The passenger pigeon or wild pigeon is an extinct species of pigeon, endemic to North America. Its common name is derived from the French word passager, meaning "passing by", due to the migratory habits of the species; the scientific name refers to its migratory characteristics. The morphologically similar mourning dove was long thought to be its closest relative, the two were at times confused, but genetic analysis has shown that the genus Patagioenas is more related to it than the Zenaida doves; the passenger pigeon was sexually dimorphic in coloration. The male was 390 to 410 mm in length gray on the upperparts, lighter on the underparts, with iridescent bronze feathers on the neck, black spots on the wings; the female was 380 to 400 mm, was duller and browner than the male overall. The juvenile was similar without iridescence, it inhabited the deciduous forests of eastern North America and was recorded elsewhere, but bred around the Great Lakes. The pigeon migrated in enormous flocks searching for food and breeding grounds, was once the most abundant bird in North America, numbering around 3 billion, up to 5 billion, “at the time of the discovery of America,” according to A. W. Schorger.
Though one genetic study concluded that the bird was not always that abundant, that the population size fluctuated over time, a more recent study found evidence that this was not the correct interpretation of the genetic data, instead concluded that the passenger pigeon population size had been stable for at least 20,000 years prior to "its 19th-century decline and eventual extinction." A fast flyer, the passenger pigeon could reach a speed of 100 km/h. The bird fed on mast, fruits and invertebrates, it practiced communal roosting and communal breeding, its extreme gregariousness may be linked with searching for food and predator satiation. Passenger pigeons were hunted by Native Americans, but hunting intensified after the arrival of Europeans in the 19th century. Pigeon meat was commercialized as cheap food, resulting in hunting on a massive scale for many decades. There were several other factors contributing to the decline and subsequent extinction of the species, including shrinking of the large breeding populations necessary for preservation of the species and widespread deforestation, which destroyed its habitat.
A slow decline between about 1800 and 1870 was followed by a rapid decline between 1870 and 1890. The last confirmed wild bird is thought to have been shot in 1901; the last captive birds were divided in three groups around the turn of the 20th century, some of which were photographed alive. Martha, thought to be the last passenger pigeon, died on September 1914, at the Cincinnati Zoo; the eradication of this species is a notable example of anthropogenic extinction. Swedish naturalist Carl Linnaeus coined the binomial name Columba macroura for both the mourning dove and the passenger pigeon in the 1758 edition of his work Systema Naturae, wherein he appears to have considered the two identical; this composite description cited accounts of these birds in two pre-Linnean books. One of these was Mark Catesby's description of the passenger pigeon, published in his 1731 to 1743 work Natural History of Carolina and the Bahama Islands, which referred to this bird as Palumbus migratorius, was accompanied by the earliest published illustration of the species.
Catesby's description was combined with the 1743 description of the mourning dove by George Edwards, who used the name C. macroura for that bird. There is nothing to suggest Linnaeus saw specimens of these birds himself, his description is thought to be derivative of these earlier accounts and their illustrations. In his 1766 edition of Systema Naturae, Linnaeus dropped the name C. macroura, instead used the name C. migratoria for the passenger pigeon, C. carolinensis for the mourning dove. In the same edition, Linnaeus named C. canadensis, based on Turtur canadensis, as used by Mathurin Jacques Brisson in 1760. Brisson's description was shown to have been based on a female passenger pigeon. In 1827 William John Swainson moved the passenger pigeon from the genus Columba to the new monotypic genus Ectopistes, due in part to the length of the wings and the wedge shape of the tail. In 1906 Outram Bangs suggested that because Linnaeus had wholly copied Catesby's text when coining C. macroura, this name should apply to the passenger pigeon, as E. macroura.
In 1918 Harry C. Oberholser suggested that C. canadensis should take precedence over C. migratoria, as it appeared on an earlier page in Linnaeus' book. In 1952 Francis Hemming proposed that the International Commission on Zoological Nomenclature secure the specific name macroura for the mourning dove, the name migratorius for the passenger pigeon, since this was the intended use by the authors on whose work Linnaeus had based his description; this was accepted by the ICZN, which used its plenary powers to designate the species for the respective names in 1955. The passenger pigeon was a member of Columbidae, its closest living relatives were long thought to be the Zenaida doves, based on morphological grounds the physically similar mourning dove. It was suggested that the mourning dove belonged to the genus Ectopistes and was listed as E. carolinensis by some authors, including Thomas Mayo Brewer. The passenger pigeon was descended from Zenaida pigeons that had adapted to the woodlands on the plains of centra
The black robin or Chatham Island robin is an endangered bird from the Chatham Islands off the east coast of New Zealand. It is related to the South Island robin, it was first described by Walter Buller in 1872. Unlike its mainland counterparts, its flight capacity is somewhat reduced. Evolution in the absence of mammalian predators made it vulnerable to introduced species such as cats and rats, it became extinct on the main island of the Chatham group before 1871, being restricted to Little Mangere Island thereafter; the first mention of the black robin in science was at a presentation given by William Travers at the Wellington Philosophical Society in 1871. He presented the findings of his son, Henry Travers, who had visited the Chatham Islands to investigate their fauna. Although Henry Travers' notes on his visit were published the following year, it was the publication of Walter Buller a month, considered the species' official description; the black robin is a sparrow-sized bird measuring 10 -- 15 cm.
Its plumage is entirely brownish-black, with a black bill and brownish-black yellow-soled feet. Females are slightly smaller than males. Male songs are a simple phrase of 5 to 7 notes, its call is a high pitched single note. Their eyes are dark brown; the birds will moult between March. Black robins live in low-altitude scrub forest remnants, they are insectivorous, feed on the forest floor or on low branches. Black robins like to nest in hollow trees and tree stumps, they live in woody vegetation, under the canopy of trees - beneath the branches of the akeake trees. To shelter from the strong winds and rough seas around the islands they spend a lot of its time in the lower branches of the forest, they prefer flat areas of the forest with deep litter layers. Black robins are territorial. Males will defend their areas. Females have been known to chase away other females, they do not fly long distances. Black robins forage in the leaf litter on the ground for grubs, cockroaches and worms. Black robins will have good night vision.
Black robins will start to breed at two years of age. The female robin will make the nest and while she lays and incubates the eggs the male will feed the female for a rest. Eggs are laid between late December. A second clutch may be laid; the clutch size varies from one to three eggs. Eggs are creamy in colour with purple splotches; when the eggs are laid the female will sit on them to keep them warm until they hatch in about 18 days. Both parents will help to feed the chicks. Chicks spend the first day or two, after leaving the nest, on the ground - a dangerous place to be for it with predators that are there. Young robins stay in the nest for about 23 days after hatching, but after leaving the nest the parents will continue to feed them until they are about 65 days old; this period of parental care is longer than would be expected for a bird of its size. Survivorship between 1980 and 1991 indicates a mean life expectancy of four years. "Old Blue" however, the sole breeding female in 1980, lived for over 14 years.
Some can live from 6 to 13 years. There are now around 250 black robins, they were saved from extinction by Don Merton and his Wildlife Service team, by "Old Blue", the last remaining fertile female. The remaining birds were moved to Mangere Island; the team increased the annual output of Old Blue by removing the first clutch every year and placing the eggs in the nest of the Chatham race of the tomtit, a technique known as cross-fostering. The tomtits raised the first brood, the black robins, having lost their eggs and raised another brood. Many females laid eggs on the rims of nests. Human conservationists pushed the eggs back into the nests where they were incubated and hatched successfully; the maladaptive gene causing this behaviour spread until over 50% of females laid rim eggs. Humans stopped pushing eggs back in time to prevent the gene spreading to all birds which could have made the birds dependent on humans indefinitely. After human intervention stopped rim laying became less frequent, but 9% of birds still laid rim eggs as of 2011.
Conservationists have faced some criticism that they may inadvertently do harm if they allow organisms with deleterious traits to survive and perpetuate what is maladaptive. All of the surviving black robins are descended from "Old Blue", giving little genetic variation among the population and creating the most extreme population bottleneck possible. However, this does not seem to have caused inbreeding problems, leading to speculation that the species has passed through several such population reductions in its evolutionary past and has lost any alleles that could cause deleterious inbreeding effects, it was assumed that the minimum viable population protecting from inbreeding depression was around 50 individuals, but this is now known to be an inexact average, with the actual numbers being below 10 in reproducing small-island species such as the black robin, to several hundred in long-lived continental species with a wide distribution. Nest predation by introduced common starlings is the most common cause of nesting failure for black robins on Rangatira Island, with 21% of nests failing due to starlings.
Incidences of failure caused by starlings are more common when black robins nest in cavities compared to open nests. The species is still endangered, but now numbers around 250 individuals in
The Arctic fox known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome. It is well adapted to living in cold environments, is best known for its thick, warm fur, used as camouflage. On average, Arctic foxes only live 3–4 years in the wild, its body length ranges from 46 to 68 cm, with a rounded body shape to minimize the escape of body heat. The Arctic fox preys on many small creatures such as lemmings, ringed seal pups, fish and seabirds, it eats carrion, berries and insects and other small invertebrates. Arctic foxes form monogamous pairs during the breeding season and they stay together to raise their young in complex underground dens. Other family members may assist in raising their young. Natural predators of the Arctic fox are golden eagles, polar bears, red foxes and grizzly bears. Arctic foxes must endure a temperature difference of up to 90-100 °C between the external environment and their internal core temperature.
To prevent heat loss, the Arctic fox curls up tucking its legs and head under its body and behind its furry tail. This position gives the fox the smallest surface area to volume ratio and protects the least insulated areas. Arctic foxes stay warm by getting out of the wind and residing in their dens. Although the Arctic foxes are active year-round and do not hibernate, they attempt to preserve fat by reducing their locomotor activity, they build up their fat reserves in the autumn, sometimes increasing their body weight by more than 50%. This provides greater insulation during a source of energy when food is scarce. In the spring, the Arctic fox's attention switches to reproduction and a home for their potential offspring, they live in large dens in frost-free raised ground. These are complex systems of tunnels covering as much as 1,000 m2 and are in eskers, long ridges of sedimentary material deposited in glaciated regions; these dens are used by many generations of foxes. Arctic foxes tend to select dens that are accessible with many entrances, that are clear from snow and ice making it easier to burrow in.
The Arctic fox builds and chooses dens that face southward towards the sun, which makes the den warmer. Arctic foxes prefer large, maze-like dens for predator evasion and a quick escape when red foxes are in the area. Natal dens are found in rugged terrain, which may provide more protection for the pups. But, the parents will relocate litters to nearby dens to avoid predators; when red foxes are not in the region, Arctic foxes will use dens that the red fox occupied. Shelter quality is more important to the Arctic fox; the main prey in the tundra is lemmings, why the white fox is called the “lemming fox.” The white fox's reproduction rates reflect the lemming population density, which cyclically fluctuates every 3–5 years. When lemmings are abundant, the white fox can give birth to 18 pups, but they do not reproduce when food is scarce; the “coastal fox” or blue fox lives in an environment where food availability is consistent, they will have up to 5 pups every year. Breeding takes place in April and May, the gestation period is about 52 days.
Litters may contain as many as 25. The young are weaned by 9 weeks of age. Arctic foxes are monogamous and both parents will care for the offspring; when predators and prey are abundant, Arctic foxes are more to be promiscuous and display more complex social structures. Larger packs of foxes consisting of breeding or non-breeding males or females can guard a single territory more proficiently to increase pup survival; when resources are scarce, competition increases and the number of foxes in a territory decreases. On the coasts of Svalbard, the frequency of complex social structures is larger than inland foxes that remain monogamous due to food availability. In Scandinavia, there are more complex social structures compared to other populations due to the presence of the red fox. Conservationists are supplying the declining population with supplemental food. One unique case, however, is Iceland; the older offspring remain within their parent's territory though predators are absent and there are fewer resources, which may indicate kin selection in the fox.
Arctic foxes eat any small animal they can find, including lemmings, other rodents, birds, eggs and carrion. They scavenge on carcasses left by larger predators such as wolves and polar bears, in times of scarcity eat their feces. In areas where they are present, lemmings are their most common prey, a family of foxes can eat dozens of lemmings each day. In some locations in northern Canada, a high seasonal abundance of migrating birds that breed in the area may provide an important food source. On the coast of Iceland and other islands, their diet consists predominantly of birds. During April and May, the Arctic fox preys on ringed seal pups when the young animals are confined to a snow den and are helpless, they consume berries and seaweed, so they may be considered omnivores. This fox is a significant bird-egg predator, consuming eggs of all except the largest tundra bird species; when food is overabundant, the Arctic fox buries the surplus as a reserve. Arctic foxes survive harsh winters and food scarcity
New Zealand is a sovereign island country in the southwestern Pacific Ocean. The country geographically comprises two main landmasses—the North Island, the South Island —and around 600 smaller islands. New Zealand is situated some 2,000 kilometres east of Australia across the Tasman Sea and 1,000 kilometres south of the Pacific island areas of New Caledonia and Tonga; because of its remoteness, it was one of the last lands to be settled by humans. During its long period of isolation, New Zealand developed a distinct biodiversity of animal and plant life; the country's varied topography and its sharp mountain peaks, such as the Southern Alps, owe much to the tectonic uplift of land and volcanic eruptions. New Zealand's capital city is Wellington. Sometime between 1250 and 1300, Polynesians settled in the islands that were named New Zealand and developed a distinctive Māori culture. In 1642, Dutch explorer Abel Tasman became the first European to sight New Zealand. In 1840, representatives of the United Kingdom and Māori chiefs signed the Treaty of Waitangi, which declared British sovereignty over the islands.
In 1841, New Zealand became a colony within the British Empire and in 1907 it became a dominion. Today, the majority of New Zealand's population of 4.9 million is of European descent. Reflecting this, New Zealand's culture is derived from Māori and early British settlers, with recent broadening arising from increased immigration; the official languages are English, Māori, NZ Sign Language, with English being dominant. A developed country, New Zealand ranks in international comparisons of national performance, such as quality of life, education, protection of civil liberties, economic freedom. New Zealand underwent major economic changes during the 1980s, which transformed it from a protectionist to a liberalised free-trade economy; the service sector dominates the national economy, followed by the industrial sector, agriculture. Nationally, legislative authority is vested in an elected, unicameral Parliament, while executive political power is exercised by the Cabinet, led by the prime minister Jacinda Ardern.
Queen Elizabeth II is the country's monarch and is represented by a governor-general Dame Patsy Reddy. In addition, New Zealand is organised into 11 regional councils and 67 territorial authorities for local government purposes; the Realm of New Zealand includes Tokelau. New Zealand is a member of the United Nations, Commonwealth of Nations, ANZUS, Organisation for Economic Co-operation and Development, ASEAN Plus Six, Asia-Pacific Economic Cooperation, the Pacific Community and the Pacific Islands Forum. Dutch explorer Abel Tasman sighted New Zealand in 1642 and named it Staten Land "in honour of the States General", he wrote, "it is possible that this land joins to the Staten Land but it is uncertain", referring to a landmass of the same name at the southern tip of South America, discovered by Jacob Le Maire in 1616. In 1645, Dutch cartographers renamed the land Nova Zeelandia after the Dutch province of Zeeland. British explorer James Cook subsequently anglicised the name to New Zealand. Aotearoa is the current Māori name for New Zealand.
It is unknown whether Māori had a name for the whole country before the arrival of Europeans, with Aotearoa referring to just the North Island. Māori had several traditional names for the two main islands, including Te Ika-a-Māui for the North Island and Te Waipounamu or Te Waka o Aoraki for the South Island. Early European maps labelled the islands North and South. In 1830, maps began to use North and South to distinguish the two largest islands and by 1907 this was the accepted norm; the New Zealand Geographic Board discovered in 2009 that the names of the North Island and South Island had never been formalised, names and alternative names were formalised in 2013. This set the names as North Island or Te Ika-a-Māui, South Island or Te Waipounamu. For each island, either its English or Māori name can be used. New Zealand was one of the last major landmasses settled by humans. Radiocarbon dating, evidence of deforestation and mitochondrial DNA variability within Māori populations suggest New Zealand was first settled by Eastern Polynesians between 1250 and 1300, concluding a long series of voyages through the southern Pacific islands.
Over the centuries that followed, these settlers developed a distinct culture now known as Māori. The population was divided into iwi and hapū who would sometimes cooperate, sometimes compete and sometimes fight against each other. At some point a group of Māori migrated to Rēkohu, now known as the Chatham Islands, where they developed their distinct Moriori culture; the Moriori population was all but wiped out between 1835 and 1862 because of Taranaki Māori invasion and enslavement in the 1830s, although European diseases contributed. In 1862 only 101 survived, the last known full-blooded Moriori died in 1933; the first Europeans known to have reached New Zeala
A swamp is a wetland, forested. Many swamps occur along large rivers where they are critically dependent upon natural water level fluctuations. Other swamps occur on the shores of large lakes; some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundation or soil saturation. The two main types of swamp swamp forests and "transitional" or shrub swamps. In the boreal regions of Canada, the word swamp is colloquially used for what is more termed a bog, fen, or muskeg; the water of a swamp may be brackish water or seawater. Some of the world's largest swamps are found along major rivers such as the Amazon, the Mississippi, the Congo. A marsh is a wetland composed of grasses and reeds found near the fringes of lakes and streams, serving as a transitional area between land and aquatic ecosystems. A swamp is a wetland composed of shrubs found along large rivers and lake shores. Swamps are characterized by slow-moving to stagnant waters.
Many adjoin rivers or lakes. Swamps are features of areas with low topographic relief. Humans have drained swamps to provide additional land for agriculture and to reduce the threat of diseases borne by swamp insects and similar animals. Many swamps have undergone intensive logging, requiring the construction of drainage ditches and canals; these ditches and canals contributed to drainage and, along the coast, allowed salt water to intrude, converting swamps to marsh or to open water. Large areas of swamp were therefore degraded. Louisiana provides a classic example of wetland loss from these combined factors. Europe has lost nearly half its wetlands. New Zealand lost 90 percent of its wetlands over a period of 150 years. Ecologists recognise that swamps provide valuable ecological services including flood control, fish production, water purification, carbon storage, wildlife habitat. In many parts of the world authorities protect swamps. In parts of Europe and North America, swamp restoration projects are becoming widespread.
The simplest steps to restoring swamps involve plugging drainage ditches and removing levees. Swamps and other wetlands have traditionally held a low property value compared to fields, prairies, or woodlands, they have a reputation for being unproductive land that cannot be utilized for human activities, other than hunting and trapping. Farmers, for example drained swamps next to their fields so as to gain more land usable for planting crops. Many societies now realize that swamps are critically important to providing fresh water and oxygen to all life, that they are breeding grounds for a wide variety of species. Indeed, floodplain swamps are important in fish production. Government environmental agencies are taking steps to protect and preserve swamps and other wetlands. In Europe, major effort is being invested in the restoration of swamp forests along rivers. Conservationists work to preserve swamps such as those in northwest Indiana in the United States Midwest that were preserved as part of the Indiana Dunes.
The problem of invasive species has been put into greater light such as in places like the Everglades. Swamps can be found on all continents except Antarctica; the largest swamp in the world is the Amazon River floodplain, significant for its large number of fish and tree species. The Sudd and the Okavango Delta are Africa's best known marshland areas; the Bangweulu Floodplains make up Africa's largest swamp. The Tigris-Euphrates river system is a large swamp and river system in southern Iraq, traditionally inhabited in part by the Marsh Arabs. In Asia, tropical peat swamps are located in mainland East Southeast Asia. In Southeast Asia, peatlands are found in low altitude coastal and sub-coastal areas and extend inland for distance more than 100 km along river valleys and across watersheds, they are to be found on the coasts of East Sumatra, West Papua, Papua New Guinea, Peninsular Malaya, Sarawak, Southeast Thailand, the Philippines. Indonesia has the largest area of tropical peatland. Of the total 440,000 km2 tropical peat swamp, about 210,000 km2 are located in Indonesia.
The Vasyugan Swamp is a large swamp in the western Siberia area of the Russian Federation. This is one of the largest swamps in the world; the Atchafalaya Swamp at the lower end of the Mississippi River is the largest swamp in the United States. It is an important example of southern cypress swamp but it has been altered by logging and levee construction. Other famous swamps in the United States are the forested portions of the Everglades, Okefenokee Swamp, Barley Barber Swamp, Great Cypress Swamp and the Great Dismal Swamp; the Okefenokee is located in extreme southeastern Georgia and extends into northeastern Florida. The Great Cypress Swamp is in Delaware but extends into Maryland on the Delmarva Peninsula. Point Lookout State Park on the southern tip of Maryland contains a large amount of swamps and marshes; the Great Dismal Swamp lies in extreme southeastern Virginia and extreme northeastern North Carolina. Both are National Wildlife Refuges. Another swamp area, Reelfoot Lake of extreme western Tennessee and Kentucky, was created by the 1811–12 New Madrid earthquakes.
Caddo Lake, the Great Dismal and Reelfoot are swamps. Swamps are called bayous in the southeastern United States in the Gulf Coast region; the worl
The ivory-billed woodpecker is one of the largest woodpeckers in the world, at 20 inches long and 30 inches in wingspan. It is native to types of virgin forest ecosystems found in the Southeastern United States and Cuba. Habitat destruction and, to a lesser extent, hunting have decimated populations so that the species is probably extinct, though sporadic reports of sightings have continued into the 21st century; the ivory-billed woodpecker, dubbed the "holy grail bird" due to its appearance and behavior, is the subject of many rediscovery efforts and much speculation. The species is listed as critically endangered by the International Union for Conservation of Nature; the American Birding Association lists the ivory-billed woodpecker as a class 6 species, a category it defines as "definitely or extinct". Reports of at least one male ivory-billed woodpecker in Arkansas in 2004 were investigated and subsequently published in April 2005 by a team led by the Cornell Lab of Ornithology. No definitive confirmation of those reports emerged, despite intensive searching over five years following the initial sightings.
An anonymous $10,000 reward was offered in June 2006 for information leading to the discovery of an ivory-billed woodpecker nest, roost, or feeding site. In December 2008, the Nature Conservancy announced a reward of $50,000 to the person who can lead a project biologist to a living ivory-billed woodpecker. In late September 2006, a team of ornithologists from Auburn University and the University of Windsor published reports of their own sightings of ivory-billed woodpeckers along the Choctawhatchee River in northwest Florida, beginning in 2005; these reports were accompanied by evidence that the authors themselves considered suggestive for the existence of ivory-billed woodpeckers. Searches in this area of Florida through 2009 failed to produce definitive confirmation. In January 2017, a scientist at the Naval Research Laboratory published a report of 10 sightings of ivory-billed woodpeckers, including nine in the Pearl River along the Louisiana-Mississippi border and one in the Choctawhatchee River.
Three of the claimed sightings are shown in video footage of birds with flights, field marks, other characteristics that the author claims are not consistent with any species of the region other than the ivory-billed woodpecker. Nobody has managed to obtain indisputable photographic evidence for the persistence of the ivory-billed woodpecker, but the paper contains an analysis based on factors related to behavior and habitat suggesting that such evidence is unlikely to be obtained in time to make a difference in the conservation of this species; the identification has been received with skepticism. Despite published reports from Arkansas and Louisiana, sporadic reports elsewhere in the historic range of the species since the 1940s, no universally accepted evidence exists for the continued existence of the ivory-billed woodpecker. Land acquisition and habitat restoration efforts have been initiated in certain areas where a high probability exists that the species might survive to protect any possible surviving individuals.
Ivory-billed woodpecker is the common name of several species of woodpecker distinguished by having a bill that resembles ivory: Campephilus is a genus of woodpecker sometimes called the ivory-billed woodpecker, although the term is more used to describe the American and Cuban ivory-billed woodpeckers. Cuban ivory-billed woodpecker, is now believed to be extinct. American ivory-billed woodpecker, is described here; the ivory-billed woodpecker is the type species for the genus Campephilus, a group of large American woodpeckers. Although they look similar to the pileated woodpeckers, they are not close relatives as the pileated is a member of the genus Dryocopus. Ornithologists have traditionally recognized two subspecies of this bird: the American ivory-billed, the more famous of the two, the Cuban ivory-billed woodpecker; the two look similar despite differences in plumage. Some controversy exists over whether the Cuban ivory-billed woodpecker is more appropriately recognized as a separate species.
A recent study compared DNA samples taken from specimens of both ivory-billed birds along with the imperial woodpecker, a larger but otherwise similar bird. It concluded not only that the Cuban and American ivory-billed woodpeckers are genetically distinct, but that they and the imperial form a North American clade within Campephilus that appeared in the mid-Pleistocene; the study does not attempt to define a lineage linking the three birds, though it does imply that the Cuban bird is more related to the imperial. The American Ornithologists' Union Committee on Classification and Nomenclature has said it is not yet ready to list the American and Cuban as separate species. Lovette, a member of the committee, said that more testing is needed to support that change, but concluded, "These results will initiate an interesting debate on how we should classify these birds."While recent evidence suggesting that American ivory-billed woodpeckers still exist in the wild has caused excitement in the ornithology community, no similar evidence exists for the Cuban ivory-billed bird, believed to be extinct since the last sighting in the late 1980s.
The ivory-billed woodpecker was the largest woodpecker in the United States. The related and probably extinct imperial woodpecker of western Mexico is, or was, the largest woodpecker. The
Bycatch, in the fishing industry, is a fish or other marine species, caught unintentionally while catching certain target species and target sizes of fish, crabs etc. Bycatch is either of a different species, the wrong sex, or is undersized or juvenile individuals of the target species; the term "bycatch" is sometimes used for untargeted catch in other forms of animal harvesting or collecting. In 1997, the Organisation for Economic Co-operation and Development defined bycatch as "total fishing mortality, excluding that accounted directly by the retained catch of target species". Bycatch is a mechanism of overfishing for unintentional catch; the average annual bycatch rate of pinnipeds and cetaceans in the U. S. from 1990 to 1999 was estimated at 6215 animals with a standard error of 448. The fisherman bycatch issue originated due to the "mortality of dolphins in tuna nets in the 1960s". There are at least four different ways the word "bycatch" is used in fisheries: Catch, retained and sold but, not the target species for the fishery Species/sizes/sexes of fish which fishermen discard Non-target fish, whether retained and sold or discarded Unwanted invertebrate species, such as echinoderms and non-commercial crustaceans, various vulnerable species groups, including seabirds, sea turtles, marine mammals and elasmobranchs.
Additionally, the term "deliberate bycatch" is used to refer to bycatch as a source of illegal wildlife trade in several areas throughout world. Given the popularity of recreational fishing throughout the world, a small local study in the US in 2013 suggested that discards may be an important unmonitored source of fish mortality; the highest rates of incidental catch of non-target species are associated with tropical shrimp trawling. In 1997, the Food and Agriculture Organization of the United Nations documented the estimated bycatch and discard levels from shrimp fisheries around the world, they found discard rates as high as 20:1 with a world average of 5.7:1. Shrimp trawl fisheries catch 2% of the world total catch of all fish by weight, but produce more than one-third of the world total bycatch. American shrimp trawlers produce bycatch ratios between 3:1 and 15:1. Trawl nets in general, shrimp trawls in particular, have been identified as sources of mortality for cetacean and finfish species.
When bycatch is discarded, it is dead or dying. Tropical shrimp trawlers make trips of several months without coming to port. A typical haul may last 4 hours. Just before it is pulled on board the net is washed by zigzagging at full speed; the contents are dumped on deck and are sorted. An average of 5.7:1 means. In tropical inshore waters the bycatch consists of small fish; the shrimps are stored on-board. Recent sampling in the South Atlantic rock shrimp fishery found 166 species of finfish, 37 crustacean species, 29 other species of invertebrate among the bycatch in the trawls. Another sampling of the same fishery over a two-year period found that rock shrimp amounted to only 10% of total catch weight. Iridescent swimming crab, dusky flounder, inshore lizardfish, brown shrimp, longspine swimming crabs, other bycatch made up the rest. Despite the use of bycatch reduction devices, the shrimp fishery in the Gulf of Mexico removes about 25–45 million red snapper annually as bycatch, nearly one half the amount taken in directed recreational and commercial snapper fisheries.
Cetaceans, such as dolphins and whales, can be affected by entanglement in fishing nets and lines, or direct capture by hooks or in trawl nets. Cetacean bycatch is increasing in frequency. In some fisheries, cetaceans are captured as bycatch but retained because of their value as food or bait. In this fashion, cetaceans can become a target of fisheries. One example of bycatch is dolphins caught in tuna nets; as dolphins are mammals and do not have gills they may drown. This bycatch issue has been one of the reasons of the growing ecolabelling industry, where fish producers mark their packagings with disclaimers such as "dolphin friendly" to reassure buyers. However, "dolphin friendly" does not mean that dolphins were not killed in the production of a particular tin of tuna, but that the fleet which caught the tuna did not target a feeding pod of dolphins, but relied on other methods to spot tuna schools; the by-catch of the Caspian Seal may be recognized as the one of the biggest entanglements of pinnipeds as by-catch in the world Of the 21 albatross species recognised by IUCN on their Red List, 19 are threatened, the other two are near threatened.
Two species are considered critically endangered: the Amsterdam albatross and the Chatham albatross. One of the main threats is commercial long-line fishing, because the albatrosses and other seabirds which feed on offal are attracted to the set bait, after which they become hooked on the lines and drown. An estimated 100,000 albatross per year are killed in this fashion. Unregulated pirate fisheries exacerbate the problem. Sea turtles critically endangered, have been killed in large numbers in shrimp trawl nets. Estimates indicate that thousands of Kemp's ridley, loggerhead and leatherback sea turtles are caught in shrimp trawl fisheries in the Gulf of Mexico and the US Atlantic annually The speed and length of the trawl method is significant because, “for a tow duration of less than 10 minutes, the mortality rate for sea turtles is less than one percent, whereas for tows greater than six