Whiskered Tern
Encyclopedia
The Whiskered Tern is a seabird
of the tern
family Sternidae. This bird
has a number of geographical races, differing mainly in size and minor plumage details.
C. h. hybridus breeds in warmer parts of Europe
and Asia
. The smaller-billed and darker C. h. delalandii is found in east and south Africa
, and the paler C. h. javanicus from Java to Australia
.
The tropical forms are resident, but European and Asian birds winter
south to Africa and the Indian Subcontinent
.
This species breeds in colonies on inland marshes, sometimes amongst Black-headed Gull
s, which provide some protection. The scientific name arises from the fact that this, the largest marsh tern
, show similarities in appearance to both the white Sterna terns and to Black Tern.
The size, black cap, strong bill (29–34 mm in males, 25–27 mm and stubbier in females, with a pronounced gonys) and more positive flight recall Common
or Arctic Tern
, but the short, forked-looking tail and dark grey breeding plumage above and below are typically marsh tern characteristics. The summer adult has white cheeks and red legs and bill. The crown is flecked with white in the juvenile, and the hindcrown is more uniformly blackish, though in the winter adult this too is flecked with white. The black ear-coverts are joined to the black of the hindcrown, and the space above is mottled with white, causing the black to appear as a C-shaped band. The sides of the neck are white; this sometimes continues across the nape. The collar is less sharply defined. All through the year the rump is pale grey. In the juvenile, the mantle (279 mm) has a variegated pattern. The feathers of the back and scapulars are dark brown, with prominent broad buff edgings and often subterminal buff bars or centers. There is usually an admixture of new gray feathers, especially on the mantle, quite early in the fall. The mantle is silvery-gray in the adult.
The call is a characteristic krekk.
In winter, the forehead becomes white and the body plumage a much paler grey. Juvenile Whiskered Terns have a ginger scaly back, and otherwise look much like winter adults. The first winter plumage is intermediate between juvenile and adult winter, with patchy ginger on the back.
The Whiskered tern eats small fish, amphibians, insects and crustaceans.
Seabird
Seabirds are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations...
of the tern
Tern
Terns are seabirds in the family Sternidae, previously considered a subfamily of the gull family Laridae . They form a lineage with the gulls and skimmers which in turn is related to skuas and auks...
family Sternidae. This bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
has a number of geographical races, differing mainly in size and minor plumage details.
C. h. hybridus breeds in warmer parts of Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
. The smaller-billed and darker C. h. delalandii is found in east and south Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...
, and the paler C. h. javanicus from Java to Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
.
The tropical forms are resident, but European and Asian birds winter
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
south to Africa and the Indian Subcontinent
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...
.
This species breeds in colonies on inland marshes, sometimes amongst Black-headed Gull
Black-headed Gull
The Black-headed Gull is a small gull which breeds in much of Europe and Asia, and also in coastal eastern Canada. Most of the population is migratory, wintering further south, but some birds in the milder westernmost areas of Europe are resident...
s, which provide some protection. The scientific name arises from the fact that this, the largest marsh tern
Marsh tern
The name marsh tern refers to terns of the genus Chlidonias, which are typically found in freshwater marshes, rather than coastal locations.There are four species:* Black Tern, Chlidonias niger...
, show similarities in appearance to both the white Sterna terns and to Black Tern.
Description
Common Tern
The Common Tern is a seabird of the tern family Sternidae. This bird has a circumpolar distribution, breeding in temperate and sub-Arctic regions of Europe, Asia and east and central North America. It is strongly migratory, wintering in coastal tropical and subtropical regions. It is sometimes...
or Arctic Tern
Arctic Tern
The Arctic Tern is a seabird of the tern family Sternidae. This bird has a circumpolar breeding distribution covering the Arctic and sub-Arctic regions of Europe, Asia, and North America...
, but the short, forked-looking tail and dark grey breeding plumage above and below are typically marsh tern characteristics. The summer adult has white cheeks and red legs and bill. The crown is flecked with white in the juvenile, and the hindcrown is more uniformly blackish, though in the winter adult this too is flecked with white. The black ear-coverts are joined to the black of the hindcrown, and the space above is mottled with white, causing the black to appear as a C-shaped band. The sides of the neck are white; this sometimes continues across the nape. The collar is less sharply defined. All through the year the rump is pale grey. In the juvenile, the mantle (279 mm) has a variegated pattern. The feathers of the back and scapulars are dark brown, with prominent broad buff edgings and often subterminal buff bars or centers. There is usually an admixture of new gray feathers, especially on the mantle, quite early in the fall. The mantle is silvery-gray in the adult.
The call is a characteristic krekk.
In winter, the forehead becomes white and the body plumage a much paler grey. Juvenile Whiskered Terns have a ginger scaly back, and otherwise look much like winter adults. The first winter plumage is intermediate between juvenile and adult winter, with patchy ginger on the back.
The Whiskered tern eats small fish, amphibians, insects and crustaceans.