HOME

TheInfoList



OR:

The American avocet (''Recurvirostra americana'') is a large
wader 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
in the
avocet The four species of avocets are a genus, ''Recurvirostra'', of waders in the same avian family as the stilts. The genus name comes from Latin , 'curved backwards' and , 'bill'. The common name is thought to derive from the Italian ( Ferrarese) w ...
and
stilt Stilt is a common name for several species of birds in the family Recurvirostridae, which also includes those known as avocets. They are found in brackish or saline wetlands in warm or hot climates. They have extremely long legs, hence the grou ...
family,
Recurvirostridae The Recurvirostridae are a family of birds in the wader suborder Charadrii. It contains two distinct groups of birds, the avocets (one genus) and the stilts (two genera). Description Avocets and stilts range in length from and in weight fro ...
, that is found in North America. It spends much of its time foraging in shallow water or on mud flats, often sweeping its bill from side to side in water as it seeks its
crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...
and
insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...
prey.


Taxonomy

The American avocet was formally described in 1789 by the German naturalist
Johann Friedrich Gmelin , fields = , workplaces = University of GöttingenUniversity of Tübingen , alma_mater = University of Tübingen , doctoral_advisor = Philipp Friedrich GmelinFerdinand Christoph Oetinger , academic_advisors = , doctora ...
in his revised and expanded edition of
Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...
's ''
Systema Naturae ' (originally in Latin written ' with the ligature æ) is one of the major works of the Swedish botanist, zoologist and physician Carl Linnaeus (1707–1778) and introduced the Linnaean taxonomy. Although the system, now known as binomial nomen ...
''. He placed it with the
pied avocet The pied avocet (''Recurvirostra avosetta'') is a large black and white wader in the avocet and stilt family, Recurvirostridae. They breed in temperate Europe and across the Palearctic to Central Asia then on to the Russian Far East. It is a mig ...
in the
genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
''
Recurvirostra The four species of avocets are a genus, ''Recurvirostra'', of waders in the same avian family as the stilts. The genus name comes from Latin , 'curved backwards' and , 'bill'. The common name is thought to derive from the Italian ( Ferrarese) ...
'' and coined the
binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
''Recurvirostra americana''. Gmelin based his description on that by the English ornithologist John Latham who in 1785 had described and illustrated the American avocet in his ''A General Synopsis of Birds''. Latham cited the earlier publication by
William Dampier William Dampier (baptised 5 September 1651; died March 1715) was an English explorer, pirate, privateer, navigator, and naturalist who became the first Englishman to explore parts of what is today Australia, and the first person to circumnav ...
and also that by
Thomas Pennant Thomas Pennant (14 June Old Style, OS 172616 December 1798) was a Welsh natural history, naturalist, traveller, writer and antiquarian. He was born and lived his whole life at his family estate, Downing Hall near Whitford, Flintshire, in Wales ...
. The genus name combines the
Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...
meaning 'bent' or 'curved backwards' with meaning 'bill'. The species is
monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...
: no
subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...
are recognised. The American avocet is a member of the order
Charadriiformes Charadriiformes (, from ''Charadrius'', the type genus of family Charadriidae) is a diverse order of small to medium-large birds. It includes about 390 species and has members in all parts of the world. Most charadriiform birds live near water an ...
, which includes shorebirds, gulls, and alcids. Its family,
Recurvirostridae The Recurvirostridae are a family of birds in the wader suborder Charadrii. It contains two distinct groups of birds, the avocets (one genus) and the stilts (two genera). Description Avocets and stilts range in length from and in weight fro ...
, includes stilts and avocets. The genus ''Recurvirostra'' includes three other species: the
Andean avocet The Andean avocet (''Recurvirostra andina'') is a large wader in the avocet and stilt bird family, Recurvirostridae. It is resident in the Andes, breeding above 3500 m in northwestern Argentina, western Bolivia, northern Chile and southern Peru ...
, the
pied avocet The pied avocet (''Recurvirostra avosetta'') is a large black and white wader in the avocet and stilt family, Recurvirostridae. They breed in temperate Europe and across the Palearctic to Central Asia then on to the Russian Far East. It is a mig ...
, and the
red-necked avocet The red-necked avocet (''Recurvirostra novaehollandiae'') also known as the Australian avocet, cobbler, cobbler's awl, and painted lady, is a wader of the family Recurvirostridae that is endemic to Australia and is fairly common and widespread th ...
.


Description

The American avocet measures in length, has a wingspan of and weighs The bill is black, pointed, and curved slightly upwards towards the tip. It is long, surpassing twice the length of the avocet's small, rounded head. Like many
wader 245px, A flock of Dunlins and Red knots">Red_knot.html" ;"title="Dunlins and Red knot">Dunlins and Red knots Waders or shorebirds are birds of the order Charadriiformes commonly found wikt:wade#Etymology 1, wading along shorelines and mudflat ...
s, the avocet has long, slender legs and slightly webbed feet. The legs are a pastel grey-blue, giving it its colloquial name, blue shanks. The plumage is black and white on the back, with white on the underbelly. During the breeding season, the plumage is brassy orange on the head and neck, continuing somewhat down to the breast. After the breeding season, these bright feathers are swapped out for white and grey ones. The avocet commonly preens its feathers - this is considered to be a comfort movement. The call has been described as both a shrill and melodic alarm , which rises in inflection over time. Avocets use three distinct calls: common call, excited call, and broken wing call. The common call is a loud repeated . The excited call has a similar sound, but it speeds up rather than having an even rhythm. Lastly, the broken wing call is noticeably different from the other two calls. It is a distressed screech sound and is alarming rather than melodic.


Distribution and habitat

American avocets were previously found across most of the United States until
extirpated Local extinction, also known as extirpation, refers to a species (or other taxon) of plant or animal that ceases to exist in a chosen geographic area of study, though it still exists elsewhere. Local extinctions are contrasted with global extinct ...
from the East Coast. The breeding habitat consists of marshes, beaches, prairie ponds, and shallow lakes in the mid-west, as far north as southern Canada. These breeding grounds are largely in areas just east of the rocky mountains including parts of Alberta, Saskatchewan, Montana, Idaho, Washington, Utah, North and South Dakota, Nebraska, Colorado, and even down to parts of New Mexico, Oklahoma and Texas. Their
migration Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...
route lands them in almost every state in the western United States. The avocet's wintering grounds are mainly coastal. Along the Atlantic Ocean, they are found in North and South Carolina, Georgia and Florida. There are also wintering grounds along the Gulf of Mexico in Florida, Texas, and Mexico, and along the Pacific Ocean in California and Mexico. There are resident populations in the Mexican States of Zacatecas, San Luis Potosí, Guanajuato, Hidalgo, Mexico City and Puebla, and in Central California. Flocks ranging from 50 to 300 avocets migrate together to their breeding sites together during peak season, which is typically in the spring.


Behavior and ecology


Breeding

The American avocet breeds in anything from freshwater to
hypersaline A hypersaline lake is a landlocked body of water that contains significant concentrations of sodium chloride, brines, and other salts, with saline levels surpassing that of ocean water (3.5%, i.e. ). Specific microbial species can thrive in h ...
wetlands in the western and mid-west United States. After reaching their breeding grounds, the avocets quickly establish territory in pairs. Throughout the breeding season, these pairs engage in a series of
copulatory Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
displays, which is initiated by either sex and often involves preening. After breeding, the birds gather in large flocks, sometimes amounting to hundreds of birds. Nesting takes place near water, often alongside black-necked stilts, usually on small islands or mucky shorelines. The avocets nest on the ground in places with little to no surrounding vegetation. They make shallow indentations in the ground for their nest and line it with grass, feathers, pebbles or other small objects. Some avocets do not line their nests at all. During the breeding season, avocets lay around 3–5 eggs, with 4 being the most common number. One case study of the 1968 and 1969 breeding seasons suggests that this number allows for the highest rate of hatching success. They incubate them over a period of 23–25 days. Both parents are involved in the incubation process, taking turns during the day (except at night, where only the female incubates the eggs). Both parents take care of the newborn American avocets after they hatch. Male parents are more present in incubation during the first 8 days, whereas female parents dominate incubation throughout the remaining 16 days. Time spent caring for newborn chicks equates to that spent incubating. Since newborns are able to walk, they are capable of feeding themselves and do not require extensive care from their parents. The young are expected to begin flying 4 to 5 weeks after hatching.


Anti-predator behavior

Each pair defends their own territory against predators and other avocets. Nests are built in areas that predators would struggle to gain access to. Predators that do try to approach the colony find themselves surrounded by several adult avocets running around, trying to distract them. While incubating however, the avocets tend only to their nest and defense is considered a lower priority, unless the eggs are in immediate danger, in which case the avocets may take more aggressive measures, calling loudly and flying at the threat.


Food and feeding

The American avocet tends to prefer habitats with fine sediments for foraging. In the winter, it feeds extensively on brine shrimp. Usually, this entails the avocet pecking while walking or wading on the shore, but it can also swim to expand foraging area. During the breeding season, avocets continue to eat brine shrimp but switch mainly to consuming brine flies. Brine flies and brine fly larvae are so abundant in avocet breeding grounds that they often blacken the surface of any exposed mud. Brine flies sustain the avocet during its breeding season. The avocet employs both visual and tactile methods of feeding. The primary visual feeding method is pecking at flies. However the avocet will also feed by plunging (wherein the head and neck of the bird are submerged), snatching (wherein the bird catches a flying insect), and bill pursuit (wherein the bird repeatedly opens and closes its bill while moving its head along the surface of the water). Methods of tactile feeding include filtering, scraping, and scythe feeding.


Threats and conservation status

Shooting and trapping of American avocets led to population decline until the 1900s. During this time, the species was extirpated from most of the East Coast of the United States. By 1918, Avocets became protected under the
Migratory Bird Treaty Act The Migratory Bird Treaty Act of 1918 (MBTA), codified at (although §709 is omitted), is a United States federal law, first enacted in 1918 to implement the convention for the protection of migratory birds between the United States and Canada . ...
(16 U.S.C. 703-712). Since that time, other threats have emerged. Contaminants and toxins such as
DDT Dichlorodiphenyltrichloroethane, commonly known as DDT, is a colorless, tasteless, and almost odorless crystalline chemical compound, an organochloride. Originally developed as an insecticide, it became infamous for its environmental impacts. ...
,
selenium Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
, and
methylmercury Methylmercury (sometimes methyl mercury) is an organometallic cation with the formula . It is the simplest organomercury compound. Methylmercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It is a ...
, have increased in American Avocet habitats in recent years. Although the effects are highly contested, these increased concentrations have potential negative effects on American avocet breeding success, especially because Avocet chicks are more susceptible to environmental disruptions than adults. The avocet also faces habitat loss. While agricultural and industrial environments have become alternate habitat for the avocet, natural wetlands are decreasing rapidly. Additionally, increases in the salinity levels of wetlands have had adverse effects on the breeding and development of avocets. Young avocets in saline or hypersaline environments often combat weight loss and dehydration. Although American avocets face numerous environmental challenges, numbers have stayed steady, and according to the National Audubon Society, numbers have been increasing steadily in the eastern United States for the past few years. The American avocet is protected under the
Migratory Bird Treaty Act of 1918 The Migratory Bird Treaty Act of 1918 (MBTA), codified at (although §709 is omitted), is a United States federal law, first enacted in 1918 to implement the convention for the protection of migratory birds between the United States and Canada . ...
.Migratory Bird Treaty
/ref>


In culture

In his famous ''
The Birds of America ''The Birds of America'' is a book by naturalist and painter John James Audubon, containing illustrations of a wide variety of birds of the United States. It was first published as a series in sections between 1827 and 1838, in Edinburgh and ...
'',
John James Audubon John James Audubon (born Jean-Jacques Rabin; April 26, 1785 – January 27, 1851) was an American self-trained artist, naturalist, and ornithologist. His combined interests in art and ornithology turned into a plan to make a complete pictoria ...
describes a day of stalking and spying on the avocet. He judiciously noted their foraging, nesting, defensive, and flight behaviors.


Gallery

American Avocet winter plumage.jpg, Winter plumage Nesting American Avocet.jpg, Nesting Recurvirostra americana -Palo Alto Baylands -chick-8b.jpg, Adult with a chick at
Palo Alto Baylands Nature Preserve The Palo Alto Baylands Nature Preserve, known officially as the Baylands Nature Preserve, is the largest tract of undisturbed marshland remaining in the San Francisco Bay. Fifteen miles of multi-use trails provide access to a unique mixture of t ...
, California Recurvirostra americana -Palo Alto Baylands-8.jpg, Breeding plumage Dan pancamo American Avocet 2.jpg, Quintana, Texas. Winter American avocet at Sacramento National Wildlife Refuge-5380.jpg, In flight at the
Sacramento National Wildlife Refuge The Sacramento National Wildlife Refuge Complex is part of the United States system of National Wildlife Refuges (NWR). It is located in northern California, in the valley of the Sacramento River. The Sacramento NWR Complex was created in an att ...
, California


References


External links


American avocet - ''Recurvirostra americana''
- USGS Patuxent Bird Identification InfoCenter

– Cornell Lab of Ornithology * * * {{Taxonbar, from=Q469992
American avocet The American avocet (''Recurvirostra americana'') is a large wader in the avocet and stilt family, Recurvirostridae, that is found in North America. It spends much of its time foraging in shallow water or on mud flats, often sweeping its bill ...
Native birds of the Canadian Prairies Birds of the United States Native birds of the Western United States Birds of Mexico
American avocet The American avocet (''Recurvirostra americana'') is a large wader in the avocet and stilt family, Recurvirostridae, that is found in North America. It spends much of its time foraging in shallow water or on mud flats, often sweeping its bill ...
American avocet The American avocet (''Recurvirostra americana'') is a large wader in the avocet and stilt family, Recurvirostridae, that is found in North America. It spends much of its time foraging in shallow water or on mud flats, often sweeping its bill ...