Black-necked stilts are black above and white below with a long neck, needle-like black bill, and long pink legs. In relation to body size, they have the longest legs compared to any other bird aside from flamingoes. 

Black-necked stilts can be 14 to 15 inches long (35 to 39 centimeters), with a wingspan of 28 to 30 inches (71 to 75 centimeters), and a weight of 5 to 6 ounces (150-176 grams). Their size is between a robin and crow.

These elegant birds use an assortment of sparsely vegetated, shallow wetlands, including mudflats, mangroves, marshes, shallow lagoons, flooded river shorelines, and salt ponds. They also use human-modified landscapes, including rice and other flooded crop fields, evaporation ponds and sewage ponds.

Black-necked stilts live approximately 20 years.

They make various sharp, high-pitched calls when communicating with and alerting others.

To defend their nests, black-necked stilts will perform a “popcorn display,” in which a group of birds surrounds the predator and individual birds hop, jump and flop to confuse and drive it away.

Their diet primarily consists of insects, small crustaceans, amphibians, tiny fish and snails. Examples include larval mosquitoes, flies, crickets, grasshoppers, beetles, crayfish, brine shrimp, tadpoles, and small frogs and fish. Seeds and plants are also known to make up a small portion of their diet. They hunt by chasing prey through shallow water or by swinging their bills side to side at the water’s surface to skim up prey. 

Loosely diurnal, stilts are most active during dawn and dusk, though they have been observed hunting at all hours of the day and night. 

They are loosely territorial, though they do breed in small colonies and roost in small groups. Their colonies consist of dozens of pairs. 

Black-necked stilts nest in loose colonies. Pairs are monogamous through the breeding season but not from year to year. However, if a pair has a nest that fails, they will sometimes try again with another mate.

Nest sites are on bare ground near the water or just above the water level, such as on small islands, algae mats, or on clumps of vegetation. Both parents help build the nest. The nests themselves are formed by making small depressions in the ground and lining them with natural materials such as grasses, mud chips, pebbles, shells and bones.  

Females lay between two and five eggs. The eggs are light brown in color with brown and black blotches. Both parents take turns incubating the eggs, which hatch after about 25 days.

When the weather gets too hot, parents soak up water with their belly feathers and fetch it back to cool their nests. They can sometimes make more than a hundred trips a day.

When predators, such as foxes, coyotes, feral cats, skunks or gulls threaten nests or young, nearby stilts will emit piercing shrieks, pretend to have broken wings or dive aggressively at the threat.

Hatchlings are covered with downy feathers and are able to leave the nest shortly after hatching, though they will not be able to fly for another four to five weeks. Both parents take care of the young.

While black-necked stilts are of low conservation concern, individuals are vulnerable to habitat destruction, degradation and wetland pollution.