
cause of death.
About The Author
Brian Ramsey is the author of the CD,
Discovering the Birds of Trinidad and
Tabago found at: http://www.birdsoftt.com
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