Species At Risk

Black Tern

(Chlidonias niger)

Special Concern

Black Tern
Black Tern occurrences map


The Black Tern is a small, boldly marked waterbird, about 20 to 26 centimetres long, with a black head and under parts during the breeding season. Like other terns, the Black Tern has a forked tail, straight pointed bill, slender shape and long, narrow wings.

Black Terns eat mainly insects, hovering just above the water as they pick their prey off the surface.

Action we are taking:


The Black Tern breeds in the temperate regions of Europe, and in North America where it ranges from northern British Columbia and Alberta south to Arizona and Kansas and east to New Brunswick. In Ontario, Black Terns are found scattered throughout the province, but breed mainly in the marshes along the edges of the Great Lakes.


Black Terns build floating nests in loose colonies in shallow marshes, especially in cattails. In winter they migrate to the coast of northern South America.


Historical records show Black Terns were once common in Ontario, and that recent declines have been occurring since the 1980s. Threats include the draining and altering of wetlands, water pollution and human disturbance at nesting colonies – especially boat traffic, which can swamp the terns’ floating nests.


The Black Tern is listed as a species of Special Concern under Ontario’s Endangered Species Act. Although species of Special Concern do not receive legal protection under this act, this species and its nest are protected under the federal Migratory Birds Convention Act.

What You Can Do to Help the Black Tern

  • The Ministry of Natural Resources tracks species at risk such as the Black Tern. You can use a handy online form to report your sightings to the Natural Heritage Information Centre. Photographs with specific locations or mapping coordinates are always helpful. nhic.mnr.gov.on.ca
  • Report any illegal activity related to plants and wildlife to 1-877-TIPS-MNR (847-7667).
  • Private land owners have a very important role to play in species recovery. You may be eligible for stewardship programs that support the protection and recovery of species at risk and their habitats.
  • Bird Studies Canada is working to advance the understanding, appreciation and conservation of wild birds and their habitat in Ontario and elsewhere. For more information on how you can help, visit: www.bsc-eoc.org.
  • Volunteer with your local nature club or provincial park to participate in surveys or stewardship work focused on species at risk.

Did you know?

The Black Tern is very social. It breeds in loose colonies and usually forages, roosts and migrates in flocks of a few to more than 100 birds, occasionally up to tens of thousands.

Did you know?

Terns’ steady wing beats and buoyant movements have earned them the name "sea swallows".

The Endangered Species Act

Contact your local ministry office

Often the best source of local information on species at risk is your nearest ministry office. Call with your questions or concerns.