Wetland Birds

Ae'o

(Hawaiian Stilt)

 Photo credit: Mike Teruya

 Fun Facts

_The ae‘o is a slender wading bird that grows up to 15 inches in length.

- Ae‘o (Hawaiian stilt) aggressively defend their nests, calling and diving at intruders and performing broken-wing displays to attract potential predators away from their nests.

- Generally three to four eggs are laid and are capable of leaving nest shortly after hatching.Chicks hatch approximately 24 days later. Both parents incubate eggs and brood young, and fledglings remain with their parents for several months.

- Stilts have a loud chirp that sounds like: kip kip kip. The female chirp is lower than the male’s.

Diet

- Ae‘o use a variety of aquatic habitats but are limited by water depth and vegetation cover. Specific water depths of 13 cm (5 inches) are required for optimal foraging.

- Stilts consume a wide variety of invertebrates and other aquatic organisms (worms, crabs, fish).

Status

-The ae‘o can still be found on all the major islands except Kaho‘olawe. Their numbers have not increased by much.

- It appears that the population has stabilized or slightly increased over the past 30 years. Stilt numbers have varied between 1,100 and 1,783 between 1997 and 2007.

- Maui and O‘ahu accounting for 60-80% of them.

- The primary causes of the decline has been the loss and degradation of wetland habitat and introduced predators (e.g., rats, dogs, cats, mongoose).

-Other factors include alien plants, introduced fish, bull frogs, disease, and sometimes environmental contaminants.

 

Alae ke'oke'o

(Hawaiian Coot)

 

Photo credit: Patty Bruno

Fun Facts

- Male and female coots look alike. This endemic bird of Hawai‘i is smaller than its mainland relatives, measuring 15 inches in length.

- ‘Alae ke‘oke‘o build floating nests in aquatic vegetation, in which four to ten eggs are laid. Adults defend their nests vigorously.

- Chicks are able to run and swim soon after hatching but maintain contact with parents by frequent calling.

- The Native Hawaiian considered ‘alae ke‘oke‘o (Hawaiian coot) to be a deity, but also considered it good to eat.

Diet

- ‘Alae ke‘oke‘o eats seeds and leaves of aquatic plants, insects, tadpoles, and small fish.

- The species will travel long distances, including between islands, when local food sources are depleted.

Status

- Between 1,000 to 2,000 ‘alae ke‘oke‘o live in all the main Hawaiian islands, except Kaho‘olawe. It is believed that the population fluctuates according to climatic and hydrological conditions.

-Maui Nui (Maui, Moloka‘i and Lana‘i) has the second largest population in the state (O‘ahu is first).

- The primary causes of the decline of this Hawaiian native water bird has been the loss and degradation of wetland habitat and introduced predators (e.g., rats, dogs, cats, mongoose). Other factors include alien plants, introduced fish, bull frogs, disease, and sometimes environmental contaminants.

 

Black Crowned Night Heron

 Photo credit: http://www.chesapeakebay.net/

Fun Fact

-They’re most active at night or at dusk.

- These social birds breed in colonies of stick nests usually built over water. They live in fresh, salt, and brackish wetlands and are the most widespread heron in the world.

- Black-crowned Night-Herons often spend their days perched on tree limbs or concealed among foliage and branches.

Diet

- Mostly fish.

-Diet quite variable; mostly fish, but also squid, crustaceans, aquatic insects, frogs, clams, mussels, rodents, carrion.

- Sometimes specializes on eggs and young birds

-Usually forages by standing still or walking slowly at edge of shallow water.

Status

-Populations have probably declined in 20th century owing to habitat loss and, in mid-century, effects of DDT and other persistent pesticides. Following the banning of DDT, many local populations have increased in recent years. Water pollution is still a problem in some areas, but overall population probably stable or increasing.

 

References and further reading

 https://www.fws.gov/pacificislands

 http://dlnr.hawaii.gov/wildlife/files

https://www.allaboutbirds.org

http://www.audubon.org/

http://www.arkive.org