Himantopus mexicanus knudseni - Stejneger, 1887
Hawaiian Stilt
Other English Common Names: Hawaiian stilt
Taxonomic Status: Accepted
Unique Identifier: ELEMENT_GLOBAL.2.100804
Element Code: ABNND01012
Informal Taxonomy: Animals, Vertebrates - Birds - Shorebirds
 
Kingdom Phylum Class Order Family Genus
Animalia Craniata Aves Charadriiformes Recurvirostridae Himantopus
Genus Size: B - Very small genus (2-5 species)
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Concept Reference
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Concept Reference: American Ornithologists' Union (AOU). 1957. The A.O.U. Check-list of North American Birds, 5th ed. Port City Press, Inc., Baltimore, MD. 691 pp.
Concept Reference Code: B57AOU01HQUS
Name Used in Concept Reference: Himantopus mexicanus knudseni
Taxonomic Comments: Has been treated as a distinct species, H. knudseni, as a subspecies of H. himantopus, and also under the names H. nigricollis and H. candidus.
Conservation Status
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NatureServe Status

Global Status: G5T2
Global Status Last Reviewed: 25Nov1996
Global Status Last Changed: 25Nov1996
Rounded Global Status: T2 - Imperiled
Reasons: Small range on several of the Hawaiian Islands; historical habitat has been drastically reduced; total population recently has been relatively stable at about 1200-1600 individuals; creation of wetland refuges has improved prospects for population persistence, but threats for further loss/degradation of habitat are developing; introduced predators are a problem.
Nation: United States
National Status: N2 (05Jan1997)

U.S. & Canada State/Province Status
Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
United States Hawaii (S2)

Other Statuses

U.S. Endangered Species Act (USESA): LE: Listed endangered (13Oct1970)
U.S. Fish & Wildlife Service Lead Region: R1 - Pacific

NatureServe Global Conservation Status Factors

Range Extent: 1000-20,000 square km (about 400-8000 square miles)
Range Extent Comments: Most (92%) of the population is on Maui, Oahu, and Kauai; annually present on Niihau, Molokai, and Hawaii; recently observed on Lanai (Engilis and Pratt 1993). Generally below elevation of 150 m (Matthews and Moseley 1990).

Number of Occurrences: 6 - 20
Number of Occurrences Comments: 137 occurrences, 112 current (1981-1996) and 25 historical (1954-1977). Number of distinct populations is far fewer than these numbers indicate.

Population Size: 1000 - 2500 individuals
Population Size Comments: Declined to about 300 in the 1940s. Counts from 1977 to 1983 yielded an average of about 900 individuals per count. Currently, the total population is probably between 1500 and 1800 birds and is relatively stable (though has steadily increased since 1982 on Oahu and Maui, due to active management) (Pratt et al. 1987, Engilis and Pratt 1993, Matthews and Moseley 1990, Morrison et al. 2001).

Overall Threat Impact Comments: Decline in past decades was due to loss of wetlands to dryland agriculture, commercial and residential development, and invasion by introduced plants; also negatively impacted by introduced predators. Current threats include introduced predators such as mongooses, rats, cats, and dogs, and loos/alteration of habitat (e.g., from coastal development). Future has become more secure with creation of wetland refuge system (Scott et al. 1988).

Short-term Trend: Relatively Stable (<=10% change)
Short-term Trend Comments: More or less stable in recent years. Current reproduction seems adequate for persistence.

Other NatureServe Conservation Status Information

Inventory Needs: Revisit sites with no stilt observations in the past five years to determine if the site is still active habitat.

Protection Needs: Acquire additional habitat. Protect remaining wetlands and rehabilitate degraded areas. Waterbird recovery plan recommends multiple sites on each island (USFWS 1985).

Distribution
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Global Range: (1000-20,000 square km (about 400-8000 square miles)) Most (92%) of the population is on Maui, Oahu, and Kauai; annually present on Niihau, Molokai, and Hawaii; recently observed on Lanai (Engilis and Pratt 1993). Generally below elevation of 150 m (Matthews and Moseley 1990).

U.S. States and Canadian Provinces

Due to latency between updates made in state, provincial or other NatureServe Network databases and when they appear on NatureServe Explorer, for state or provincial information you may wish to contact the data steward in your jurisdiction to obtain the most current data. Please refer to our Distribution Data Sources to find contact information for your jurisdiction.
Color legend for Distribution Map
NOTE: The maps for birds represent the breeding status by state and province. In some jurisdictions, the subnational statuses for common species have not been assessed and the status is shown as not-assessed (SNR). In some jurisdictions, the subnational status refers to the status as a non-breeder; these errors will be corrected in future versions of these maps. A species is not shown in a jurisdiction if it is not known to breed in the jurisdiction or if it occurs only accidentally or casually in the jurisdiction. Thus, the species may occur in a jurisdiction as a seasonal non-breeding resident or as a migratory transient but this will not be indicated on these maps. See other maps on this web site that depict the Western Hemisphere ranges of these species at all seasons of the year.
Endemism: endemic to a single state or province

U.S. & Canada State/Province Distribution
United States HI

Range Map
No map available.


U.S. Distribution by County Help
State County Name (FIPS Code)
HI Hawaii (15001), Honolulu (15003), Kauai (15007), Maui (15009)
* Extirpated/possibly extirpated
U.S. Distribution by Watershed Help
Watershed Region Help Watershed Name (Watershed Code)
20 Hawaii (20010000)+, Maui (20020000)+, Lanai (20040000)+, Molokai (20050000)+, Oahu (20060000)+, Kauai (20070000)+, Niihau (20080000)+
+ Natural heritage record(s) exist for this watershed
* Extirpated/possibly extirpated
Ecology & Life History
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Basic Description: A slender, long-legged shorebird with a long slender bill.
General Description: A tall slender wader with a long straight slender bill, black (male) or brownish (female) upperparts, white underparts, very long red or pink legs and feet, and a white spot above the eye; immatures have buffy edges on the dark feathers of the upperparts.
Diagnostic Characteristics: Differs from other species of stilts in having the top of the head and back of the neck solid black, sharply contrasting with the white underparts and continuous between the neck and the back; black-winged stilt has a white area of variable extent separating the black or gray of the head from the black of the back; pied stilt has an entirely white crown (Pratt et al. 1987). Differs from continental races of H. MEXICANUS in having the black extending lower on the forehead as well as around to the sides of the neck, and by having a longer bill, tarsus, and tail; gray tail feathers tend to be tipped with black (Berger 1981).
Reproduction Comments: Nesting season is March-August; clutch size is 4; incubation lasts 24 days; young stray from nest within 24 hours of hatching, remain with parents for several months (Matthews and Moseley 1990). Nests in loosely defined colonies.
Ecology Comments: Social; usually in loose groups. Moves freely between ponds and islands (Scott and Kepler 1985). Populations fluctuate with climatic variations, increasing with an increase in wetlands (Engilis and Pratt 1993).
Non-Migrant: Y
Locally Migrant: Y
Long Distance Migrant: N
Mobility and Migration Comments: Apparently many migrate between Kauai and ephemeral wetland breeding areas on Niihau; general pattern may be of arrival on Niihau after winter rains, departure for Kauai in late summer (unless wetland remain wet) (Telfer, in Engilis and Pratt 1993).
Estuarine Habitat(s): Herbaceous wetland, Tidal flat/shore
Lacustrine Habitat(s): Shallow water
Palustrine Habitat(s): HERBACEOUS WETLAND, Riparian
Habitat Comments: Frequents mudlfats along or near natural or human-made ponds and wetlands, often near coastal areas. Loafing areas generally are mudflats, mats of pickleweed, or open pasture where visibility is good and predators are few (Matthews and Moseley 1990). Nests in scrape on ground, preferentially on small sparsely vegetated islets in shallow ponds; also uses dry barren areas near shallow water; on Kauai, has successfully used man-made floating nest structures (Matthews and Moseley 1990).
Adult Food Habits: Invertivore
Immature Food Habits: Invertivore
Food Comments: Eats various aquatic organisms--worms, small crabs, insects, small fishes (Matthews and Moseley 1990). Feeds in freshwater or tidal wetlands. Often nesting and feeding areas are widely separated.
Adult Phenology: Diurnal
Immature Phenology: Diurnal
Economic Attributes Not yet assessed
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Management Summary
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Management Requirements: Exotic predators should be excluded from occupied sites and from potential habitat.
Biological Research Needs: Further investigation into optimal and suboptimal habitat needed, along with more studies on the effects of introduced predators and water pollution.
Population/Occurrence Delineation Not yet assessed
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Population/Occurrence Viability
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U.S. Invasive Species Impact Rank (I-Rank) Not yet assessed
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Authors/Contributors
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NatureServe Conservation Status Factors Edition Date: 14Feb2011
NatureServe Conservation Status Factors Author: Eilerts, R., G. Hammerson, and L. Kashinsky
Element Ecology & Life History Edition Date: 24Mar1993
Element Ecology & Life History Author(s): HAMMERSON, G.

Zoological data developed by NatureServe and its network of natural heritage programs (see Local Programs) and other contributors and cooperators (see Sources).

References
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  • American Ornithologists' Union (AOU). 1957. The A.O.U. Check-list of North American Birds, 5th ed. Port City Press, Inc., Baltimore, MD. 691 pp.

  • American Ornithologists' Union (AOU). 1983. Check-list of North American Birds, 6th edition. Allen Press, Inc., Lawrence, Kansas. 877 pp.

  • Berger, A. J. 1981. Hawaiian Birdlife. Second Edition. University Press of Hawaii, Honolulu, Hawaii. xv + 260 pp.

  • Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1992. Birds in Jeopardy: the Imperiled and Extinct Birds of the United States and Canada, Including Hawaii and Puerto Rico. Stanford University Press, Stanford, California. 259 pp.

  • Engilis, A., Jr., and T. K. Pratt. 1993. Status and population trends of Hawaii's native waterbirds, 1977-1987. Wilson Bull. 105:142-158.

  • King, W. B., compiler. 1979. Endangered birds of the world. The International Council for Bird Preservation. Smithsonian Institution Press, Washington, D.C. [Reprinted in handbook form in 1981.]

  • Matthews, J.R. and C.J. Moseley (eds.). 1990. The Official World Wildlife Fund Guide to Endangered Species of North America. Volume 1. Plants, Mammals. xxiii + pp 1-560 + 33 pp. appendix + 6 pp. glossary + 16 pp. index. Volume 2. Birds, Reptiles, Amphibians, Fishes, Mussels, Crustaceans, Snails, Insects, and Arachnids. xiii + pp. 561-1180. Beacham Publications, Inc., Washington, D.C.

  • Morrison, R. I. G., R. E. Gill, Jr., B. A. Harrington, S. Skagen, G. W. Page, C. L. Gratto-Trevor, and S. M. Haig. 2001. Estimates of shorebird populations in North America. Occasional Paper Number 104, Canadian Wildlife Service, Environment Canada, Ottawa, ON. 64 pages.

  • National Geographic Society (NGS). 1983. Field guide to the birds of North America. National Geographic Society, Washington, DC.

  • Pratt, H. D., P. L. Bruner, and D. G. Berrett. 1987. A Field Guide to the Birds of Hawaii and the Tropical Pacific. Princeton University Press, Princeton, New Jersey. 409 pp. + 45 plates.

  • Scott, J. M., C. B. Kepler, C. van Riper, and S. I. Fefer. 1988. Conservation of Hawaii's vanishing avifauna. BioScience 38:238-253. Scott, J. M., et al. 1988. Conservation of Hawaii's vanishing avifauna. BioScience 38:238-253.

  • Scott, J. M., and C. B. Kepler. 1985. Distribution and abundance of Hawaiian native birds: a status report. Pages 43-70 in Temple, S. A. (editor). Bird Conservation 2. University of Wisconsin Press, Madison, Wisconsin. 181 pp.

  • U.S. Fish and Wildlife Service (USFWS). 1985. Hawaiian Waterbirds Recovery Plan [complete and revised, includes tables]. Portland, Oregon.

  • U.S. Fish and Wildlife Service (USFWS). 1990. Endangered and threatened species recovery program: report to Congress. 406 pp.

  • Walker, R. et al. 1986. Endangered Species Information System (ESIS) - Species Record for Himantopus mexicanus knudseni (Hawaiian Stilt). Also, Range Distribution Maps for Stilt, Coot, Gallinule and Nene.

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Citation for Bird Range Maps of North America:
Ridgely, R.S., T.F. Allnutt, T. Brooks, D.K. McNicol, D.W. Mehlman, B.E. Young, and J.R. Zook. 2003. Digital Distribution Maps of the Birds of the Western Hemisphere, version 1.0. NatureServe, Arlington, Virginia, USA.

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"Data provided by NatureServe in collaboration with Bruce Patterson, Wes Sechrest, Marcelo Tognelli, Gerardo Ceballos, The Nature Conservancy-Migratory Bird Program, Conservation International-CABS, World Wildlife Fund-US, and Environment Canada-WILDSPACE."

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