Black-necked stilt

Last updated

Contents

Black-necked stilt
Black-necked Stilt (Himantopus mexicanus), Corte Madera.jpg
Adult near Corte Madera, California
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Charadriiformes
Family: Recurvirostridae
Genus: Himantopus
Species:
H. mexicanus
Binomial name
Himantopus mexicanus
(P.L.S.Müller, 1776)
(but see text)
Himantopus mexicanus map.svg
Range of black-necked stilt (including white-backed stilt of most of South America, see text)
Synonyms

Himantopus himantopus mexicanus(Müller, 1776)
but see text

The black-necked stilt (Himantopus mexicanus) is a locally abundant shorebird of American wetlands and coastlines. It is found from the coastal areas of California through much of the interior western United States and along the Gulf of Mexico as far east as Florida, then south through Central America and the Caribbean to Brazil, Peru and the Galápagos Islands, with an isolated population, the Hawaiian stilt, in Hawaii. The northernmost populations, particularly those from inland, are migratory, wintering from the extreme south of the United States to southern Mexico, rarely as far south as Costa Rica; on the Baja California peninsula it is only found regularly in winter. [1] Some authorities, including the IUCN, treat it as a synonym of Himantopus himantopus . [2]

Taxonomy

Black-necked stilt of Quintana, Texas Black-necked Stilt of Quintana Texas1.jpg
Black-necked stilt of Quintana, Texas

It is often treated as a subspecies of the common or black-winged stilt, using the trinomial name Himantopus himantopus mexicanus. [3] However, the AOS has always considered it a species in its own right, and the scientific name Himantopus mexicanus is often seen. Matters are more complicated though; sometimes all five distinct lineages of the common stilt are treated as different species. The white-backed stilt from much of South America (H. melanurus when the species is recognized) is parapatric and intergrade to some extent with its northern relative where their ranges meet in northern Brazil and central Peru, would warrant inclusion with the black-necked stilt when this is separated specifically, becoming Himantopus mexicanus melanurus. Similarly, the Hawaiian stilt, H. m. knudseni, belongs to the (North) American species when this is considered separate; while it rarely has been treated as another distinct species, the AOS, BirdLife International and the IUCN do not.

Description

Flying in California, USA Himantopus mexicanus -Morro Bay, California, USA -flying-8.jpg
Flying in California, USA

Measurements: [4]

They have long pink legs and a long thin black bill. They are white below and have black wings and backs. The tail is white with some grey banding. A continuous area of black extends from the back along the hind neck to the head. There, it forms a cap covering the entire head from the top to just below eye-level, with the exception of the areas surrounding the bill and a small white spot above the eye. Males have a greenish gloss to the back and wings, particularly in the breeding season. This is less pronounced or absent in females, which have a brown tinge to these areas instead. Otherwise, the sexes look alike. [5]

Downy young are light olive brown with lengthwise rows of black speckles (larger on the back) on the upperparts essentially where adults are black and dull white elsewhere, with some dark barring on the flanks. [5]

Where their ranges meet in northern Brazil and central Peru, the black-necked and white-backed stilts intergrade. Such individuals often have some white or grey on top of the head and a white or grey collar separating the black of the hindneck from that of the upper back.

The black-necked stilt is distinguished from non-breeding vagrants of the black-winged stilt by the white spot above the eye. Vagrants of the northern American form in turn are hard to tell apart from the resident Hawaiian stilt, in which only the eye-spot is markedly smaller. But though many stilt populations are long-distance migrants and during their movements can be found hundreds of miles offshore, [6] actual trans-oceanic vagrants are nonetheless a rare occurrence. [5]

Distribution and habitat

The black-necked stilt is found in estuarine, lacustrine, salt pond and emergent wetland habitats; it is generally a lowland bird but in Central America has been found up to 8,200 ft (2,500 m) ASL and commonly seen in llanos habitat in northern South America. [5] It is also found in seasonally flooded wetlands. Use of salt evaporation ponds has increased significantly since 1960 in the US, and they may now be the primary wintering habitat; these salt ponds are especially prevalent in southern San Francisco Bay. At the Salton Sea, the black-necked stilt is resident year-round. [7]

This bird is locally abundant in the San Joaquin Valley, where it commonly winters. [8] It is common to locally abundant in appropriate habitat in southern California from April to September. [7]

It also breeds along lake shores in northeastern California and southeastern Oregon as well as along the Colorado River. In North America outside California, the black-necked stilt rarely breeds inland, but it is known as a breeding bird in riparian locales in Arizona [9] and elsewhere in the southern USA. In Arizona, black-necked stilts may be seen along artificially created lakes and drainage basins in the Phoenix metropolitan area, in remnant riparian habitat.

For flocks that summer in the northern Central Valley of California, a migration occurs to the San Joaquin Valley to consolidate with flocks that were already summering there. In coastal areas flocks both summer and winter in these estuarine settings.

Fall migration of the northernly birds takes place from July to September, and they return to the breeding grounds between March and May. Usually, the entire population breeding at any one site arrives, mates, incubates eggs for about a month, and protects and broods the young until they are capable of sustained flight (at 27–31 days old) and leaves again migrating in flocks of about 15 individuals sometimes juveniles congregating in small groups and other times siblings with family groups. [10] [11] There is some seasonal movement of the tropical populations, but this is not long-range and poorly understood. [5]

The parasitic cyclocoeline flatworm Neoallopyge americanensis was described from the air sacs of a black-necked stilt from Texas. Its genus is presently monotypic and seems to be closely related to the similar genus Allopyge , found in Old World cranes. [12]

Food and feeding

Black-necked stilts foraging on Richardson Bay mudflats Bnstiltpair.jpg
Black-necked stilts foraging on Richardson Bay mudflats

The black-necked stilt forages by probing and gleaning primarily in mudflats and lakeshores, but also in very shallow waters near shores; it seeks out a range of aquatic invertebrates mainly crustaceans (such as shrimp) [13] and other arthropods (such as worms and flies), [13] and mollusks and small fish, tadpoles and very rarely plant seeds. Its mainstay food varies according to availability; inland birds usually feed mainly on aquatic insects and their larvae, while coastal populations mostly eat other aquatic invertebrates. For feeding areas they prefer coastal estuaries, salt ponds, lakeshores, alkali flats and even flooded fields. [7] For roosting and resting needs, this bird selects alkali flats (even flooded ones), lake shores, and islands surrounded by shallow water. [5]

Breeding

Black-necked stilt eggs Quintana, Texas Black-necked Stilt Eggs1.jpg
Black-necked stilt eggs Quintana, Texas

This stilt chooses mudflats, desiccated lacustrine verges, and levees for nest locations, as long as the soil is friable. Reproduction occurs from late April through August in North America, with peak activity in June, [14] while tropical populations usually breed after the rainy season. The nests are typically sited within 1 km (0.62 mi) of a feeding location, and the pairs defend an extensive perimeter around groups of nests, patrolling in cooperation with their neighbors. [15] Spacing between nests is approximately 65 ft (20 m), but sometimes nests are within 7 ft (2.1 m) of each other and some nests in the rookery are as far as 130 ft (40 m) from the nearest neighbor. The black-necked stilt is actually classified as semicolonial since the nests are rarely found alone and colonies usually number dozens, rarely hundreds of pairs. [16] The nests are frequently established rather close to the water edge, so that their integrity is affected by rising water levels of ponds or tides. This is particularly a hazard in the case of managed salt ponds where water levels may be altered rapidly in the salt pond flooding process. [5] [17]

The clutch size generally is 3–5 eggs with an average of four. For 22–26 days both sexes take turns incubating the eggs. The young are so precocial that they are seen swimming within two hours after hatching [18] and are also capable of rapid land velocity at that early time. In spite of this early development the young normally return to the nest for resting for one or two more days. They fledge after about one month but remain dependent on their parents for some more weeks. Birds begin to breed at 1–2 years of age. [5]

Status

Particularly the North American populations of the black-necked stilt have somewhat declined in the 20th century, mainly due to conversion of habitat for human use and pollution affecting both the birds directly as well as their food stocks. But altogether, the population is healthy and occurs over a large range. This stilt is therefore classified as a Species of Least Concern by the IUCN. [2] The Hawaiian stilt, which on occasionally has been separated as a distinct species, is very rare however and numbers less than 2,000 individuals. [5] Predation by the small Indian mongoose (Urva auropunctata), introduced to hunt rats, is suspected to have contributed to its decline. [19]

Notes

  1. Pierce (1996), Sibley (2003)
  2. 1 2 BirdLife International (2019) [amended version of 2016 assessment]. "Himantopus himantopus". IUCN Red List of Threatened Species . 2019: e.T22727969A155440465. doi: 10.2305/IUCN.UK.2019-3.RLTS.T22727969A155440465.en . Retrieved 9 December 2023.
  3. E.g. Pierce (1996)
  4. "Black-necked Stilt Identification, All About Birds, Cornell Lab of Ornithology". www.allaboutbirds.org. Retrieved 2020-09-30.
  5. 1 2 3 4 5 6 7 8 9 Pierce (1996)
  6. E.g. as a casual visitor on Clarión in the Revillagigedo Islands: Brattstrom & Howell (1953)
  7. 1 2 3 Garrett & Dunn (1981)
  8. McCaskie et al. (1979)
  9. Corman & Wise-Gervais (2005)
  10. Robinson, Julie A., J. Michael Reed, Joseph P. Skorupa and Lewis W. Oring. 1999. "Black-necked Stilt (Himantopus mexicanus)", The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from The Birds of North America Online: bna.birds.cornell.edu/bna/species/449
  11. Sordahl, T. A. 1980. Antipredator behavior and parental care in the American Avocet and Black-necked Stilt (Aves: Recurvirostridae). Ph.D. thesis. Utah State Univ. Logan.
  12. Dronen et al. (2006)
  13. 1 2 Himantopus mexicanus (Black-necked Stilt) The Online Guide to the Animals of Trinidad and Tobago. Retrieved 16 March 2023
  14. Bent (1927)
  15. Hamilton (1975)
  16. Zeiner et al. (1988)
  17. Rigney & Rigney (1981)
  18. Harrison (1978)
  19. Hays & Conant (2007)

Related Research Articles

<span class="mw-page-title-main">Stilt</span> Commons name for several species of bird

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.

<span class="mw-page-title-main">Recurvirostridae</span> Family of birds

The Recurvirostridae are a family of birds in the wader suborder Charadrii. It contains two distinct groups of birds, the avocets and the stilts.

<span class="mw-page-title-main">American avocet</span> Species of bird

The American avocet is a large wader in the avocet and stilt family, Recurvirostridae, 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 crustacean and insect prey.

<span class="mw-page-title-main">Black-winged stilt</span> Species of bird

The black-winged stilt is a widely distributed, very long-legged wader in the avocet and stilt family Recurvirostridae. Its scientific name, Himantopus himantopus, is sometimes used to generalize a single, almost cosmopolitan species. Alternatively, it is restricted to the form that is widespread in Europe, Asia and Africa, which equals the nominate group of H. himantopussensu lato. Meanwhile, the black-necked and white-backed stilts both inhabit the Americas; the pied stilt ranges from Australasia and New Zealand. Today, most sources accept between one and four actual species.

<span class="mw-page-title-main">Stilt sandpiper</span> Species of bird

The stilt sandpiper is a small shorebird. The scientific name is from Ancient Greek. The genus name kalidris or skalidris is a term used by Aristotle for some grey-coloured waterside birds. The specific himantopus means "strap foot" or "thong foot".

<span class="mw-page-title-main">California gull</span> Species of bird

The California gull is a medium-sized gull, smaller on average than the herring gull, but larger on average than the ring-billed gull. It lives not just in California, but up and down the entire Western coast of North America, and has breeding ground inland. The yellow bill has a black ring.

<span class="mw-page-title-main">Banded stilt</span> Species of Australian bird in the family Recurvirostridae

The banded stilt is a nomadic wader of the stilt and avocet family, Recurvirostridae, native to Australia. It belongs to the monotypic genus Cladorhynchus. It gets its name from the red-brown breast band found on breeding adults, though this is mottled or entirely absent in non-breeding adults and juveniles. Its remaining plumage is pied and the eyes are dark brown. Nestling banded stilts have white down, unlike any other species of wader.

<span class="mw-page-title-main">Black stilt</span> Species of bird

The black stilt or kakī (Māori) is a wading bird found in New Zealand. It is one of the world's rarest birds, with 169 adults surviving in the wild as of May 2020. Adult kakī have distinctive black plumage, long pink legs, and a long thin black bill. Black stilts largely breed in the Mackenzie Basin in the South Island, and are threatened by introduced feral cats, ferrets, and hedgehogs as well as habitat degradation from hydroelectric dams, agriculture, and invasive weeds.

Hybridisation in shorebirds has been proven on only a small number of occasions; however, many individual shorebirds have been recorded by birdwatchers worldwide that do not fit the characters of known species. Many of these have been suspected of being hybrids. In several cases, shorebird hybrids have been described as new species before their hybrid origin was discovered. Compared to other groups of birds, only a few species of shorebirds are known or suspected to hybridise, but nonetheless, these hybrids occur quite frequently in some cases.

<span class="mw-page-title-main">Red-necked avocet</span> Species of bird

The red-necked avocet 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 throughout, except for the north and north east coastal areas of the country. Closely related to the stilts, it shares their fragile slender elegance, however the deep red head and neck distinguish them. It appeared on a 13 cent postage stamp in 1966.

<span class="mw-page-title-main">Kealia Pond National Wildlife Refuge</span> Wildlife sanctuary in Maui, Hawaii, U.S.

Kealia Pond National Wildlife Refuge is a coastal salt marsh along the south-central coast of Maui, Hawaiʻi. The refuge is located between the towns of Kihei and Maalaea, on both sides of North Kihei Road, Route 31. The wetland is also a 691-acre (2.80 km2) bird sanctuary, home to 30 species of waterfowl, shorebirds, and migratory ducks, including the ʻaukuʻu and the endangered āeʻo and ʻalae keʻokeʻo. Kealia Pond was selected as a wildlife refuge in 1953, protecting an initial 300 acres (1.2 km2) of land. The refuge joined the National Wildlife Refuge System in 1992.

<span class="mw-page-title-main">Andean avocet</span> Species of bird

The Andean avocet 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.

<span class="mw-page-title-main">Pied stilt</span> Species of bird

The pied stilt, also known as the white-headed stilt, is a shorebird in the family Recurvirostridae. It is widely distributed with a large total population size and apparently stable population trend, occurring in Malaysia, Japan, the Philippines, Brunei, Christmas Island, Indonesia, Palau, Papua New Guinea, Australia, and New Zealand. It is listed as Least Concern on the IUCN Red List. It is sometimes considered a subspecies of the black-winged stilt.

<span class="mw-page-title-main">Hawaiian stilt</span> Subspecies of bird

The Hawaiian stilt is an endangered Hawaiian subspecies of the black-necked stilt species. It is a long-legged, slender shorebird with a long, thin beak. Other common names include the Hawaiian black-necked stilt, the aeʻo, the kukuluaeʻo, or it may be referred to as the Hawaiian subspecies of the black-necked stilt.

<span class="mw-page-title-main">White-backed stilt</span> Species of bird

The white-backed stilt is a locally abundant shorebird of South American wetlands and coastlines. It is found from northwest Brazil to southwest Peru and southcentral Argentina.

References

Further reading