conservation biology
Conservation biology is the study of the conservation of nature and of Earth's biodiversity with the aim of protecting species, their habitats, and ecosystems from excessive rates of extinction and the erosion of biotic interactions. It is an i ...
bird
Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...
s. Bird conservation efforts aim to protect species and mitigate the decline of threatened bird population numbers. According to
Worldwatch Institute
The Worldwatch Institute was a globally focused environmental research organization based in Washington, D.C., founded by Lester R. Brown. Worldwatch was named as one of the top ten sustainable development research organizations by Globescan S ...
, many bird populations are currently declining worldwide, with 1,200 species facing extinction in the next century. Current estimates imply a total of nearly 11,000 extant species, suggesting that 11.6% of all bird species, a near ratio of one in nine birds, have gone extinct over the last 126,000 years of human history. The biggest cited reason surrounds
habitat loss
Habitat destruction (also termed habitat loss or habitat reduction) occurs when a natural habitat is no longer able to support its native species. The organisms once living there have either moved elsewhere, or are dead, leading to a decrease ...
bycatch
Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...
, pollution, competition and predation by pet cats,
oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...
s and
pesticide
Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...
use and
climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
. Governments, along with numerous conservation
charities
A charitable organization or charity is an organization whose primary objectives are philanthropy and social well-being (e.g. educational, religious or other activities serving the public interest or common good).
The legal definition of a cha ...
Late Quaternary prehistoric birds
Late Quaternary prehistoric birds are Bird, avian taxa that became extinct during the Late Quaternary – the Late Pleistocene or Early Holocene – and before recorded history, specifically before they could be studied alive by orni ...
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 List of extinct birds.
Historical Analysis
Prehistory to Early History
Since the
Late Pleistocene
The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...
period, it is estimated that 1,430 (95% credible interval: 1327–1544) bird extinctions have occurred.
Human
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing ...
activity has been directly attributed to almost all bird species extinctions, specifically prehistoric and early historical species. During the
Upper Paleolithic
The Upper Paleolithic (or Upper Palaeolithic) is the third and last subdivision of the Paleolithic or Old Stone Age. Very broadly, it dates to between 50,000 and 12,000 years ago (the beginning of the Holocene), according to some theories ...
period, human societies began spreading across the globe, leading to the overhunting of species and the introduction of invasive species to new environments. A particularly significant period of extinction occurred when humans colonized the islands of
Melanesia
Melanesia (, ) is a subregion of Oceania in the southwestern Pacific Ocean. It extends from New Guinea in the west to the Fiji Islands in the east, and includes the Arafura Sea.
The region includes the four independent countries of Fiji, Vanu ...
,
Polynesia
Polynesia ( , ) is a subregion of Oceania, made up of more than 1,000 islands scattered over the central and southern Pacific Ocean. The indigenous people who inhabit the islands of Polynesia are called Polynesians. They have many things in ...
, and
Micronesia
Micronesia (, ) is a subregion of Oceania, consisting of approximately 2,000 small islands in the Northwestern Pacific Ocean. It has a close shared cultural history with three other island regions: Maritime Southeast Asia to the west, Poly ...
around 4,000 years ago. According to a study published in ''
Proceedings of the National Academy of Sciences
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Scie ...
'', early Polynesian settlers are often credited with contributing to the extinction of over 1,000 bird species during this time, majority of which were non-passerine land birds.
Pre-Industrial Era into the Industrial Era
Before the
Industrial Revolution
The Industrial Revolution, sometimes divided into the First Industrial Revolution and Second Industrial Revolution, was a transitional period of the global economy toward more widespread, efficient and stable manufacturing processes, succee ...
(1750-1850), most bird species were not yet heavily impacted by habitat loss or climate change. However, overexploitation through hunting, bird collecting, as well as the introduction of invasive species became significant threats. Industrialization marked a turning point in the relationship between humans and birds. The technological growth, urban expansion, and increased emissions from industrial activity caused widespread habitat destruction and altered ecosystems. In the
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...
, species such as the white-tailed eagle (''Haliaeetus albicilla'') and cranes, for example, were recognized as more abundant before industrialization began. By the 19th century, the advent of industrial-scale hunting and urban sprawl had put pressure on many bird populations.
In North America, the Carolina parakeet (''Conuropsis carolinensis'') one of the few
parrots
Parrots (Psittaciformes), also known as psittacines (), are birds with a strong curved beak, upright stance, and clawed feet. They are classified in four families that contain roughly 410 species in 101 genus (biology), genera, found mostly in ...
indigenous to the United States, suffered from Industrial era
deforestation
Deforestation or forest clearance is the removal and destruction of a forest or stand of trees from land that is then converted to non-forest use. Deforestation can involve conversion of forest land to farms, ranches, or urban use. Ab ...
and hunting (both for its colorful feathers, and because the birds were thought to feed on crops), which helped destroy wild populations. The species' final extinction came in the early 20th century, though causes remain unclear.
Similarly, the
passenger pigeon
The passenger pigeon or wild pigeon (''Ectopistes migratorius'') is an bird extinction, extinct species of Columbidae, pigeon that was endemic to North America. Its common name is derived from the French word ''passager'', meaning "passing by" ...
(''Ectopistes migratorius'') once one of the most populous bird species in North America, was driven to extinction in the early 20th century due to relentless hunting and habitat loss. This extinction served as a stark reminder of the fragility of bird populations in the face of human intervention. The loss of such a previously abundant species helped catalyze the first major bird conservation efforts in the United States. Following the assumed extinction of passenger pigeons,
Theodore Roosevelt
Theodore Roosevelt Jr. (October 27, 1858 – January 6, 1919), also known as Teddy or T.R., was the 26th president of the United States, serving from 1901 to 1909. Roosevelt previously was involved in New York (state), New York politics, incl ...
claimed to have witnessed a small flock of the birds at his family name’s rural cabin in Virginia some 25 years after their extinction (March 24, 1900). Following this sighting, Theodore recognized the severity of the loss of this once abundant species and initiated strengthened bird advocacy legislation during his presidency in 1907. The establishment of the first Federal Bird Reserve on Pelican Island in
Florida
Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...
can be attributed to this sighting made by President Roosevelt.
Advocacy in the 20th Century
The early 20th century saw the rise of formal conservation efforts. The National Audubon Society, founded in 1905, played a key role in raising awareness about the rapid decline of bird populations, specifically in response to the exploitation of birds for the feather trade. The organization's efforts were influential in propelling early legal protections for birds. A significant achievement in favor of bird protection was the passage of the Migratory Bird Treaty Act of 1918. This act provided international protection for migratory bird species between the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
,
Canada
Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
,
Mexico
Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...
,
Japan
Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...
, and
Russia
Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...
.
From the 1920s to 1950s, bird advocacy gained further strength. In 1934, the Duck Stamp Act was passed. It sought to fund the protection of wetlands using hunter fees. Additionally, during the
Great Depression
The Great Depression was a severe global economic downturn from 1929 to 1939. The period was characterized by high rates of unemployment and poverty, drastic reductions in industrial production and international trade, and widespread bank and ...
,
New Deal
The New Deal was a series of wide-reaching economic, social, and political reforms enacted by President Franklin D. Roosevelt in the United States between 1933 and 1938, in response to the Great Depression in the United States, Great Depressi ...
programs including the Civilian Conservation Corps preserved wildlife refuges, providing birds a thriving environment for bird species.
Birdwatching
Birdwatching, or birding, is the observing of birds, either as a recreational activity or as a form of citizen science. A birdwatcher may observe by using their naked eye, by using a visual enhancement device such as binoculars or a telescop ...
gained popularity within this timeframe, too, in large part thanks to Roger Tory Peterson’s groundbreaking field guides. Finally, Rachel Carson's early works began to clarify the relationship between healthy bird populations and a healthy planet. All of these factors laid more solid groundwork for the continuation of advocacy for birds.
The 1960s were a particularly pivotal era in favor of bird conservation. The publication of Rachel Carson’s ''
Silent Spring
''Silent Spring'' is an environmental science book by Rachel Carson. Published on September 27, 1962, the book documented the environmental harm caused by the indiscriminate use of DDT, a pesticide used by soldiers during World War II. Carson acc ...
'' (1962) aided in exposing widespread dangers of pesticide use, particularly DDT, on bird populations. Her groundbreaking work demonstrated how DDT led to the thinning of eggshells in species like the
bald eagle
The bald eagle (''Haliaeetus leucocephalus'') is a bird of prey found in North America. A sea eagle, it has two known subspecies and forms a species pair with the white-tailed eagle (''Haliaeetus albicilla''), which occupies the same niche ...
(''Haliaeetus leucocephalus'') and
peregrine falcon
The peregrine falcon (''Falco peregrinus''), also known simply as the peregrine, is a Cosmopolitan distribution, cosmopolitan bird of prey (raptor) in the family (biology), family Falconidae renowned for its speed. A large, Corvus (genus), cro ...
(''Falco peregrinus''), resulting in reproductive failures. Carson’s book ignited a broader environmental movement, leading to significant policy changes, and the eventual DDT ban. The Environmental Protection Agency enforced a generalized ban on DDT pesticides in 1972. Bald eagles made a famous comeback during the “dirty sixties” thanks to this ban, along with the brown pelican (''Pelecanus occidentalis'') and peregrine falcon.
By the 1980s, the global conservation movement gained further momentum. Organizations like
BirdLife International
BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...
played an increasingly vital role in establishing international frameworks for bird protection. This included efforts to protect critical habitats, such as wetland areas, and to monitor at-risk species. Additionally, the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...
(IUCN) developed the Red List of Threatened Species, which continues to serve as an important tool for identifying and tracking species at risk of extinction, including many bird species.
Threats to birds
Habitat Loss
The most critical threat facing threatened birds is the destruction and fragmentation of habitat. The loss of forests, plains and other natural systems into agriculture, mines, and urban developments, the draining of
swamp
A swamp is a forested wetland.Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p. Swamps are considered to be transition zones because both land and water play a role in ...
s and other
wetland
A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
s, and
logging
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucksisland biogeography). The loss of
tropical rainforest
Tropical rainforests are dense and warm rainforests with high rainfall typically found between 10° north and south of the Equator. They are a subset of the tropical forest biome that occurs roughly within the 28° latitudes (in the torrid zo ...
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 (''Campephilus principalis'') (disputed because of "rediscovery"), Bachman's warbler (''Vermivora bachmanii''), and the dusky seaside sparrow (''Ammospiza maritima nigrescens'').
Climate Change
Climate change
Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...
is a catalyst for the worrying downward trend of bird populations globally. The speed of human-caused climate change is currently unprecedented, leading bird species into continuously unadaptable circumstances. The American Bird Conservancy states there is a clear and direct comparison between bird population decline and climate change, stating that “ rming temperatures are changing where birds live, the timing of their migration patterns and egg laying, and even the sizes and shapes of their bodies.”
Direct impacts
It has been observed that most North American bird species have been recognized over the prior few decades to have shifted their breeding ranges irregularly due to climate change. Migratory birds are more prone to the effects of climate change, leading to shifts in time migratory patterns. It is predicted in the coming years that mountainous birds will even lose suitable migratory habitats due to rising temperatures at higher elevations. On top of these migratory shifts, global warming has been predicted to be changing size and wing length proportionally in all bird species. It is presumed that with rising temperatures, smaller birds maintain better competitive fitness thanks to their easier heat dispersal compared to their larger counterparts within the same species.
Indirect impacts
Indirect impacts of climate change on birds include increased drought and fires, rising-sea levels, increased disease, phenological mismatch, and uncommon interactions between species. Increase in drought leads to increased fires, destroying nesting ground and fragmenting specifically sagebrush ecosystems. Rise in sea-levels provides similar altercations for marsh-nesting birds. Nesting sites disappear as sea-levels rise, eliminating habitats for nesting parents and young to continue species. Phenological mismatch occurs due to rising temperatures shifting migratory timeframes but not quickly enough, altering the life cycle events in interacting species at different rates.
Pollution
Birds are afflicted by numerous pollutants including marine oil pollution, plastic pollution, light pollution, sound pollution, air pollution, and pesticides to name a major few. Plastic pollution serves a major detriment to birds, mainly marine birds. Many marine birds suffer from entanglement, nutritional deprivation, and gut damage due to ingested plastic litter.
Introduced species
Historically the threat posed by
introduced species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived ther ...
has probably caused the most extinctions of birds, particularly on islands. most prehistoric human caused extinctions were insular as well. Many island species
evolved
Evolution is the change in the heritable Phenotypic trait, characteristics of biological populations over successive generations. It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, re ...
in the absence of predators and consequently lost many anti-predator behaviors. 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
Rats are various medium-sized, long-tailed rodents. Species of rats are found throughout the order Rodentia, but stereotypical rats are found in the genus ''Rattus''. Other rat genera include '' Neotoma'' (pack rats), '' Bandicota'' (bandicoo ...
s,
feral cat
A feral cat or a stray cat is an unowned domestic cat (''Felis catus'') that lives outdoors and avoids human contact; it does not allow itself to be handled or touched, and usually remains hidden from humans. Feral cats may breed over dozens ...
s, and pigs; others were competitors, such as other bird species, or
herbivore
A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...
s that degraded breeding habitat. Disease can also play a role; introduced avian
malaria
Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...
is thought to be a primary cause of many extinctions in
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
. The
dodo
The dodo (''Raphus cucullatus'') is an extinction, extinct flightless bird that was endemism, endemic to the island of Mauritius, which is east of Madagascar in the Indian Ocean. The dodo's closest relative was the also-extinct and flightles ...
(''Raphus cucullatus'') 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 Lyall's wren (''Traversia lyalli''), poʻo-uli (''Melamprosops phaeosoma''), and the Laysan millerbird (''Acrocephalus familiaris familiaris'') . Many species currently threatened with extinction are vulnerable to introduced species, such as the kōkako (''Callaeas'' species),
black robin
The black robin or Chatham Island robin (Moriori language, Moriori: , ; ''Petroica traversi'') is an endangered bird from the Chatham Islands off the east coast of New Zealand. It is closely related to the South Island robin (''P. australis'') ...
''(Petroica traversi)'', Mariana crow (''Corvus kubaryi''), and the
Hawaiian duck
The Hawaiian duck (''Anas wyvilliana'') or koloa is a species of bird in the family Anatidae that is endemic to the large islands of Hawaii. Taxonomically, the koloa is closely allied with the mallard (''A. platyrhynchos''). It differs in that i ...
(''Anas wyvilliana'').
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 a naive species unfamiliar with humans, such as the moa of
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
, in other cases it was an industrial level of
hunting
Hunting is the Human activity, human practice of seeking, pursuing, capturing, and killing wildlife or feral animals. The most common reasons for humans to hunt are to obtain the animal's body for meat and useful animal products (fur/hide (sk ...
that led to extinction. The
passenger pigeon
The passenger pigeon or wild pigeon (''Ectopistes migratorius'') is an bird extinction, extinct species of Columbidae, pigeon that was endemic to North America. Its common name is derived from the French word ''passager'', meaning "passing by" ...
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
Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an exa ...
s, or even come from scientists collecting museum specimens. Collection of
great auk
The great auk (''Pinguinus impennis''), also known as the penguin or garefowl, is an Extinction, extinct species of flightless bird, flightless auk, alcid that first appeared around 400,000 years ago and Bird extinction, became extinct in the ...
s for museums pushed the already rare species to extinction.
parrot
Parrots (Psittaciformes), also known as psittacines (), are birds with a strong curved beak, upright stance, and clawed feet. They are classified in four families that contain roughly 410 species in 101 genus (biology), genera, found mostly in ...
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.
Organized entrapment of birds takes place today across the globe, specifically in
Latin America
Latin America is the cultural region of the Americas where Romance languages are predominantly spoken, primarily Spanish language, Spanish and Portuguese language, Portuguese. Latin America is defined according to cultural identity, not geogr ...
,
Asia
Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...
, and
Africa
Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...
. The demand for exotic pet birds in the United States drives capture in Bolivia and Mexico, with a supposed over 22,000 individuals of 31 parrot species illegally traded under Bolivian law every year and an estimated 65,000–78,500 parrots captured every year in Mexico. This poaching continues due to the potential profits, with rarer species selling for up to $1,000 each when caught illegally.
Plume trade
Plume hunting is the hunting of wild birds to harvest their decorative
feather
Feathers are epidermal growths that form a distinctive outer covering, or plumage, on both avian (bird) and some non-avian dinosaurs and other archosaurs. They are the most complex integumentary structures found in vertebrates and an exa ...
s. More decorative plumes, which were sold for use as ornamentation particularly in hat-making, were more sought after in the trade. While the plume trade is not necessarily an large ongoing threat to birds, it was in its height in the late 19th century into the early 20th century until protective efforts were instated.
Hybridization
Hybridization may also endanger birds, damaging the gene stock. For example, the American black duck (''Anas rubripes'') has been often reported hybridizing with the
mallard
The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa. It has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...
(''Anas platyrhynchos''), starting a slow decline in the rarer ''A. rubripes''.
Gamebird hybrids 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 is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...
has led to serious declines in some species. Increasingly large volumes of
plastic waste
Plastic pollution is the accumulation of plastic objects and particles (e.g. plastic bottles, bags and microbeads) in the Earth's environment that adversely affects humans, wildlife and their habitat. Plastics that act as pollutants are cate ...
are being transported by wind and ocean currents throughout the planet, and mistaken ingestion by many species is eventually fatal.
Seabird
Seabirds (also known as marine birds) are birds that are adaptation, adapted to life within the marine ecosystem, marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent ...
s are also vulnerable to
oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially the marine ecosystem, due to human activity, and is a form of pollution. The term is usually given to marine oil spills, where oil is released into th ...
s, which destroy the
plumage
Plumage () is a layer of feathers that covers a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage differ between species and subspecies and may vary with age classes. Within species, there can b ...
's waterproofing, causing the birds to drown or die of
hypothermia
Hypothermia is defined as a body core temperature below in humans. Symptoms depend on the temperature. In mild hypothermia, there is shivering and mental confusion. In moderate hypothermia, shivering stops and confusion increases. In severe ...
.
Light pollution
Light pollution is the presence of any unwanted, inappropriate, or excessive artificial Visible spectrum, lighting. In a descriptive sense, the term ''light pollution'' refers to the effects of any poorly implemented lighting sources, during the ...
can also have a damaging effect on some species, particularly
nocturnal
Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite.
Nocturnal creatur ...
seabirds such as
petrel
Petrels are tube-nosed seabirds in the phylogenetic order Procellariiformes.
Description
Petrels are a monophyletic group of marine seabirds, sharing a characteristic of a nostril arrangement that results in the name "tubenoses". Petrels enco ...
s. The
pesticide
Pesticides are substances that are used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...
DDT was responsible for thinning egg shells in nesting birds, particularly seabirds and
birds of prey
Birds of prey or predatory birds, also known as (although not the same as) raptors, are hypercarnivorous bird species that actively predation, hunt and feed on other vertebrates (mainly mammals, reptiles and smaller birds). In addition to speed ...
that are high on the food chain. The use of pesticides continues to harm birds, especially
insectivore
file:Common brown robberfly with prey.jpg, A Asilidae, robber fly eating a hoverfly
An insectivore is a carnivore, carnivorous animal or plant which eats insects. An alternative term is entomophage, which can also refer to the Entomophagy ...
s like
swallow
The swallows, martins, and saw-wings, or Hirundinidae are a family of passerine songbirds found around the world on all continents, including occasionally in Antarctica. Highly adapted to aerial feeding, they have a distinctive appearance. The ...
s that have lost a food source from the use of
insecticide
Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. The major use of insecticides is in agriculture, but they are also used in home and garden settings, i ...
s in agriculture. A particularly dangerous class of pesticides is the seed-coating
neonicotinoid
Neonicotinoids (sometimes shortened to neonics ) are a class of neuro-active insecticides chemically similar to nicotine, developed by scientists at Royal Dutch Shell, Shell and Bayer in the 1980s.
Neonicotinoids are among the widest-used insecti ...
s. Neonicotinoids include a
neurotoxin
Neurotoxins are toxins that are destructive to nervous tissue, nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insult (medical), insultsSpencer 2000 that can adversely affect function ...
that bioaccumulates in the tissue of birds and is associated with impairment of reproduction.
Seabirds
Seabirds (also known as marine birds) are birds that are 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 envi ...
face another threat in the form of
bycatch
Bycatch (or by-catch), in the fishing industry, is a fish or other marine species that is caught unintentionally while fishing for specific species or sizes of wildlife. Bycatch is either the wrong species, the wrong sex, or is undersized or juve ...
, where birds in the water become tangled in fishing nets or hooked on lines set out by long-line fisheries. As many as 100,000
albatross
Albatrosses, of the biological family Diomedeidae, are large seabirds related to the procellariids, storm petrels, and diving petrels in the order Procellariiformes (the tubenoses). They range widely in the Southern Ocean and the North Paci ...
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 other human-related activities and structures; estimates vary from about 3.5 to 975 million birds a year in the North America alone. 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 and is responsible for 5–50 million birds deaths a year. Similarly, natural gas flaring can attract and kill large numbers of birds. Approximately 7,500 migrating songbirds were attracted to and killed by the flare at the
liquefied natural gas
Liquefied natural gas (LNG) is natural gas (predominantly methane, CH4, with some mixture of ethane, C2H6) that has been cooled to liquid form for ease and safety of non-pressurized storage or transport. It takes up about 1/600th the volume o ...
terminal in Saint John, New Brunswick, Canada on September 13, 2013. Similar incidents have occurred at flares on offshore oil and gas installations.
The recent growth in the renewable energy industry is also increasing the threat to birds farther away from dense human population centers. As of late 2019, the capacity of
wind power
Wind power is the use of wind energy to generate useful work. Historically, wind power was used by sails, windmills and windpumps, but today it is mostly used to generate electricity. This article deals only with wind power for electricity ge ...
in the U.S. reached 100 GW (
gigawatt
The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named in honor ...
). Studies conducted at a variety of farms found fewer than 14, and typically fewer than 4, direct bird deaths per year per installed
megawatt
The watt (symbol: W) is the unit of Power (physics), power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantification (science), quantify the rate of Work ...
; suggesting cumulative mortality is approaching the order of a million individuals annually. Migrating songbirds appeared to be the most strongly impacted in some studies. The primary impact of commercial solar farms – the majority utilizing
photovoltaic
Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially ...
collectors which are mounted near the ground – is from extensive land clearing and increases in long-distance power transmission infrastructure. In 2015, biologists working for the state of
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
concentrated solar power
Concentrated solar power (CSP, also known as concentrating solar power, concentrated solar thermal) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight into a receiver. Electricity is generated whe ...
demonstration plant in the span of a year; "many of them burned alive while flying near the tower collector where air temperatures reached up to 1,000 degrees Fahrenheit."
According to a 2018 ''
Nature
Nature is an inherent character or constitution, particularly of the Ecosphere (planetary), ecosphere or the universe as a whole. In this general sense nature refers to the Scientific law, laws, elements and phenomenon, phenomena of the physic ...
'' paper studying trends in global
waterbird
A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...
populations, ineffective
governance
Governance is the overall complex system or framework of Process, processes, functions, structures, Social norm, rules, Law, laws and Norms (sociology), norms born out of the Interpersonal relationship, relationships, Social interaction, intera ...
is a major driver of biodiversity loss in wetlands, highlighting the importance of political and institutional factors in conservation outcomes.
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 breeding
Captive breeding, also known as captive propagation, is the process of keeping plants or animals in controlled environments, such as wildlife reserves, zoos, Botanical garden, botanic gardens, and other Conservation biology, conservation facilitie ...
, or ''ex-situ'' conservation, has been used in a number of instances to save species from extinction. The principle is to create a viable population of a species in either zoos or breeding facilities, for later reintroduction back into the wild. 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, 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 program began that brought the numbers up to 273 by 2005. An even more impressive recovery was that of the Mauritius kestrel (''Falco punctatus''), which by 1974 had dropped to only four individuals, yet by 2006 the population increased to 800.Jones, C.G.; Heck, W.; Lewis, R.E.; Mungroo, Y.; Slade, G.; Cade, T. (1995). " The restoration of the Mauritius kestrel ''Falco punctatus'' population." ''Ibis'' 137(Suppl.1): 173–180.
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 (nene) (''Branta sandvicensis)'' from 30 birds to over 500. The 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
The Bali myna (''Leucopsar rothschildi''), also known as Rothschild's mynah, Bali starling, or Bali mynah, locally known as jalak Bali, is a medium-sized (up to long), stocky myna, almost wholly white with a long, drooping crest, and black ti ...
(''Leucopsar rothschildi'') into the wild failed due to continued poaching of reintroduced birds.
The introduction of captives of unknown pedigree can also 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
The common pheasant (''Phasianus colchicus''), ring-necked pheasant, or blue-headed pheasant, is a bird in the pheasant family (Phasianidae). The genus name comes from Latin ''phasianus'' 'pheasant'. The species name ''colchicus'' is Latin for ...
(''Phasianus colchicus'') and captive cheer pheasants (''Catreus wallichii'') of uncertain origin have escaped into the wild or have been intentionally introduced. Green peafowl (''Pavo muticus'') 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
kākāpō
The kākāpō (; : ; ''Strigops habroptilus''), sometimes known as the owl parrot or owl-faced parrot, is a species of large, nocturnal, ground-dwelling parrot of the superfamily Strigopoidea. It is endemic to New Zealand.
Kākāpō can be u ...
(''Strigops habroptilus'') of
New Zealand
New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...
. These large flightless parrots were unable to cope with introduced predators in their remaining habitat on
Stewart Island
Stewart Island (, ' glowing skies', officially Stewart Island / Rakiura, formerly New Leinster) is New Zealand's third-largest island, located south of the South Island, across Foveaux Strait.
It is a roughly triangular island with a la ...
, so were moved to smaller offshore islands that had been cleared of predators. From there a recovery program 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 organizations 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
A national park is a nature park designated for conservation (ethic), conservation purposes because of unparalleled national natural, historic, or cultural significance. It is an area of natural, semi-natural, or developed land that is protecte ...
or other
protected area
Protected areas or conservation areas are locations which receive protection because of their recognized natural or cultural values. Protected areas are those areas in which human presence or the exploitation of natural resources (e.g. firewood ...
, and passing
legislation
Legislation is the process or result of enrolling, enacting, or promulgating laws by a legislature, parliament, or analogous governing body. Before an item of legislation becomes law it may be known as a bill, and may be broadly referred ...
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 (''Strix occidentalis'') of
North America
North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...
required the protection of large areas of
old growth forest
An old-growth forest or primary forest is a forest that has developed over a long period of time without disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organization of the United Natio ...
in the western United States; this was opposed by logging companies who claimed it would cause job losses and reduced profits.Simberloff, D. (1987). "The Spotted Owl Fracas: Mixing Academic, Applied, and Political Ecology" ''Ecology'' 68(4): 766–772.
See also
*
Avicide
An avicide is any substance (normally a chemical) used to kill birds.
Commonly used avicides include strychnine (also used as rodenticide and predacide), DRC-1339 (3-chloro-4-methylaniline hydrochloride, Starlicide) and CPTH (3-chloro-p-toluidi ...
*
Berne Convention on the Conservation of European Wildlife and Natural Habitats
Bern (), or Berne (), ; ; ; . is the '' de facto'' capital of Switzerland, referred to as the " federal city".; ; ; . According to the Swiss constitution, the Swiss Confederation intentionally has no "capital", but Bern has governmental i ...
BirdLife International
BirdLife International is a global partnership of non-governmental organizations that strives to conserve birds and their habitats. BirdLife International's priorities include preventing extinction of bird species, identifying and safeguarding i ...