BIRDS
– OUR WINGED FRIENDS!
Birds
– our winged friends are important components of our life cycle. They are also
called as “Aves" and "Avifauna". They are a group of endothermic vertebrates, with feathers, a beak with no teeth, laying hard-shelled eggs, with a high metabolic rate, a four-chambered heart
and a
lightweight but strong skeleton. Birds live worldwide and range in
size from 5 cm bee humming bird to the 2.75 m ostrich. More than half of these are passerines, known as perching birds or
as song birds.
Birds are the last surviving dinosaurs according to the fossil records, having evolved
from feathered ancestors. Birds have wings which are more or less
developed depending on the species; wings evolving from forelimbs, giving most birds the ability
to fly.
There are
some flightless birds, including ratites, penguins and diverse endemic island
species.
The digestive and respiratory systems of birds are uniquely adapted
for flight. Some bird species of aquatic environment have evolved for swimming. Birds played an important part in
the inception of
Darwin's theory of evolution by natural selection.
Some birds, especially corvids and parrots, are among the most intelligent animals; several bird species make and use tools, and many social species pass on knowledge across generations, which is considered a form of culture. Many species annually migrate great distances. Birds are social, communicating with visual signals, calls and bird songs, participating in social behaviors like cooperative breeding and hunting, flocking and mobbing of predators. A vast majority of bird species are socially monogamous, either for one breeding season at a time, sometimes for years, but rarely for life. Birds produce offsprings by laying eggs fertilized through sexual reproduction. They are usually laid in a nest and incubated by the parents. Most birds have an extended period of parental care after hatching. Some birds, such as hens, lay eggs even when not fertilized, which do not produce offspring.
Birds occupy a wide range of
ecological positions. While some birds are generalists, others are highly
specialized in their habitat or food requirements. Within a single habitat,
such as a forest, the niches occupied by different species
of birds vary, with some species feeding in the forest canopy, others beneath the canopy, still
others on the forest floor. Forest birds may be insectivores, frugivores,
and nectarivores.
Aquatic birds generally feed by fishing, plant eating, and piracy or kleptoparasitism.
Birds of prey specialize in hunting mammals or other birds, while vultures are specialized scavengers. Avivores are
animals that are specialized at preying on birds.
Many species of birds are
economically important. Domesticated and undomesticated birds (poultry and game) are important sources of eggs, meat and feathers. Song birds, parrots and other species are popular
as pets. Guano (bird excrement) is harvested
for use as a fertilizer. Recreational bird watching is an important part of
the ecotourism industry. Some nectar-feeding
birds are important pollinators, and many frugivores play a key role in seed
dispersal. Plants and pollinating birds often co-evolve and in some cases a flower's
primary pollinator is the only species capable of reaching its nectar.
Birds are often important to island
ecology. Birds have frequently reached islands that mammals have not; on those
islands, birds may fulfill ecological roles typically played by larger animals.
Nesting seabirds may also affect the ecology of
islands and surrounding seas, principally through the concentration of large quantities
of guano, which may enrich the local
soil and the surrounding seas.
A wide variety of avian ecology field
methods,
including counts, nest monitoring, capturing and marking, are used for
researching avian ecology.
Since birds are highly visible and
common animals, humans have had a relationship with them since ages. These
relationships may be mutualistic, like the cooperative
honey-gathering among honey guides and African peoples such as
the Borana. Other times, they may be commensal,
as when species such as the house sparrow have benefited from human
activities. Several bird species have become commercially significant
agricultural pests and some pose an aviation hazard. Human activities can be detrimental,
and have threatened numerous bird species with extinction (hunting, avian lead poisoning, pesticides, roadkill,
and predation by petcats and dogs are common sources of death
for birds). Birds can act as vectors for spreading diseases like psittacosis, salmonellosis, campylobacteriosis, mycobacteriosis (avian tuberculosis), avian influenza (bird flu), giardiasis and cryptosporidiosis over long distances. Some of
these are zoonotic diseases that
can also be transmitted to humans. Domesticated birds raised for meat and eggs,
called poultry, are the largest source of animal
protein eaten by humans. Many species of birds are hunted for meat. Bird
hunting is primarily a recreational activity except in extremely undeveloped
areas.
Other commercially valuable products
from birds include feathers (especially the down of geese and ducks), which are
used as insulation in clothing and bedding, and seabird feces (guano), which is a valuable source of
phosphorus and nitrogen. Birds have been domesticated by humans both as pets
and for practical purposes. Colorful birds, such as parrots and mynas are bred in captivity or kept as pets, a practice
that has led to the illegal trafficking of some endangered species. Falcons and cormorants have long been used for hunting and fishing, respectively. Pigeons were
used as messengers
in olden times. Such
activities are more common either as hobbies, for entertainment and tourism or
for sports such as pigeon racing,
today.
Amateur bird enthusiasts (called
birdwatchers, twitchers or birders) number in the millions.
Many
homeowners erect bird feeders near their homes to attract
various species.
Birds play prominent and diverse
roles in folklore, religion, and popular culture. In religion, birds may serve as
either messengers or priests and leaders for a deity, as chiefs or as attendants. In
several civilizations of ancient Italy and Roman religion, priests watched their activities
to foretell events. They may also serve as religious symbols. Birds have perceived as Mother
Earth or as monsters.
Birds have been featured in culture
and art since prehistoric times, when they were represented in early cave paintings. Birds were later used in religious
or symbolic art and design, such as the magnificent Peacock Throne of the Mughal and Persian emperors. Birds are
important figures in poetry; for example nightingales.
Perceptions of various bird species
often vary across cultures. Owls are associated with bad
luck, witchcraft and death in parts of Africa but
are regarded as wise across much of Europe.
Birds are
depicted in the process of transgressing boundaries between earthly and
underground spiritual realms.
About 120–130 species have become
extinct due to human activity since the 17th century and hundreds more before
then. Human activity threatens about 1,200 bird species with extinction, though
efforts are underway to protect them. Most common example is
of common sparrows which are almost extinct, probably as a result of particular
electronic waves which seem to harm them.
Though human activities have also allowed
the expansion of a few species, such as the barn swallow and European starling, they have caused population
decreases or extinction in many other species. Many
bird populations are declining worldwide, with 1,227 species listed as threatened by Bird Life
International and the IUCNin 2009.
The most commonly cited human threat
to birds is habitat loss. Other threats include overhunting,
accidental mortality due to structural collisions or long-line fishing by catch, pollution (including oil spills and pesticide use), competition and predation from
nonnative invasive species and climate change.
Governments and conservation groups work to protect birds, either
by passing laws that preserve and restore bird habitat or by
establishing captive populations for reintroductions. Such
projects have produced some successes; one study estimated that conservation
efforts saved 16 species of bird that would otherwise have gone extinct between
1994 and 2004. We all must protect, feed and preserve birds in whatever way we
can, as they are an important part of our life cycle, which may get disturbed
by their extinction.
WORLD SPARROW DAY - 20TH MARCH 2019
PROVIDE THEM WATER AND GRAINS IN A CONSERVATIVE
MANNER!!!
MORE THAN ANYTHING, CONSIDER THEM AS YOUR FAMILY MEMBERS AND LET THEM LIVE AND FLOURISH!
Dr Mrs Jaya Vikas Kurhekar
Green Blogger