Black Tern

The Black Tern (Chlidonias niger niger) is a small tern generally found in or near inland water in Europe, Western Asia and North America. As its name suggests, it has predominantly dark plumage. In some lights it can appear blue in the breeding season, hence the old English name "blue darr".

Etymology

The word tern via an East Anglian dialect, from some Scandinavian (North Germanic) language, related to Danish terne, Norwegian terne, and Swedish tärna, all from Old Norse þerna (“tern; maidservant”), ultimately from Proto-West Germanic *þewernā (“handmaid, young girl”). First attested in the 1670s.

Singular: tern
Plural: terns

The genus name is from Ancient Greek χελιδονιος / khelidonios, "swallow-like", from χελιδον / khelidon, "swallow": another old English name for the black tern is "carr (i.e. lake) swallow". The species name is from Latin niger "shining black".

Physical Appearance

The bill is long, slender, and looks slightly decurved. They have a dark grey back, with a white forewing, black head, neck (occasionally suffused with grey in the adult) and belly, black or blackish-brown cap (which unites in color with the ear coverts, forming an almost complete hood), and a light brownish-grey, 'square' tail.

The face is white. There is a big dark triangular patch in front of the eye, and a broadish white collar in juveniles. There are greyish-brown smudges on the ides of the white breast, a downwards extension of the plumage of the upperparts.

These marks vary in size and are not conspicuous. In non-breeding plumage, most of the black, apart from the cap, is replaced by grey. The plumage of the upperparts is drab, with pale feather-edgings. The rump is brownish-grey.

Abilities

The black tern's flying is quick and agile, like a swallow. Adults and chicks of terns can swim short distances if needed, but they are not as good swimmers as diving ducks. The primary vocalizations of terns are sharp, high-pitched sounds made while flying or in colonies (typical for terns on the water's surface).

Black terns have the ability to spit out a black substance that, when sprayed on prey, can quickly cause blindness or horror. It is believed that this skill developed because of a need to raise the percentage of prey that can be caught in order to supply enough food for a pack before or after the migration. When compared to other tern species, the black tern's spit was significantly different.

Ecology

As carnivores, black terns forage over marshes and bodies of water. Small fish and aquatic invertebrates (insects and crustaceans) make up their primary diet. Unlike some coastal terns, they frequently hover low over the water, snatching prey off the surface. They engaged in both fishing and flying bug hawking.

Reproduction

Nesting: In loose colonies in shallow freshwater marshes; nests usually built on floating vegetation or very close to water.
Clutch: Typically lays 2–4 eggs; incubation ~3 weeks.
Chick behavior: Young may leave the nest and hide among vegetation at the first sign of danger.

Behavior

One of the most combative terns, it is ferociously protective of its nest & young. It will strike the top as well as the side of the head once assaulting people and dangerous animals. Although it is too small to seriously harm an animal the length of a human, it can still draw blood and deter many raptorial birds, polar bears, and other smaller mammalian predators like foxes and cats.

Threats and Conservation

Threats

Wetland loss from drainage & agriculture.
Population declines in parts of North America (e.g., New York state Endangered).
Local extirpations where prime marsh habitat was destroyed (e.g., Hula Lake, Israel).

Conservation Status

IUCN Red List: Least Concern (LC)

Conservation Efforts

Conservation actions include wetland protection and migratory bird agreements such as AEWA.

Habitat protection.
Anti-poaching enforcement.
Rescue and rehabilitation centers.
Awareness campaigns against illegal pet trade.

Distribution and Habitat

Their breeding habitat is freshwater marshes across most of Canada, the northern United States and much of Europe and western Asia. They usually nest either on floating material in a marsh or on the ground very close to water, laying 2–4 eggs.

Movement Pattern: Full Migrant
Individual Type: Gather
Population Trend: Increasing
Population: ???
Locomotion: Versatile
Habitat: Taiga; Montane Grasslands and Shrublands; Temperate Coniferous Forests; Temperate Broadleaf and Mixed Forests; Temperate Deciduous Forests; Temperate Grasslands, Savannas, and Shrublands; Subtropical Coniferous Forests; Subtropical Moist Broadleaf Forests; Subtropical Dry Broadleaf Forests; Subtropical Grasslands, Savannas, and Shrublands; Salt Flats; Stone Forest; Tropical Coniferous Forests; Tropical Moist Broadleaf Forests; Tropical Dry Broadleaf Forests; Tropical Grasslands; Tropical Savannas and Shrublands; Mediterranean Forests, Woodlands, and Scrub; Mushroom Forests; Mushroom Fields; Deserts and Xeric Shrublands; Badlands; Flooded Grasslands and Savannas; Swamp; Bayous/Billabongs; Riparian; Wetland; Mangrove Forest; Cold Bamboo Forests; Tropical Bamboo Forests; Air-breathing Coral Reefs; Graveyard Vale; Mountain; Sky; Warm River; Cold River; Lukewarm River; Warm Littoral; Cold Littoral; Warm Intertidal; Cold Intertidal; Radiated Citadel; Volcano; Warm Ghost Town; Cold Ghost Town; Ruined Skyscraper.
Earth: see below
- Extant (Resident): Albania; Algeria; Angola; Anguilla; Antigua and Barbuda; Argentina; Aruba; Bahamas; Barbados; Belgium; Belize; Benin; Bermuda; Brazil; Cameroon; Cayman Islands; Chile; China; Colombia; Congo; Costa Rica; Croatia; Cuba; Cyprus; Côte d'Ivoire; Denmark; Djibouti; Dominica; Dominican Republic; Ecuador; Egypt; El Salvador; Equatorial Guinea; Eritrea; Ethiopia; France; French Guiana; Gabon; Gambia; Germany; Ghana; Greece; Guatemala; Guinea; Guinea-Bissau; Guyana; Haiti; Honduras; Hungary; India; Ireland; Israel; Italy; Liberia; Libya; Liechtenstein; Luxembourg; Mali; Malta; Martinique; Mauritania; Mexico; Montserrat; Morocco; Namibia; Netherlands; Nicaragua; Nigeria; Panama; Peru; Poland; Puerto Rico; Romania; Russia (Central Asian Russia, European Russia); Saint Kitts and Nevis; Saint Lucia; Saint Pierre and Miquelon; Saint Vincent and the Grenadines; Sierra Leone; Slovakia; Slovenia; South Africa; Spain; Sri Lanka; Suriname; Sweden; Switzerland; Tajikistan; Tanzania; Togo; Trinidad and Tobago; Tunisia; Turks and Caicos Islands; Türkiye; Ukraine; Uzbekistan; Venezuela, Bolivarian Republic of; Western Sahara
- Extant (Breeding): Armenia; Azerbaijan; Belarus; Bosnia and Herzegovina; Bulgaria; Canada; Czechia; Estonia; Finland; Georgia; Kazakhstan; Kyrgyzstan; Latvia; Lithuania; Moldova; Mongolia; Montenegro; North Macedonia; Portugal; Russia (Eastern Asian Russia); Serbia; United Kingdom; United States
- Extant (Non-breeding): Jamaica
- Extant (Passage): Austria; Gibraltar; Iran; Jordan; Palestine; Senegal; Syria; Turkmenistan
- Extant & Vagrant (Breeding): Iceland
- Extant & Vagrant (Non-breeding): Guadeloupe
- Extant & Vagrant (Passage): Bahrain; Iraq; Kuwait; Lebanon; Oman; Saudi Arabia; Sudan; Yemen
- Extant & Vagrant (Seasonality Uncertain): Uruguay
- Extant & Vagrant: Afghanistan; Australia; Chad; DR Congo; Grenada; Japan; Kenya; Madagascar; Niger; Rwanda; Somalia; United Arab Emirates; Virgin Islands, British; Virgin Islands, U.S.
- Extant & Origin Uncertain (Seasonality Uncertain): Sao Tome and Principe