Sterna paradisaeaArctic tern

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Geographic Range

Circumpolar; nests on Northern European islands and peninsulas from Iceland to Northern Russia/Siberia, British Isles, Netherlands, Denmark, Sweden, the Baltic Nations, Northern Alaska, extreme of Northern Canada, Greenland, Newfoundland, and south along Atlantic Coast to Massachussetts; winters in S. Hemisphere in subantarctic and Antarctic waters of Atlantic, Pacific, and Indian Oceans.

Habitat

All terns live along seacoasts and around interior lakes and marshes.

  • Aquatic Biomes
  • lakes and ponds
  • coastal

Physical Description

Arctic terns are 14-17''(36-43 cm) long with a wingspread of 29-33''(74-84 cm). They are white with black caps and gray mantles, and a deeply-forked tail. In spring and summer, the entire bill is blood-red. Their legs are so short that the birds appear to be crouched when standing.

  • Average mass
    100 g
    3.52 oz
    AnAge

Reproduction

They nest in colonies defended by the males in the rocky or sandy beaches of the far north. The nest usually consists of a hollow in sand, gravel or moss. In June-July, 2-3 brown or greenish eggs with brown speckles are incubated for 21-22 days. Young fly about 21-28 days after hatching

  • Average eggs per season
    2
    AnAge
  • Average time to hatching
    21 days
    AnAge

Lifespan/Longevity

Behavior

Arctic terns walk with a mouse-like glide and utter a shrill "kee-kee" or "kee-kahr". Many migrate from the Arctic summer breeding grounds to Antarctica for a "second summer", making them the animal that sees the most sun. Terns are very sociable and nest in large colonies, which are not always in the same area each year. They are vigorous in defending their nesting colonies and are most successful in breeding when they nest close together. Tern courtship is performed through a "fish flight" by the male: after much aerial chasing and screaming, the male offers a small fish to the female. They can even scream with a fish in their mouths. Most terns mate for life.

Communication and Perception

Food Habits

Arctic terns hover 30-40 feet over the water on beating wings and then dive suddenly into the water with a splash, often completely submerging to catch small fishes such as capelin, sand launae, sand eel, and small crustaceans.

Economic Importance for Humans: Positive

Once hunted for their feathers.

Conservation Status

Foxes, raccoons, weasels, rats, gulls, and other seabirds are all predators of terns and their eggs. Massive spraying of marshes with insecticides (DDT) for mosquito control has killed many terns through their consumption of DDT-laden minnows. In the last decade of the 19th century and in the first decade of the present one, plume hunters killed tens of thousands of terns for their plumage for women's hats.

Contributors

Robin Street (author), University of Michigan-Ann Arbor.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

acoustic

uses sound to communicate

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

endothermic

animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.

forest

forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.

iteroparous

offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

taiga

Coniferous or boreal forest, located in a band across northern North America, Europe, and Asia. This terrestrial biome also occurs at high elevations. Long, cold winters and short, wet summers. Few species of trees are present; these are primarily conifers that grow in dense stands with little undergrowth. Some deciduous trees also may be present.

tundra

A terrestrial biome with low, shrubby or mat-like vegetation found at extremely high latitudes or elevations, near the limit of plant growth. Soils usually subject to permafrost. Plant diversity is typically low and the growing season is short.

visual

uses sight to communicate

References

Audubon Society Encyclopedia of North American Birds; Terres; Alfred A. Knopf: New York 1980.