Why least tern endangered

Least terns may also nest near sand and gravel pits where sand piles from mining operations provide suitable nesting habitat. The birds typically forage in bays, lagoons, estuaries, rivers and lakes along the coast. Least terns eat small fish and occasionally shrimp and other marine invertebrates.

They hover above the water then plunge from 3 to 10 ft. They grasp the prey with their bill and are usually eaten in flight. In late April to early May terns return to coastal nesting areas in New Jersey.

They are often heard than seen while calling over and around coastal nesting areas. Courtship and colony establishment begins in the first week of May. Male terns call with fish in their bill while being pursued by other males or females. Males often perch and offer food to female terns. They nest in shallow scrapes that are made by both the male and female.

They sit in the sand and kick their feet backward while rotating to make a shallow bowl-like depression in the sand. They may make several scrapes, but they only use one. The female selects the scrape and from mid to late June she lays two to three sand-colored eggs. Forages by flying over water, hovering, and plunging to catch prey just below water's surface. Sometimes dips down to take prey from surface of water or land, and may catch insects in flight.

Buff to pale green, blotched with black, brown, gray. Incubation is by both sexes; female may do more in early stages, male more later. In very hot weather, adult may dip into water and wet belly feathers to cool eggs. Incubation period days. Young: Leave nest a few days after hatching, find places to hide nearby.

Both parents feed young. Age at first flight about days; young may remain with parents another months. One brood per year, sometimes two in south. Leave nest a few days after hatching, find places to hide nearby.

Fish, crustaceans, insects. Diet varies with season and location; mostly small fish, crustaceans, and insects, also some small mollusks and marine worms. Nests in colonies, sometimes in isolated pairs. In courtship, male carrying fish in bill flies upward, followed by female, then both glide down.

On ground, displays include courtship feeding. Nest site is on open ground or on gravel roof. Nest is shallow scrape, sometimes lined with pebbles, grass, debris. Interior least terns are the smallest of North American terns. Least terns in the interior population prefer nesting on open sandbars near wide river channels. Before the species was protected as endangered in , the number of interior least terns had plummeted below 2, birds due to changes to river systems from dams, dikes, reservoirs and water diversions, which eliminated most of their historic nesting habitat.

Natural wide channels dotted with sandbars have been replaced by narrow, armor-banked rivers with highly altered flows. The least tern faces many threats as the human population increases along the coasts.

The main threat to the least tern population is habitat loss. Loss of habitat is often attributed to coastal development. Coastal development causes damage to least tern habitat because of the building on the coasts, human traffic on the beaches, and recreational activities. Increased numbers of predators due to the larger amounts of available food and trash for scavenging are also a threat to the least tern.

Predators can cause destruction to breeding colonies while they are nesting by destroying nests and eating chicks and eggs. Also, global climate change is an impending threat to the least tern.

Rising sea levels and more frequent strong storms may damage and destroy least tern nests, as well as habitat. Spring tides can also cause flooding of least tern nests. Other threats to the least tern include shoreline hardening, mechanical raking, oil spills, response to oil spill events, and increased presence of domestic animals Defeo et al. The least tern is protected by the U. Migratory Bird Treaty Act. BirdLife International.

Sterna antillarum. In: IUCN Version Available online at iucnredlist. Defeo, O. McLachlan, D.