Tara tern
| Tara tern | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|
Tara tern ( Sterna striata ) |
||||||||||
| Systematics | ||||||||||
|
||||||||||
| Scientific name | ||||||||||
| Sterna striata | ||||||||||
| Gmelin , 1789 |
The Tara tern ( Sterna striata ) is a species from the tern family . It occurs exclusively in the southern hemisphere and is very similar to the sandwich tern in the northern hemisphere.
Appearance
The Tara tern reaches a height of 35 to 43 centimeters. The wing length is 26 to 28.8 centimeters and the wingspan is 79 to 82 centimeters. It weighs between 103 and 160 grams. Females tend to be slightly smaller and lighter than males.
Overall, the Tara tern looks very light, the body plumage is white and pale gray. The tail is forked deep. The legs are relatively short. The wings are long and narrow in relation to the body size. Adult Tara terns have a dark skull in their splendid dress . This dark color extends far into the back of the neck. On the forehead, a narrow white stripe separates the beak from the dark head cap, the cheeks are also whitish. The outer hand wings are noticeably darker than the rest of the wings. The underside of the body is completely white with a slight pink tinge. In the plain dress , the white forehead is somewhat more extended, the elongated tail feathers are missing in non-breeding adult Tara terns.
Distribution and existence
The Tara Tern breeds in Tasmania, the islands of the Furneaux Group , New Zealand's North Island, New Zealand's South Island as well as the Stewart Islands , the Chatham Islands and Auckland Islands . It usually resides on rocky coasts.
Way of life
The Tara tern eats fish and, to a lesser extent, shrimp that it finds in the surf zone. Occasionally she dives into the sea from a height of seven to ten meters while searching for food.
Tara terns are colony breeders. The colonies usually contain one hundred to five hundred breeding pairs. The nest is a hollow dug into the sand that is occasionally covered with grass. The clutch consists of one or two eggs. The hatched chicks are hobbled for a period of four to six days. The chicks occasionally form groups of children until they fledge at 29 to 35 days of age. However, they are dependent on the care provided by their parent birds for a period of three to six months.
Internal system
In the literature, up to three subspecies for the Tara tern are occasionally distinguished. However, the validity of this division is sometimes questioned and the Tara tern is treated as a monotypical species. The following subspecies are mentioned:
- S. s. incerta , which breeds on islands northeast of Tasmania
- S. s. striata , the nominate form found in New Zealand
- S. s. aucklandorna , which breeds in the Chatham Islands and Auckland Islands
supporting documents
literature
- Hadoram Shirihai: A Complete Guide to Antarctic Wildlife - The Birds and Marine Mammals of the Antarctic Continent and Southern Ocean. Alula Press, Degerby 2002, ISBN 951-98947-0-5 .
Single receipts
Web links
- Sterna striata inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved September 19, 2013.