(DRAFT) - Taxonomy
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
TAXONOMY
NAME - STILT, HAWAIIAN
OTHER COMMON NAMES - STILT, HAWAIIAN;STILT, HAWAII; STILT and BLACK-NECKED;LONG-SHANKS;KUKULUAEO; KUKULUAE'O; AEO;AE'O
ELEMENT CODE -
CATEGORY - Birds
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - AVES,
ORDER AND SUBORDER - CHARADRIIFORMES,
FAMILY AND SUBFAMILY - RECURVIROSTRIDAE,
GENUS AND SUBGENUS - HIMANTOPUS,
SPECIES AND SSP - HIMANTOPUS, KNUDSENI
SCIENTIFIC NAME - HIMANTOPUS HIMANTOPUS KNUDSENI
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Hawaiian Stilt
Himantopus himantopus knudseni (Stejneger, 1887)
KINGDOM: Animal GROUP: Bird
PHYLUM: Chordata CLASS: Aves
ORDER: Charadriiformes FAMILY: Recurvirostridae
The Hawaiian stilt is a large waterbird, 16 inches long and about
12 inches high. The sexes are similar; black above and white below,
with a white forehead. The black on the head extends low on the
forehead and around the side of the neck to a greater degree than the
continental black-necked stilt. Adults have a red eye-color, a
straight black bill, long legs ranging from light to dark pink, and
sometimes a narrow dark terminal tail band. Adult males have glossy
black backs, while females are dull brown in color. Sub-adults have
browner back feathers, grey to greyish-pink legs, dull brown bills, a
brown eye iris, the tail is tipped with grey, and the white neck
plumage extends dorsally under the eye. Downy young are variegated
brown, buff or grey, black, and lighter below with a white egg
"tooth." Eggs are an olive-brown or buff color and variegated with
dark brown or black speckling or blotching over the entire surface
averaging 1.9 by 1.36 inches (01,02,03,04,05,06). Refer to (13) for
Taxonomy - 1 (DRAFT) - Taxonomy
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
further details.
The Hawaiian subspecies is larger in all respects than its
mainland counterpart. Average male measurements are:
weight-199 g;
bill-74.1 mm;
wing-238.6 mm;
tail-76.3 mm; and
tarsometatarsus-123.9 mm.
Average females measurements are:
weight-206.2 g;
bill-74.2 mm;
wing-231.6 mm;
tail-76.0 mm; and
tarsometatarsus-116.9 mm (01).
The Hawaiian stilt was first reported in 1873 by Pelzein who
named it Himantopus nigricollis. Judge Dole designated the same bird
H. candidus in 1879. Dr. O. Finsch reported this classification in
Ibis (1880) and considered it identical to Himantopus mexicanus.
Stejneger described the type specimen in 1887 from the island of
Kaua'i and named it H. knudseni after V. Knudsen who collected it for
comparison with the North American species (01,07). In the 1940's it
was described as H. himantopus knudseni by one author (08). The AOU
(1957) made the mainland form monotypic (H. mexicanus) and excluded
the Hawaiian bird all together which meant the latter was a separate
species (i.e., the taxonomic name Himantopus h. mexicanus became
H. mexicanus). The 33rd AOU supplement (1976) added a subspecific
classification H.m. mexicanus to distinguish between the Hawaiian race
(H.m. knudseni) and the South American race (H.m. melanurus) (01).
Some believe that there are two distinct species, H. mexicanus
(black-necked stilt) and H. knudseni Stejneger, 1887 (Hawaiian stilt).
H. mexicanus (including knudseni) is considered by others conspecific
with the old world H. himantopus (Linnaeus, 1758), the pied or black-
winged stilt; others maintain the two constitute a superspecies. In
fact, all members of the genus may constitute a superspecies (09).
Synonyms to the common name Hawaiian stilt include; Hawaii stilt,
black-necked stilt, long-shanks, kukuluaeo, kukuluae'o, aeo and ae'o.
The type specimen resides in the U.S. National Museum,
Washington, DC (No. 110024; Kaua'i, Hawaiian Islands; Valdemar Knudsen
collection) (07). Specimens for study can be found at the American
Museum of Natural History in Washington, DC; the B.P. Bishop Museum in
Honolulu, HI; and the British Museum of Natural History in London,
England (15). Specimens, photographs, and descriptions are on file at
the State Division of Forestry and Wildlife, Honolulu, HI (10).
Taxonomy - 2 (DRAFT) - Status
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
Federal Migratory
Commercial/consumption
Game (Consumptive Recreational)
Non-consumptive recreational
Ornamental
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Hawaiian stilt (Himantopus himantopus knudseni) has been
designated an Endangered species pursuant to the Endangered Species
Act of 1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C.
1531-1540), as amended. The subspecies has this status wherever found
including the State of Hawaii.
This subspecies is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild
animal (alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
The species is protected by the Migratory Bird Treaty Act
(16 U.S.C. 703-711 et seq.; 50 CFR 10.13). The species Himantopus
mexicanus (black-necked stilt) is protected by the Migratory Bird
Treaty Act. According to the 1983 AOU checklist the Hawaiian stilt
is a subspecies of H. mexicanus. The Migratory Bird Treaty Act
therefore intends to include this subspecies for protection.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
DOD -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control. Also responsible for
management/recovery on Department of Defense lands.
Status - 1 (DRAFT) - Status
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Hawai'i
DESIGNATED STATUS: Endangered
ADMINISTRATIVE AGENCY: Hawai'i Division of Forestry and
Wildlife, Department of Land and Natural
Resources
STATE STATUTE: Chapter 195D, Hawai'i Revised Statutes
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
The Hawaiian stilt is listed as Rare in the IUCN Red Data Book.
This species is not listed in CITES, however, this species is listed
by the Convention on Nature Protection and Wildlife Preservation in
the Western Hemisphere, 1970.
ECONOMIC STATUSES:
This is one of the many endemic birds of Hawai'i sought by bird
watchers. Early Hawaiians may have taken the stilt for food or its
feathers. The species was at one time hunted for sport.
70/08/25:35 FR 13519/13520 - Proposed listing as Endangered
70/10/13:35 FR 16047/16048 - Final rule; listing as Endangered
79/05/21:44 FR 29565/29577 - Five year review
85/04/05:50 FR 13707/13722 - Revised list of Migratory Birds
85/07/22:50 FR 29901/29909 - Five year review
Status - 2 HABITAT ASSOCIATIONS
HABITAT - AQUATIC
TERRESTRIAL
INLAND AQUATIC
COASTAL
LAND USE -
Residential
Transportation, communications, and Util
Mixed Urban or Built-up Land
Cropland and Pasture
Streams and Canals
Lakes
Reservoirs
Bays and Estuaries
Nonforested Wetland
Sandy Areas other than Beaches
Bare Exposed Rock
Transitional Areas
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
1EM
Lacustrine, littoral UB
Lacustrine, littoral FL4
Lacustrine, littoral FL3
Lacustrine, littoral FL2
Lacustrine, littoral FL1
Lacustrine, limnetic UB
Palustrine UB
Palustrine FL4
Palustrine FL3
Palustrine FL2
0FL
Palustrine EM1
Estuarine, intertidal FL4
Estuarine, intertidal FL3
Estuarine, intertidal FL2
Estuarine, intertidal FL1
Estuarine, intertidal BB2
Marine, intertidal FL3
Marine, intertidal FL2
Marine, intertidal FL1
Marine, intertidal UB
Marine, subtidal UB
COMMENTS ON HABITAT ASSOCIATIONS -
The Hawaiian stilt is associated with fresh, saline, and brackish
shallow water environments, primarily in coastal or lowland areas
(below 150 meters or 500 feet in elevation) on all major Hawaiian
Islands. They are distributed primarily in coastal strips on
each island where they are extant, but on Maui they may extend their
range up into agricultural lands that are sprinkled with reservoirs.
On Kaua'i stilts are found in foothill impoundments and wetlands. The
species occurs in a multitude of political subdivisions including
military bases, Federal and State refuges and sanctuaries; County
reservoirs, parks, and sewage treatment plants; State airport lands
Habitat Associations - 1 and private agricultural areas (02,05,06). Three habitats can be
differentiated: nesting, feeding, and loafing.
Nesting habitats usually include islets scattered in bodies of
shallow water, clumps of vegetation in flooded areas, barren soil
(preferred substrate) protruding from shallow water, floating patches
of vegetation, or limestone rock areas in: 1) Irrigation reservoirs;
2) settling basins; 3) natural or man-made ponds; 4) marshes; 5) taro
patches; 6) silted fishponds; and 7) salt evaporation pans.
Feeding areas in fresh water environments include irrigation
reservoirs, drainage ditches, sugar-cane settling basins, ponds, taro
patches, sewage oxidation ponds, ephemeral depressions, flooded
pastures, and natural marshes. Brackish feeding habitats include
inshore reefs and mudflats, silted beach areas, and breached coastal
fishponds.
Loafing habitats in all three water regimes are open spaces in
mudflats, prostrate vegetative mats, pasture lands, and large islands
in offshore marine mudflats and fresh or brackish ponds (01,02,03,10,
14). On the island of Kaua'i, taro fields at the Hanalei NWR and
environs, wet pastures and settling basins at Kekaha, Koloa, and
Lihu'e are favored over man-made reservoirs. On Ni'ihau, large
natural ponds and artificial lakes harbor the majority of stilts. The
species is the most broadly distributed among diverse habitats on the
island of O'ahu. Although they use scattered habitats on Moloka'i,
they are most abundant around Kaunakakai and at the Kakahaia NWR. The
species is not found on Lana'i which lacks suitable wetlands. On
Maui, stilts are most abundant in the large ponds at Kanaha and
Kealia. They are confined to the western coastal brackish ponds
('Aimakapa and 'Opae'ula) on the island of Hawai'i (10,15).
Specific vegetative associations have not been fully described,
but stilts are associated with a variety of terrestrial plants (i.e.,
Cynodon dactylon and Desmanthus virgatus); wetland plants (i.e., Batis
maritima, Brachiaria mutica, Scirpus validus, Cyperus alternifolius,
Ludwigia octivalris, and Eleocharis sp.); and aquatic species (i.e.,
Ruppia maritima) (16). Stilts have been noted seeking the lee side of
soil or rock outcrops or brush vegetation during high winds or storms
(01,10,20).
Environmental descriptions for the Hawaiian stilt are scarce.
In a limited study of brackish environments on Kaua'i, aquatic
material included mud-clay, fine silt, detritus/ooze on coral
substrate, coral sand and limestone, Malama/Hanalei/Puhi stony silty
clay loam, Lawai/Kalapa silty clay, Kalihi clay and mud-riprap lava
rock. Annual water fluctuations varied from .06 to 3.6 meters.
Alkalinity varied from 30 to 250 ppm and the pH from 5.8 to 8.1.
Dissolved oxygen ranged from 1.64 to 7.60 ppm (16). Mean salinities
in one brief study at the Nu'upia Ponds on O'ahu varied from 35 to 64
ppt (17). In yet another brief study, salinity ranged from 4 to 68
ppm (01). On Ni'ihau, the known distribution includes all wetlands,
lakes, ditches, ponds, and reservoirs on the northwest coast and
south-central plain of the island. As the island is very dry
(aird with riparian areas) for most of the year, use by stilts is
greater in the winter when rains fill the intermittent lakes. Other
environmental parameters have not been described for this species.
Stilts may also be found within or adjacent to military bases, State
airports, and industrial areas where suitable habitat exists (see the
field N-OCCURRENCE for specifics). The stilts also occur along
coastal highways and powerlines along these highways have accounted
for some deaths due to collision.
Habitat Associations - 2 (DRAFT) - Food Habits
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
CARNIVORE
LIFESTAGE FOOD FOOD PART
General Arthropods
General Crustaceans
General Molluscs
General Worms
General Fish
Food Habits - 1 (DRAFT) - Environment Associations
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G Coastal Wetlands: Mangrove swamps
G Coastal Features: Vegetated offshore islands
G Terrestrial Features: Depressions
G Terrestrial Features: Rock outcrops
G Human Association: Farm ponds
G
Environment Associations - 1 (DRAFT) - Life History
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
Studies of gut samples in the Hawaiian stilt are lacking, but the
stilt is known to take polychaete worms, crabs, aquatic insects and
various fishes (i.e., mullet, tilapia, and mosquito fish). The
Hawaiian stilt is probably opportunistic, consuming a wide variety of
other aquatic organismis. Data on the North American race confirms
feeding on several types of insects (Heteroptera, Coleoptera, Diptera,
Trichoptera, and Odonata) as well as molluscs, fish and some
vegetable matter (03).
An Hawaiian stilt found at Mana Base Pond (evidently shot) was
examined. Its gizzard contents included fish bones and scales,
(primarily Gambusia sp.) one leg part of an unidentified Coleoptera,
and considerable grit (18).
The Hawaiian stilt probably feed on small fish, invertebrates,
crustaceans, worms, and insects in marine, brackish and fresh water
environments; including pond edges, mudflats, sugarcane trash piles,
and settling basins (02).
Seasonal variations in food consumption, variations in food items
by age, or food essentiality are unknown. In the few studies done,
fish predominate in the diet (80 percent) (16).
HOME RANGE/TERRITORY:
No specific studies on territoriality or breadth of range during
breeding or non-breeding periods have been conducted for this species.
However, stilts are considered semi-colonial nesting species and
overlapping nesting territories are mutually defended by mated pairs.
A nesting territory in one instance was 10 to 20 meters in radius and
was actively defended against all non-conspecific intruders.
Distraction behavior, including wing-flagging, alarm calling, and
"dive bombing," have been described (01).
When the young mature, families and flocks concentrate in feeding
areas. Breeding and feeding areas may be diverse and at great
distances form each other. Censuses during the non-breeding season
reveal a much different distribution of stilts, usually over a wider
geographical area (02,04,15,19). Little else is known concerning the
Hawaiian stilt and territoriality.
PERIODICITY:
There have been no studies of periodicity for the Hawaiian stilt.
They are essentially diurnal and, based on a few daily censuses, are
more active in the early morning and later afternoon (10). Flight at
night has been recorded on a few occasions (01,10,20). Bird banders
in California net stilts "regularly" at night in good habitat,
whether the stilts feed at night has not been proven. Two distinct
seasonal patterns of distribution (i.e., breeding season and non-
breeding season) have been described (02,04,10). On one study of a
feeding habitat at Ke'ehi Lagoon on O'ahu, stilts virtually deserted
the site during February through May presumably for breeding grounds
(20). The Kaua'i-Ni'ihau population has a pattern of using the island
of Ni'ihau during the breeding season when there is sufficient water
and the island of Kaua'i during the non-breeding season and during
Life History - 1 (DRAFT) - Life History
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
exceptionally dry years.
MIGRATION PATTERNS:
This species is non-migratory but is quite mobile during the non-
breeding season. Inter-island movements have been documented by
virtue of limited banding, recovery studies and sight records. "Total
island counts" remain relatively constant while distribution varies
greatly with season, weather patterns, etc. Movement between Kaua'i
and O'ahu, Maui and O'ahu, and Moloka'i and O'ahu has been verified by
sightings of banded individuals. The Kaua'i-Ni'ihau movement is
assumed as a result of census records which are weighted to Ni'ihau
during periods of good rainfall and to Kaua'i during dry periods (02,
03,04,08,15).
COVER/SHELTER REQUIREMENTS:
With the exception of nesting/brooding site parameters,
comprehensive studies of cover/shelter requirements have not been
conducted. By virtue of their preference for open, low vegetation and
barren areas, cover does not appear to be a major necessity for the
Hawaiian stilt. Stilts have been noted seeking the lee side of soil
or rock outcrops or brush vegetation during high winds or storms (01,
10,20).
REPRODUCTIVE SITE REQUIREMENTS:
Pre-nuptial displays have been noted on land, in the water, and
in the air in wetland environments. Hawaiian stilts nest in fresh or
brackish ponds, mudflats, taro patches, and marshes (01,03). In one
study, 80 percent of the nests were located on islands ranging from 20
cm to 20 m in size (01). The stilts readily use artificial structures
such as tire mounds and floating devices (16,21). Bare ground is the
preferred substrate (64 to 89 percent), but nests have been found on
live vegetation, dead vegetation, and floating mats of vegetation and
limestone mounds (01,02,03,16,22). The nest itself is a scrape of
bare soil or sand lined or surrounded by small pebbles, sticks,
shells, pieces of soft vegetation, dirt clods, bird droppings, or
foreign matter (debris from man) (01,16,22). Pickleweed (Batis
maritima) is the predominant plant associated with stilt nests
(01,03). Cover recorded at nest sites included large sticks, rocks,
clumps of small annual plants, and boards. Sources of shade are
sometimes found within a few feet of the nests (01,22). In one study
the mean distance of the nests from water was 144 cm and the mean
height of the nest above the water surface was 20 cm. The mean height
of the nest structures was 1.2 cm, the mean outer diameter of the nest
was 19 cm, and the mean depth of the nest cup was 3 cm (01). During
extended periods of high winds, nests are placed in lee situations.
Nursery areas are usually shallow areas on edges of habitats where
young can find food. Hawaiian stilt nests are usually 75 to 100 feet
(25 to 33 meters) apart and false nests built close to actual nests
have been documented.
REPRODUCTIVE CHARACTERISTICS:
The Hawaiian stilt is monogamous, but little else is known about
the minimum/maximum breeding age and mating relationships. There is
Life History - 2 (DRAFT) - Life History
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
one reproductive period beginning as early as February and extending
as late as August, with a peak in May and June. Pairing occurs in the
winter and early spring (01,02,03,13). The female usually initiates
mating by extending the neck, bobbing the head, shaking the bill, and
then remaining still with her neck extended. The male's behavior
begins with preening followed by bill shaking, body bobbing, and more
preening of his breast and back. At mating (usually in water), the
male approaches the female from behind (either side) and mounts her
back, folding his legs and extending his neck alongside the female's
out-streched neck. Post-coital behavior consists of the male
extending one wing over the back of the female and the pair crossing
bills (01). The incubation period is usually 24 days (range: 23 to 26
days). Adults share in the incubation. In one study, the average
clutch size was 3.6 eggs (range: 2 to 7 eggs); the mean hatching rate
was 2.1 per nest; the fledging success was 23 percent; and the mean
brood size was 1.5 per pair (01).
PARENTAL CARE:
Both parents share in the care of the young, including brooding,
protection from predators, and defending feeding sites. Adults do not
feed the young after hatching. Young are precocial and can walk and
swim soon after hatching. Within 24 to 36 hours after the first egg
hatches and a few hours after the last egg is hatched, the parents
lead the young away from the nest site. Young are capable of limited
flight after 24 to 31 days (02,03). The family group is retained
long after hatching as pairs with fully feathered young have been
noted during the fall and winter months (01). Little else has been
recorded regarding parental care.
POPULATION BIOLOGY:
Although annual censuses of Hawaiian stilts have been conducted
since 1956, no systematic studies of population biology have been
made. In one analysis of the results of these surveys, it was found
that pre-breeding populations averaged 900 and post-breeding
populations averaged 1,100 individuals, statewide. The average annual
production was about 200 young, and the population turned over every
five years, indicating stability on the long term (15). During the
period 1981 to 1984, sex ratios of adult stilts were approximately
1:1, slightly favoring males. Sampling of age ratios during the
spring recruitment surveys for the period resulted in a ratio of 70
percent adults to 30 percent young (23,24,25). However, in a limited
study on O'ahu, the overall reproductive success was only 13 percent
of the eggs laid. Longevity has not been studied. Current limiting
factors include predation (by far the greatest direct impact), habitat
conversion, human disturbance, disease, flooding of nest sites, and
excessive vegetation growth in breeding habitats. The present
management goal is to achieve a stable population level of 2,000 birds
on existing habitats through management and protection (01,02,03).
SPECIES INTERRELATIONSHIPS:
Hawaiian stilts have no direct causal relationship with any one
species, but known predators on the eggs and young include the
domestic dog (Canis familiaris), mongoose (Herpestes auropuntatus),
Life History - 3 (DRAFT) - Life History
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
feral cats (Felis catus), the black-crowned night heron (Nycticorax
nycticorax hoactli), and the ruddy turnstone (Arenaria interpres).
Possible predators include rats (Rattus spp.), owls (Tyto alba, Asio
flammeus sandwichensis), the common mynah (Acridotheres tristis), and
the cattle egret (Bulbulcus ibis) (01,02,03).
OTHER LIFE HISTORY DESCRIPTORS:
No aditional information is available at this time.
Life History - 4 (DRAFT) - Management Practices
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Prescribed/controlled burning of habitat
Beneficial Restricting/regulating human disturbance of populations
Beneficial Developing/maintaining stream structures
Beneficial Maintaining/Controlling Water Flow
Beneficial
Beneficial Developing/maintaining/protecting wetlands
Beneficial Maintaining undisturbed/undeveloped areas
Beneficial Restricting/regulating human use of habitats
Beneficial Land Acquisition
Beneficial Water Right Acquisition
Beneficial Controlling pollution [thermal, chemical, physical]
Beneficial Creating Artificial Habitat/Nesting Structure
Beneficial Reforestation
Beneficial Maintaining Early Stages of Succession
Beneficial Controlling/Removing Nonnative Vegetation
Beneficial Controlling/Removing Native Vegetation
Beneficial Stocking captive-reared wild-strain animals
Beneficial Transplanting wild animals
Beneficial Disease Control Measures
Beneficial Rehabilitating Individuals
Beneficial Controlling/Removing Native Vertebrates
Beneficial Controlling/Removing Exotic Vertebrates
Beneficial Controlling/Removing Feral Animals
Adverse Subsistence Hunting/Fishing/Trapping
Existing Subsistence Hunting/Fishing/Trapping
Adverse Poaching
Existing Poaching
Adverse Sport Hunting/Fishing
Existing Sport Hunting/Fishing
Adverse Boating
Existing Boating
Adverse Disease
Existing Disease
Adverse Parasites
Existing Parasites
Adverse Predation
Existing Predation
Adverse Rural Residential/Industrial Areas
Existing Rural Residential/Industrial Areas
Adverse Recreational development
Existing Recreational development
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Transmission Lines/Towers
Existing Transmission Lines/Towers
Adverse Siltation
Existing Siltation
Adverse Draining wetlands, marshes, ponds, lakes
Existing Draining wetlands, marshes, ponds, lakes
Management Practices - 1 (DRAFT) - Management Practices
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
RESULT MANAGEMENT PRACTICE
Adverse Water Level Stabilization
Existing Water Level Stabilization
Adverse Water Level Fluctuation
Existing Water Level Fluctuation
Adverse Flooding
Existing Flooding
Adverse Irrigating
Existing Irrigating
Adverse Reservoirs
Existing Reservoirs
Adverse Dredging
Existing Dredging
Adverse Shoreline modification/development
Existing Shoreline modification/development
Adverse Applying fertilizers
Existing Applying fertilizers
Adverse Applying herbicides
Existing Applying herbicides
Adverse Applying pesticides
Existing Applying pesticides
Adverse Environmental Contamination/Pollution
Existing Environmental Contamination/Pollution
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse
Existing
Adverse Vegetation Composition Changes
Existing Vegetation Composition Changes
COMMENTS ON MANAGEMENT PRACTICES -
The impact of the early Hawaiian's on the ae'o is not documented,
but it is possible the stilts were collected for food or feathers.
With the advent of modern man, hunting seasons were held annually
until 1914 when the season was closed (03,05,11) and by 1939 hunting
of this species was prohibited (02). Habitat loss was, and is by far
the primary factor in the decline of the species. Taro fields
(aquaculture) cultivated by Hawaiians provided alternative habitat,
but by 1960 the acreage declined drastically. Rice culture began in
1860 but was abandoned in 1963 eliminating this man-made habitat. The
alteration or elimination of natural habitats, including marshes,
mudflats, estuaries, bays and shorelines, accelerated with the
progressive development of hotels, subdivisions, golf courses,
shopping centers, sanitary land fills, dumps, military bases,
airports, highways and industrial areas threaten this species even
where some populations are presently known to occur. Changing or
expanding agricultural practices either subplanted key wetlands or
altered them by contributing silt, trash, fertilizers, pesticides or
biocides which affected water quality or food organism viability.
Channelization and water diversions have adversely affected ideal
water levels for nesting and protection from predators. Deposition of
Management Practices - 2 (DRAFT) - Management Practices
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
sewage in wetlands has caused excessive plant growth along with
fertilizers that have altered the habitat toward being more unsuitable
to the stilt. Exotic plant (grasses, floating vegetation, etc.)
encroachment in these environments has eliminated shallow open water
and mudflats favored by the stilt (01,02,03,10,11). Habitat loss has
been most pronounced on the island of O'ahu where 80 percent of the
human population of Hawai'i resides on only 15 percent of the total
land area (12). The same could be said for the urban and rural resort
foci on the other islands (Kahului, Maui; Hilo, Hawai'i; Po'ipu,
Kaua'i; and Kaunakakai, Moloka'i). Predation also is severe around
developed areas occupied by dogs, cats, rats, and mongooses. These
impacts have been somewhat ameliorated by stilt habitats created by
man such as ponds, sugar-cane settling basins, and reservoirs.
Although some illegal hunting and human disturbance contributes
to stilt mortality, predation is paramount. Black-crowned night
herons and possibly owls also prey on the ground-nesting Hawaiian
stilt. The contribution of diseases and parasites in reducing stilt
populations has not been studied but may be a factor. Occasionally
mortality occurs as a result of collision with power lines which
are common along some of the coastal highways in areas of known stilt
occurrence (01,02,03,08,10,11). All of the factors which caused the
decline of the stilt in Hawai'i, except legal hunting, are still
operative. However, modern environmental and wildlife protection laws
and the acquisition of key habitats for perpetual sanctuaries has
decelerated past downward population trends for this species (01,02,
03,10,13).
Future threats to the species will continue to include habitat
loss and alteration, contamination of habitats, and predation despite
governmental controls and actions. Disease, parasitism, and pollution
may become factors that push this species into extinction because of
expanding urbanization and the proliferation of new disease vectors.
Without new habitat acquisition, intensified predator control,
prevention of pollution, and quick responses to outbreaks of disease
or poisoning, stilt populations may decline. Monitoring populations
and ecological studies on habitats will be necessary to refine
management to counter future threats to the species (02,03,10,13,14).
APPROVED PLAN:
U.S. Fish and Wildlife Service. 1985. Recovery Plan for the Hawaiian
Waterbirds. U.S. Fish and Wildlife Service, Portland, OR. 99 pp.
The Hawaiian stilt has declined mainly due to the loss or
degradation of habitat and to nest predation by introduced mammals.
The revised Hawaiian Waterbirds Recovery Plan states as its prime
objective to maintain a minimum population of 2000 stilts with a
stable distribution of habitats as outlined in the original 1978
Recovery Plan. Progressive down-listing and delisting can be made
once specified areas of habitat are secured and the population rises
to 2000 or more birds for six consecutive years.
Recommended recovery actions include:
1) Securing specified habitats on five islands.
Management Practices - 3 (DRAFT) - Management Practices
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
2) Development of cooperative agreements among the State and Federal
governments and private landowners to protect habitats from
adverse development and to provide for management of wetland
habitat on private lands and on government lands not held by
wildlife agencies. Obtaining water rights may be necessary on
some lands.
3) Use regulatory authority and provide technical assistance to
landowners and agencies to protect and enhance wetlands
(especially for development actions).
4) Use existing regulatory authorities to uphold land use
regulations. Additional regulations would be helpful.
5) Identify additional habitat.
6) Manage wetlands to maximize productivity by controlling water
levels and salinity, managing for desireable plants and
controlling or removing undesireable vegetation (often exotics),
limiting human access (especially to sensitive habitats),
managing for habitat diversity (predator free inlets, shallow and
deep water, dense emergent vegetation, etc.), controlling
predators (introduced mammals, feral cats and dogs, and native
herons and egrets), providing preventative disease control
measures, minimizing contamination of habitats by toxic
substances, and rehabilitating and releasing injured or displaced
individuals.
7) Identify sites for restoration or creation of waterbird habitats.
8) Conduct management related research.
9) Continue population monitoring and develop a more efficient means
of censusing.
10) Generate public awareness and support for waterbird recovery
programs through education and the dissemination of information.
11) Investigate the need for propagation and reintroduction of
captive birds or translocation of wild adults.
Recovery actions accomplished and in progress are almost too
numerous to list. Foremost are the creation of (1) State sanctuaries
at Kanaha and Kealia Ponds and at Paiko Lagoon and (2) National
Wildlife Refuges, including Hanalei, Huleia, Kakahaia, Pearl Harbor,
and James Campbell NWRs. The USFWS is negotiating the acquisition of
Kealia Pond. The stilts may eventually spread on its own to other
habitats not currently occupied, or could be introduced. Management
of these refuges is controversial, particularly concerning how water
levels and salinity should be regulated to maximize productivity of
endemic waterbirds. A research project funded by the USFWS and
conducted by the University of Missouri is currently investigating
problems of habitat imporvement and predator control for Hawaiian
waterbirds. Another USFWS research project is the study of the
biology and control of the small Indian mongoose. Several of the NWRs
have been fenced and are subject to predator control. Development
projects reviewed by the Environmental Services Office of the USFWS
have often been required to take into account the protection or
improvement of waterbird habitat which has led to the creation of new
habitat, such as Ho'omaluhia Park and Punaho'olapa wetlands.
Management Practices - 4 (DRAFT) - References
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Coleman, R.A. 1981. The reproductive biology of the Hawaiian
subspecies of the black-necked stilt, Himantopus mexicanus
knudseni. Thesis, Penn. State Univ., University Park, PA. 106 pp.
02 U.S. Fish and Wildlife Service. 1985. Recovery Plan for the
Hawaiian Waterbirds. U.S. Fish and Wildlife Service, Portland, OR.
99 pp.
03 Shallenberger, R.J. 1977. An ornithological survey of Hawaiian
wetlands: Vol. 1. U.S. Army Engineer Dist. (Ahuimanu Productions),
Honolulu, HI.
04 Hawaii Division of Forestry and Wildlife. 1982. Surveys and
inventories of waterbirds and their habitats in the state of
Hawaii. Job Progress Rept. W-18-R-6, Job R-III-A, February 1, 1981
to January 31, 1982. 32 pp.
05 Bryan, W.A. 1901. A key to the birds of the Hawaiian group.
Bishop Museum Press, Honolulu, HI. 67 pp.
06 Wilson, S.B. and A.H. Evans. 1893. Aves hawaiiensis: Birds of
the Sandwich Islands. Arno Press, NY, NY.
07 Stejneger, L. 1887. Birds of Kauai collected by Knudsen. Proc.
U.S. Nat. Mus., Washington, DC. Pp. 81-82.
08 Munro, G.C. 1944. Birds of Hawaii. Tongg Publ. Co., Honolulu.
09 American Ornithologists Union. 1983. Checklist of North American
birds, 6th edition. American Ornithologists Union, Lawrence,
Kansas. 877 pp.
10 Walker, R.L. 1985. Personal knowledge. 46-305 Hoauna Street,
Kaneohe, HI, 96744.
11 Schwartz, C.W., and E.R. Schwartz. 1949. A reconnaissance of the
game birds in Hawaii. Hawaii Board of Commissioners of Agriculture
and Forestry, Honolulu, HI.
12 Anon. 1985. The State of Hawaii data book. State Dept. of Plan.
and Economic Develop, Honolulu, HI. 762 pp.
13 Berger, A.J. 1972. Hawaiian birdlife. The University Press of
Hawaii, Honolulu, HI.
14 U.S. Fish and Wildlife Service. 1970. Hawaii Endangered
waterbirds. USDI/FWS, Portland, OR. 32 pp.
15 Banko, W.E. 1985. History of endemic Hawaiian birds. Part 1.
Population histories-species accounts: freshwater birds. CPSU/UH
Avian History Report 10 (Aeo: 1-234p). Located at: University of
Hawaii at Manoa, Dept. of Botany (Smith, C.W., Unit Director),
Honolulu, HI.
16 Telfer, T.C. 1976. Description of waterbird habitats as releated
to food availability and feeding behavior of Endangered waterbird
species on the islands of Kauai and Oahu. Job progress report;
W-18-R-1, Job R-III-D, July 1, 1975 to June 30, 1976. Hawaii Div.
of For. and Wildl., Honolulu, HI. 18 pp.
17 Hawaii Division of Forestry and Wildlife. 1978. Description of
waterbird habitats as releated to food availability and feeding
behavior of Endangered waterbird species on the islands of Kauai
and Oahu. Job progress report; W-18-R-3, Job R-III-D, July 1, 1977
to June 30, 1978. Hawaii Div. of For. and Wildl., Honolulu, HI.
References - 1 (DRAFT) - References
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
33 pp.
18 Hawaii Division of Forestry and Wildlife. 1980. Description of
waterbird habitats as releated to food availability and feeding
behavior of Endangered waterbird species on the islands of Kauai
and Oahu. Job progress report; W-18-R-4, Job R-III-D, September 1,
1978 to August 31, 1979. Hawaii Div. of For. and Wildl., Honolulu,
HI. 22 pp.
19 Hawaii Division of Forestry and Wildlife. 1980. Surveys and
inventories of waterbirds and their habitats in the state of
Hawaii. Job Progress Rept. W-18-R-4, Job R-III-A, July 1, 1978
to January 31, 1980. 56 pp.
20 Walker, R.L. 1978. Final report: Keehi Lagoon and mitigation
areas bird survey. The R.M. Parsons Co., Honolulu, HI. 14 pp.
21 Hawaii Division of Forestry and Wildlife. 1982. Evaluation of
Endangered waterbird habitat improvements. Job Progress Rept.
W-18-R-6, Job R-III-A, October 1980 to September 1981. Hawaii Div.
of For. and Wildl., Honolulu, HI. 28 pp.
22 Hawaii Division of Forestry and Wildlife. 1981. Limited study of
nesting by stilt on the islands of Maui, Oahu and Kauai. Job
Progress Rept. W-18-R-5, Job R-III-C, July 1, 1979 to June 30,
1980. Hawaii Div. of For. and Wildl., Honolulu, HI. 8 pp.
23 Hawaii Division of Forestry and Wildlife. 1981. Surveys and
inventories of waterbirds and their habitats in the state of
Hawaii. Job Progress Rept. W-18-R-5, Job R-III-A, February 1, 1980
to January 31, 1981. 31 pp.
24 Hawaii Division of Forestry and Wildlife. 1983. Surveys and
inventories of waterbirds and their habitats in the state of
Hawaii. Job Progress Rept. W-18-7, Job R-III-A, February 1, 1982
to January 31, 1983. 35 pp.
25 Hawaii Division of Forestry and Wildlife. 1984. Surveys and
inventories of waterbirds and their habitats in the state of
Hawaii. Job Progress Rept. W-18-R-8, Job R-III-A, February 1, 1983
to January 31, 1984. 33 pp.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Armstrong, R.W., (ed.). 1973. Atlas of Hawaii. The University
Press of Hawaii, Honolulu.
02 Banko, W.E. 1985. History of endemic Hawaiian birds. Part 1.
Population histories-species accounts: Freshwater birds. CPSU/UH
Avian History Report 10 (Aeo: 1-234p). Located at: University of
Hawaii at Manoa, Dept. of Botany (Smith, C.W., Unit Director),
Honolulu, HI.
03 Berger, A.J. 1972. Hawaiian birdlife. The University Press of
Hawaii, Honolulu.
04 Coleman, R.A. 1981. The reproductive biology of the Hawaiian
subspecies of the black-necked stilt, Himantopus mexicanus
knudseni. Penn. State Univ, University Park, PA. 106 pp.
05 U.S. Fish and Wildlife Service. 1985. Recovery Plan for the
Hawaiian Waterbirds. U.S. Fish and Wildlife Service, Portland, OR.
99 pp.
06 Walker, R.L. 1985. Personal knowledge. 46-305 Hoauna Street,
References - 2 (DRAFT) - References
Species STILT, HAWAIIAN
Species Id ESIS101013
Date 14 MAR 96
Kaneohe, HI, 96744.
07 Munro, G.C. 1944. Birds of Hawaii. Tongg Publ. Co., Honolulu.
08 Shallenberger, R.J. 1977. An ornithological survey of Hawaiian
wetlands: Vol. 1. U.S. Army Engineer Dist. (Ahuimanu Productions),
Honolulu, HI.
09 Hawaii Division of Forestry and Wildlife. 1980. Surveys and
inventories of waterbirds and their habitats in the state of
Hawaii. Job Progress Rept. W-18-R-4, Job R-III-A, July 1, 1978 to
January 31, 1980. 56 pp.
References - 3