Kealia Pond is one of the largest natural wetlands in Hawai`i and occupies a natural basin along the south-central shoreline of Maui. Kealia Pond National Wildlife Refuge was established in 1992 to preserve and enhance wetland habitat for endangered waterbirds, primarily Hawaiian Stilts and Hawaiian Coots, and to provide dependable habitat for migratory wetland birds and wildlife-dependent opportunities for the public. The refuge consists of a large open water pond, adjacent mudflats and shoreline vegetation, and several smaller ponds that were created in the 1970s for aquaculture projects. The large central pond varies in size seasonally, from as low as 40 hectares (100 acres) when water recedes in the hot, dry summer months, to about 182 hectares (450 acres) when water level rises during winter rains from November-March. Recent reconfiguration of the aquaculture ponds through a cooperative agreement with Ducks Unlimited resulted in repair and enhancement of 25 wetland acres and development of an additional water supply that will help provide consistent waterbird habitat. Most of the refuge consists of a single unit centered on the pond, but the 24-hectare (60-acre) Ma`alaea Flats area is separated from the rest of the refuge by a busy road.

Ornithological Summary

Kealia Pond supports one of the largest concentrations of wetland birds in Hawai`i. It is an important breeding, feeding, and resting area for endangered Hawaiian Stilts and Hawaiian Coots, and the refuge was created to protect these two species in particular. During spring and summer when water levels recede, the refuge may harbor almost half the entire population of Hawaiian Stilts, with a maximum of 1079 individuals observed in July 2003. Hawaiian Coot numbers peak when water levels are higher, with a maximum of 614 birds observed in February 2001. The Hawaiian Duck or Koloa was reintroduced to Maui in the 1980s, but hybridization with feral Mallards has occurred and is a continuing problem. Most Koloa-like ducks at Kealia Pond are probably hybrids, but they can be difficult to distinguish. The endangered Hawaiian Common Moorhen is not currently found on Maui, but it once inhabited all of the main Hawaiian Islands. Recovery plans call for reintroduction of the species throughout its former range, and Kealia Pond is one of the leading sites for possible reintroduction.

Kealia Pond also supports a variety of migratory shorebirds and waterfowl from August-April. Some species occur primarily during migration, but others are present throughout the winter months. Peak numbers of migrants observed from 1995-2004 include 253 Northern Pintails, 327 Northern Shovelers, 802 Pacific Golden Plovers, 61 Wandering Tattlers, 210 Ruddy Turnstones, and 171 Sanderlings. Black-crowned Night-herons are resident in large numbers, with up to 378 present simultaneously. Although not large by continental standards, these represent some of the largest concentrations of these species in the Pacific region. Over 30 additional species of migrants use the wetland on a regular basis, and numerous vagrants have appeared over the years, making Kealia Pond one of the top sites for wetland birding in Hawai`i.

Conservation Issues

The greatest threats to wetland birds at Kealia Pond are predation by non-native mammals, outbreaks of avian botulism, uncontrolled and unpredictable fluctuations in water level, invasive alien plants, alien fish, and sedimentation and potential contamination from upstream agricultural sources. Predation by mongoose, feral cats, and rats is a serious threat to waterbirds and especially their nests. Predators are controlled on the refuge to protect waterbirds and creation of additional predator-free nesting habitat will help promote recovery of endangered waterbirds. Dry conditions, limited water supply, and lack of water control can limit habitat for wildlife and cause nest failure. From August-December water is pumped from wells to maintain the main pond, but input is slightly less than output by seepage and evaporation so water level declines. Outbreaks of avian botulism occur occasionally as a result of nutrient-rich sediments, high water temperature, low dissolved oxygen, and fish mortalities caused by drying of wetlands. Dead fish provide a mechanism (maggots) to transmit botulism to waterbirds. After an outbreak of botulism in October 2000, the refuge intensified efforts to monitor for dead birds and remove fish carcasses to reduce the magnitude of future outbreaks. Improved water management capabilities (water control structures, water supplies, and new wetland impoundments) will help improve habitat management and maximize the amount of habitat available at different seasons, and also help reduce botulism outbreaks. Alien tilapia breed and become numerous during winter months when the pond is full, modifying the substrate with nests. Fish die-offs occur as the water recedes, promoting outbreaks of botulism and creating a noxious odor that is carried by tradewinds to adjacent property owners. Invasive alien plant species, including pickleweed, California bulrush, primrose, and California grass, degrade wetland habitat quality by encroaching onto mudflats.


The land occupied by Kealia Pond National Wildlife Refuge is owned by Alexander and Baldwin, Inc., but the U.S. Fish and Wildlife Service has a perpetual conservation easement over 691 acres at Kealia Pond and is currently working with the landowner on the conveyance of a perpetual easement over 9-34 acres as a contiguous extension of the refuge on the Ma?alaea mudflats.


Kealia Pond National Wildlife Refuge occupies a natural basin along the south-central coast of Maui. It is 280 hectares (691 acres) in size and includes open water (approximately 81 hectares or 200 acres on average), mudflats (182 hectares or 450 acres), and adjacent upland habitat (20 hectares or 50 acres) that is dominated by alien plants. The large central pond undergoes an annual cycle of flooding in winter and drying in summer. The hydrological and biological changes associated with this cycle are important in maintaining a healthy wetland. Water depth ranges from approximately 20 cm in summer to 145 cm in winter. The variable water depth and extensive mudflats that surround the pond provide valuable foraging habitat for a variety of birds. Several small islands provide predator-free nesting habitat, and additional nesting habitat is present among shoreline vegetation that surrounds the pond.

Land Use

Kealia Pond National Wildlife Refuge was established to permanently protect and enhance wetland habitat for endangered waterbirds, primarily Hawaiian stilts and Hawaiian coots, and to provide dependable habitat for migratory wetland birds and wildlife-dependent opportunities for the public. Specific goals of the refuge are to: 1) promote conservation of endangered species, especially endangered Hawaiian stilt and Hawaiian coot, through healthy functioning of this wetland floodplain; 2) optimize water levels for maximum habitat size and value for endangered, resident, and migratory waterbirds while reducing the growth and reproduction of invasive species; 3) expand understanding, appreciation, and stewardship of wetland and coastal ecosystems through wildlife-oriented educational opportunities, visitor services, and active participation of volunteers; 4) develop community partnerships to enhance wetland and watershed habitats. In order to better understand conservation needs and improve habitat management, refuge staff also conducts research on the breeding success of Hawaiian Stilts and Coots in relation to substrate conditions, distribution and abundance of foods, water quality parameters, and pond hydrology. The Refuge is open to the public for wildlife observation throughout the year, though some areas are closed during stilt and coot nesting seasons to reduce human disturbance. Partnerships with local organizations provide educational and interpretive opportunities. The refuge has an active volunteer program for habitat restoration, wildlife monitoring, environmental education, and maintenance projects. The refuge is constructing the Kealia Coastal Boardwalk in partnership with Federal Highways Administration. This 668-meter (2,200-feet) raised boardwalk provides access along Ma?alaea flats and includes self-guided interpretive exhibits that will hopefully open in 2008.

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