Bird conservation - AbsoluteAstronomy.com

Bird conservation is a field in the science of conservation biology

Conservation biology

Conservation biology is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction...

related to threatened

Threatened species

Threatened species are any speciesg animals, plants, fungi, etc.) which are vulnerable to endangerment in the near future.The World Conservation Union is the foremost authority on threatened species, and treats threatened species not as a single category, but as a group of three categories,...

bird

Bird

Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s. Humans have had a profound effect on many bird species. Over one hundred species have gone extinct in historical times, although the most dramatic human-caused extinctions occurred in the Pacific Ocean

Pacific Ocean

The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

as humans colonised the islands of Melanesia

Melanesia

Melanesia is a subregion of Oceania extending from the western end of the Pacific Ocean to the Arafura Sea, and eastward to Fiji. The region comprises most of the islands immediately north and northeast of Australia...

, Polynesia

Polynesia

Polynesia is a subregion of Oceania, made up of over 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are termed Polynesians and they share many similar traits including language, culture and beliefs...

and Micronesia

Micronesia

Micronesia is a subregion of Oceania, comprising thousands of small islands in the western Pacific Ocean. It is distinct from Melanesia to the south, and Polynesia to the east. The Philippines lie to the west, and Indonesia to the southwest....

, during which an estimated 750-1800 species of bird went extinct. According to Worldwatch Institute, many bird populations are currently declining worldwide, with 1,200 species facing extinction in the next century. The biggest cited reason surrounds habitat

Habitat (ecology)

A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...

loss. Other threats include overhunting, accidental mortality due to structural collisions

Bird strike

A bird strike—sometimes called birdstrike, avian ingestion , bird hit, or BASH —is a collision between an airborne animal and a man-made vehicle, especially aircraft...

, long-line fishing

Long-line fishing

Longline fishing is a commercial fishing technique. It uses a long line, called the main line, with baited hooks attached at intervals by means of branch lines called "snoods". A snood is a short length of line, attached to the main line using a clip or swivel, with the hook at the other end....

bycatch

Bycatch

The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...

, pollution, competition and predation by nonnative invasive species

Invasive species

"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....

, oil spill

Oil spill

An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is mostly used to describe marine oil spills, where oil is released into the ocean or coastal waters...

s and pesticide

Pesticide

Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...

use and climate change

Climate change

Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. It may be a change in average weather conditions or the distribution of events around that average...

. Governments, along with numerous conservation charities

Charitable organization

A charitable organization is a type of non-profit organization . It differs from other types of NPOs in that it centers on philanthropic goals A charitable organization is a type of non-profit organization (NPO). It differs from other types of NPOs in that it centers on philanthropic goals A...

, work to protect birds in various ways, including legislation, preserving

In-situ conservation

In-situ conservation is on-site conservation or the conservation of genetic resources in natural populations of plant or animal species, such as forest genetic resources in natural populations of tree species...

and restoring bird habitat, and establishing captive populations

Ex-situ conservation

Ex-situ conservation means literally, "off-site conservation". It is the process of protecting an endangered species of plant or animal outside of its natural habitat; for example, by removing part of the population from a threatened habitat and placing it in a new location, which may be a wild...

for reintroductions.

See Late Quaternary prehistoric birds

Late Quaternary prehistoric birds

Prehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...

for birds which disappeared in prehistoric and early historic times, usually due to human activity (i.e., starting with the Upper Paleolithic Revolution). For birds having gone extinct in modern times (since 1500), see Extinct birds

Extinct birds

Since 1500, over 190 species of birds have become extinct, and this rate of extinction seems to be increasing. The situation is exemplified by Hawaii, where 30% of all known recently extinct bird taxa originally lived...

Habitat loss

The most critical threat facing threatened birds is the destruction

Habitat destruction

Habitat destruction is the process in which natural habitat is rendered functionally unable to support the species present. In this process, the organisms that previously used the site are displaced or destroyed, reducing biodiversity. Habitat destruction by human activity mainly for the purpose of...

and fragmentation

Habitat fragmentation

Habitat fragmentation as the name implies, describes the emergence of discontinuities in an organism's preferred environment , causing population fragmentation...

of habitat. The loss of forests, plains and other natural systems into agriculture, mines, and urban developments, the draining of swamp

Swamp

A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...

s and other wetland

Wetland

A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

s, and logging

Logging

Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks.In forestry, the term logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard...

reduce potential habitat for many species. In addition the remaining patches of habitat are often too small or fragmented by the construction of roads or other such barriers that cause populations in these fragmented islands to become vulnerable to localised extinction. In addition many forest species show limited abilities to disperse and occupy new forest fragments (see Island biogeography

Island biogeography

Island biogeography is a field within biogeography that attempts to establish and explain the factors that affect the species richness of natural communities. The theory was developed to explain species richness of actual islands...

). The loss of tropical rainforest

Tropical rainforest

A tropical rainforest is an ecosystem type that occurs roughly within the latitudes 28 degrees north or south of the equator . This ecosystem experiences high average temperatures and a significant amount of rainfall...

is the most pressing problem, as these forests hold the highest number of species yet are being destroyed quickly. Habitat loss has been implicated in a number of extinctions, including the Ivory-billed Woodpecker

Ivory-billed Woodpecker

The Ivory-billed Woodpecker is or was one of the largest woodpeckers in the world, at roughly 20 inches in length and 30 inches in wingspan. It was native to the virgin forests of the southeastern United States...

(disputed because of "rediscovery"), Bachman's Warbler

Bachman's Warbler

The Bachman's Warbler, Vermivora bachmanii, is a small passerine bird that inhabits the swamps and lowland forests of the southeast United States. This warbler is a migrant, wintering in Cuba. The Bachman’s Warbler is small for a warbler and is unique for its thin and decurved bill. It has strong...

and the Dusky Seaside Sparrow

Dusky Seaside Sparrow

The Dusky Seaside Sparrow, Ammodramus maritimus nigrescens, was a non-migratory subspecies of the Seaside Sparrow, found in Southern Florida in the natural salt marshes of Merritt Island and along the St. Johns River...

Introduced species

Historically the threat posed by introduced species

Introduced species

An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...

has probably caused the most extinctions of birds, particularly on islands. Ninety percent of historical extinctions have occurred on islands, and most prehistoric human caused extinctions were insular as well. Many island species evolved

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

in the absence of predators and consequently lost many anti-predator behaviours

Island tameness

Island tameness is the tendency of many populations and species of animals living on isolated islands to lose their wariness of potential predators, particularly of large animals. The term is partly synonymous with ecological naïvete, which also has a wider meaning referring to the loss of...

. As humans traveled around the world they brought with them many foreign animals which disturbed these island species. Some of these were unfamiliar predators, like rat

Rat

Rats are various medium-sized, long-tailed rodents of the superfamily Muroidea. "True rats" are members of the genus Rattus, the most important of which to humans are the black rat, Rattus rattus, and the brown rat, Rattus norvegicus...

s, feral cat

Feral cat

A feral cat is a descendant of a domesticated cat that has returned to the wild. It is distinguished from a stray cat, which is a pet cat that has been lost or abandoned, while feral cats are born in the wild; the offspring of a stray cat can be considered feral if born in the wild.In many parts of...

s, and pig

Pig

A pig is any of the animals in the genus Sus, within the Suidae family of even-toed ungulates. Pigs include the domestic pig, its ancestor the wild boar, and several other wild relatives...

s; others were competitors, such as other bird species, or herbivore

Herbivore

Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

s that degraded breeding habitat. Disease can also play a role; introduced avian malaria

Malaria

Malaria is a mosquito-borne infectious disease of humans and other animals caused by eukaryotic protists of the genus Plasmodium. The disease results from the multiplication of Plasmodium parasites within red blood cells, causing symptoms that typically include fever and headache, in severe cases...

is thought to be a primary cause of many extinctions in Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

. The Dodo

Dodo

The dodo was a flightless bird endemic to the Indian Ocean island of Mauritius. Related to pigeons and doves, it stood about a meter tall, weighing about , living on fruit, and nesting on the ground....

is the most famous example of a species that was probably driven to extinction by introduced species (although human hunting also played a role), other species that were victims of introduced species were the Stephens Island Wren

Stephens Island Wren

The Stephens Island Wren or Lyall's Wren was a nocturnal, flightless, insectivorous passerine.-Habitat:...

, Poʻo-uli and the Laysan Millerbird

Laysan Millerbird

The Laysan Millerbird was a subspecies of the Millerbird, similar in appearance to the remaining subspecies, the Nihoa Millerbird. Its dorsal side was brown, and its belly was grayish...

. Many species currently threatened

Threatened species

with extinction are vulnerable to introduced species, such as the Kōkako

Kokako

The Kōkako is a forest bird which is endemic to New Zealand. It is slate-grey with wattles and a black mask. It is one of three species of New Zealand Wattlebird, the other two being the endangered Tieke and the extinct Huia...

, Black Robin

Black Robin

The Black Robin or Chatham Island Robin is an endangered bird from the Chatham Islands off the east coast of New Zealand. It is closely related to the New Zealand Robin . It was first described by Walter Buller in 1872. The binomial commemorates the New Zealand botanist Henry H. Travers...

, Mariana Crow

Mariana Crow

The Mariana Crow is a species of the crow family from the north Pacific. It is an endangered species which has steadily declined in numbers since the 1960s.-Description:...

, and the Hawaiian Duck

Hawaiian Duck

The Hawaiian Duck is a species of bird in the family Anatidae. It is endemic to the large islands of Hawaii. Some authorities treat it as an island subspecies of the Mallard, based on their capacity to produce fertile hybrids, but it appears well distinct and capability of hybridization is...

Hunting and exploitation

Humans have exploited birds for a very long time, and sometimes this exploitation has resulted in extinction. Overhunting occurred in some instances with naive

Island tameness

species unfamiliar with humans, such as the moa

Moa

The moa were eleven species of flightless birds endemic to New Zealand. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about in height with neck outstretched, and weighed about ....

of New Zealand

New Zealand

New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

, in other cases it was an industrial level of hunting

Hunting

Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...

that led to extinction. The Passenger Pigeon

Passenger Pigeon

The Passenger Pigeon or Wild Pigeon was a bird, now extinct, that existed in North America and lived in enormous migratory flocks until the early 20th century...

was once the most numerous species of bird alive (possibly ever), overhunting reduced a species that once numbered in the billions to extinction. Hunting pressure can be for food, sport, feather

Feather

Feathers are one of the epidermal growths that form the distinctive outer covering, or plumage, on birds and some non-avian theropod dinosaurs. They are considered the most complex integumentary structures found in vertebrates, and indeed a premier example of a complex evolutionary novelty. They...

s, or even come from scientists collecting museum specimens. Collection of Great Auk

Great Auk

The Great Auk, Pinguinus impennis, formerly of the genus Alca, was a large, flightless alcid that became extinct in the mid-19th century. It was the only modern species in the genus Pinguinus, a group of birds that formerly included one other species of flightless giant auk from the Atlantic Ocean...

s for museums pushed the already rare species to extinction.

The harvesting

Wildlife trade

The international wildlife trade is a serious conservation problem, addressed by the United Nations' Convention of International Trade in Endangered Species of Wild Fauna and Flora CITES, which currently has 175 member countries called Parties. The 15th meeting of the Parties took place in Doha,...

of parrot

Parrot

Parrots, also known as psittacines , are birds of the roughly 372 species in 86 genera that make up the order Psittaciformes, found in most tropical and subtropical regions. The order is subdivided into three families: the Psittacidae , the Cacatuidae and the Strigopidae...

s for the pet trade has led to many species becoming endangered. Between 1986 and 1988 two million parrots were legally imported into the US alone. Parrots are also illegally smuggled between countries, and rarer species can command high prices.

Hybridisation

Bird hybrid

A bird hybrid is a bird that has two different species as parents. The resulting bird can present with any combination of characters from the parent species, from totally identical to completely different. Usually, the bird hybrid shows intermediate characteristics between the two species...

may also endanger birds, damaging the gene stock. For example, the American Black Duck

American Black Duck

The American Black Duck is a large dabbling duck. American Black Ducks are similar to Mallards in size, and resemble the female Mallard in coloration, although the Black Duck's plumage is darker...

has been often reported hybridising with the Mallard

Mallard

The Mallard , or Wild Duck , is a dabbling duck which breeds throughout the temperate and subtropical Americas, Europe, Asia, and North Africa, and has been introduced to New Zealand and Australia....

, starting a slow decline.

Gamebird hybrids

Gamebird hybrids

Gamebird hybrids are the result of crossing species of game birds, including ducks, with each other and with domestic poultry. These hybrid species may occur both naturally or though the intervention of man....

are particularly common and many breeders produce hybrids that may be accidentally or intentionally introduced into the wild.

Other threats

Birds face a number of other threats. Pollution

Pollution

Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...

has led to serious declines in some species. The pesticide

Pesticide

DDT

DDT is one of the most well-known synthetic insecticides. It is a chemical with a long, unique, and controversial history....

was responsible for thinning egg shells in nesting birds, particularly seabird

Seabird

Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...

s and birds of prey

Bird of prey

Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....

that are high on the food chain. Seabirds are also vulnerable to oil spill

Oil spill

s, which destroy the plumage

Plumage

Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...

's waterproofing causing the bird to drown or die of hypothermia

Hypothermia

Hypothermia is a condition in which core temperature drops below the required temperature for normal metabolism and body functions which is defined as . Body temperature is usually maintained near a constant level of through biologic homeostasis or thermoregulation...

. Light pollution

Light pollution

Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...

can also have a damaging effect on some species, particularly nocturnal

Nocturnal animal

Nocturnality is an animal behavior characterized by activity during the night and sleeping during the day. The common adjective is "nocturnal"....

seabirds such as petrel

Petrel

Petrels are tube-nosed seabirds in the bird order Procellariiformes. The common name does not indicate relationship beyond that point, as "petrels" occur in three of the four families within that group...

s.

Seabirds face another threat in the form of bycatch

Bycatch

; where birds in the water become tangled in fishing nets or hooked on lines set out by long-line fisheries

Long-line fishing

. As many as 100,000 albatross

Albatross

Albatrosses, of the biological family Diomedeidae, are large seabirds allied to the procellariids, storm-petrels and diving-petrels in the order Procellariiformes . They range widely in the Southern Ocean and the North Pacific...

es are hooked and drown each year on tuna lines set out by long-line fisheries.

Birds are also threatened by high rise buildings, communications towers, and wind farms; an estimated 975 million birds a year are killed this way in the North America alone, according to the American Bird Conservancy

American Bird Conservancy

American Bird Conservancy is a non-profit membership organization with the mission of conserving native birds and their habitats throughout the Americas...

. The largest source of human-related bird death is due to glass windows, which kill 100-900 million birds a year. The next largest sources of human caused death are hunting (100+ million), house cats (100 million), cars and trucks (50 to 100 million), electric power lines (174 million), and pesticides (67 million). Birds are also killed in large quantities by flying into communication tower guidelines, usually after being attracted by tower lights. This phenomenon is called towerkill

Towerkill

Towerkill is a phenomenon in which large numbers of birds are killed by antenna towers. The U.S. Fish and Wildlife Service estimates that between 5 and 50 million birds are killed in the U.S. each year by towerkill. Window crashes, by comparison, kill between 100 and 900 million birds a year, and...

and is responsible for 5-50 million birds deaths a year. The presence of towers may seriously impact endangered species living in the vicinity.

Conservation techniques

Scientists and conservation professionals have developed a number of techniques to protect bird species. These techniques have had varying levels of success.

Captive breeding

Captive breedingis the process of breeding animals in human controlled environments with restricted settings, such as wildlife reserves, zoos and other conservation facilities; sometimes the process is construed to include release of individual organisms to the wild, when there is sufficient...

, or ex-situ conservation, has been used in a number of instances to save species from extinction. The principal is to create a viable population of a species in either zoo

Zoo

A zoological garden, zoological park, menagerie, or zoo is a facility in which animals are confined within enclosures, displayed to the public, and in which they may also be bred....

s or breeding facilities, for later reintroduction back into to the wild. As such a captive population can either serve as an insurance against the species going extinct in the wild or as a last ditch effort in situations where conservation in the wild is impossible. Captive breeding has been used to save several species from extinction, the most famous example being the California Condor

California Condor

The California Condor is a New World vulture, the largest North American land bird. Currently, this condor inhabits only the Grand Canyon area, Zion National Park, and coastal mountains of central and southern California and northern Baja California...

, a species that declined to less than thirty birds. In order to save the California Condor the decision was made to take every individual left in the wild into captivity. From these 22 individuals a breeding programme began that brought the numbers up to 273 by 2005. An even more impressive recovery was that of the Mauritius Kestrel

Mauritius Kestrel

The Mauritius Kestrel is a bird of prey from the family Falconidae endemic to the forests of Mauritius, where it is restricted to the southwestern plateau's forests, cliffs, and ravines.It is the most distinct of the Indian Ocean kestrels...

, which by 1974 had dropped to only four individuals, yet by 2006 the population was 800.

Reintroduction and translocations

Reintroductions of captive bred populations can occur to replenish wild populations of an endangered species, to create new populations or to restore a species after it has become extinct in the wild. Reintroductions helped bring the wild populations of Hawaiian Geese

Hawaiian Goose

The Nene, also known as Nēnē and Hawaiian Goose, is a species of goose endemic to the Hawaiian Islands. The official bird of the state of Hawaii, the Nene is exclusively found in the wild on the islands of Maui, Kauai and Hawaii...

from 30 birds to over 500. The Mauritius Kestrel

Mauritius Kestrel

was successfully reintroduced into the wild after its captive breeding programme. Reintroductions can be very difficult and often fail if insufficient preparations are made, as species born in captivity may lack the skills and knowledge needed for life in the wild after living in captivity. Reintroductions can also fail if the causes of a birds decline have not been adequately addressed. Attempts to reintroduce the Bali Starling

Bali Starling

The Bali Starling , also known as Rothschild’s Mynah, Bali Myna, or Bali Mynah, locally known as Jalak Bali, is a medium-sized , stocky myna, almost wholly white with a long, drooping crest, and black tips on the wings and tail. The bird has blue bare skin around the eyes, greyish legs and a yellow...

into the wild failed due to continued poaching of reintroduced birds.

The introduction of captives of unknown pedigree can pose a threat to native populations. Domestic fowl have threatened endemic species such as Gallus g. bankiva while pheasants such as the Ring-necked Pheasant and captive Cheer pheasants of uncertain origin have escaped into the wild or have been intentionally introduced. Green peafowl of similar mixed origins confiscated from local bird dealers have been released into areas with native wild birds.

Translocations involve moving populations of threatened species into areas of suitable habitat currently unused by the species. There are several reasons for doing this; the creation of secondary populations that act as an insurance against disaster, or in many cases threats faced by the original population in its current location. One famous translocation was of the Kakapo

Kakapo

The Kakapo , Strigops habroptila , also called owl parrot, is a species of large, flightless nocturnal parrot endemic to New Zealand...

of New Zealand

New Zealand

. These large flightless parrots were unable to cope with introduced predators

Introduced species

in their remaining habitat on Stewart Island, so were moved to smaller offshore islands that had been cleared of predators. From there a recovery programme has managed to maintain and eventually increase their numbers.

Habitat protection

As the loss and destruction of habitat is the most serious threat facing many bird species, conservation organisations and government agencies tasked with protecting birds work to protect areas of natural habitat. This can be achieved through purchasing land of conservation importance, setting aside land or gazetting it as a national park

National park

A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...

or other protected area

Protected area

Protected areas are locations which receive protection because of their recognised natural, ecological and/or cultural values. There are several kinds of protected areas, which vary by level of protection depending on the enabling laws of each country or the regulations of the international...

, and passing legislation

Legislation

Legislation is law which has been promulgated by a legislature or other governing body, or the process of making it...

preventing landowners from undertaking damaging land use practices, or paying them not to undertake those activities. The goals of habitat protection for birds and other threatened animals and plants often conflicts with other stakeholders, such as landowners and businesses, who can face economically damaging restrictions on their activities. Plans to protect crucial habitat for the Spotted Owl

Spotted Owl

The Spotted Owl, Strix occidentalis, is a species of true owl. It is a resident species of forests in western North America, where it nests in tree holes, old bird of prey nests, or rock crevices. Nests can be between 13 and 66 yards high and usually contain two eggs...

of North America

North America

North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

required the protection of large areas of old growth forest

Old growth forest

An old-growth forest is a forest that has attained great age , and thereby exhibits unique ecological features. An old growth forest has also usually reached a climax community...

in the western United States; this was opposed by logging companies who claimed it would cause job losses

Unemployment

Unemployment , as defined by the International Labour Organization, occurs when people are without jobs and they have actively sought work within the past four weeks...

and reduced profits.

External links

The Worlds Rarest Birds

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.

Habitat loss

Introduced species

Hunting and exploitation

Hybridisation

Other threats

Conservation techniques

Captive breeding

Reintroduction and translocations

Habitat protection

See also

External links