High altitude runner
| High altitude runner | ||||||||
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Andean high altitude runner ( At.gayi ) |
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| Systematics | ||||||||
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| Scientific name | ||||||||
| Thinocoridae | ||||||||
| Gray , 1845 |
The high altitude runners (Thinocoridae), also called sand runners , are a small family in the order of the plover-like (Charadriiformes). The family includes four species in two genera.
features
High altitude runners are quail-like, their small head is carried by a short, thin neck. The short but strong legs are similar to a chicken and start in the middle of the body. They have four toes that touch the ground, the back is severely receded. The forehead of the birds is very high, so it seems as if their eyes are far back. The beak is similar to a chicken or finch , the lower jaw is slightly thicker than the upper jaw and has a small throat dewlap. The nostrils can be closed by skin covers, they serve as protection from dust and sand. The birds have a digestive system like chicken birds : the food is pre-digested in the spacious crop , in the gizzard it is finally broken up with the help of swallowed stones. High-altitude runners have long appendixes to break down the cellulose contained in their food . Altitude runners grow to be 19 to 30 cm tall and weigh 100 to 300 grams.
High-altitude runners are densely feathered to protect against radiation. The tail is short and spatulate, the wings pointed and long. The plumage is brownish on the upper side of the trunk with a scale pattern, on the underside it is white to gray. The chest, neck, and head are usually one color, either gray or light brown. With this color they are well camouflaged in their habitat. The legs are gray, brown or orange, the beak is light gray. The Thinocorus species have a light throat that is enclosed by a black band. The birds' eyes are black.
Way of life
behavior
The high-altitude runner species living in the south migrate north in autumn, the birds from the higher altitudes migrate down the mountains. If they are threatened, they crouch or stretch themselves on the grass and rely on their camouflage color. Some species only fly away when the enemy is directly in front of them, accompanied by a chirping glü glü glü . However, high-altitude runners are bad fliers, and so after a short flight they land again and run away, tripping. Their zigzag flight is reminiscent of that of the snipe birds . The birds are sociable, they live together in groups of 10 to 20 animals even during the breeding season. The dwarf high-altitude runners are the most social birds in the family.
Nutrition and reproduction
High altitude runners have specialized in plant-based food. They eat all kinds of seeds, buds and leaves (are plucked from small plants), and they look for them on the ground and in the undergrowth. The birds often ingest small stones, they also chop up the food in the gizzard.
Not much is known about the courtship of high altitude runners, all we know is that the males perform courtship flights. From August to January the female lays four, rarely two or three eggs in a self-scratched or already existing hollow, which is enclosed by sticks and padded with moss and grass. The eggs are pear-shaped so they cannot roll away and have dark spots on an ocher-colored background. The young are light gray or beige with black spots and leave the nest immediately after hatching (they are fleeing nest ).
The clutch of the Flecken high-altitude runner was only discovered in 1959. Four eggs lay open in a nest padded with plant parts. The clutch of the dwarf high-altitude runner was probably the first to be described, CF Belcher discovered and described it. For a long time he could not find the nest in the breeding area of only a few square meters; when he went to the nesting site again, he saw no brooding bird:
“ She's not back yet, I thought, but suddenly she hissed out from under my feet and ran away. She must have slept there because I saw no nest. But there was a ring of twigs - and a small hollow. A nest started? Was she about to lay? But why had she been to that empty saucer of a nest so often before? Suddenly a thought occurred to me and I began to scrape away the dry loose earth in the middle of the nest hollow - and right, there were four eggs that had previously been completely covered, exposed before my eye ... as far as I know, the first clutch of this kind, that a human or at least an oologist had ever seen. "
It was later confirmed that when leaving the nest, this species covered the same with earth, sand or grass.
distribution and habitat
There are high altitude runners in the Andes of South America. They occur from Colombia and Ecuador through Peru and Chile to southern Argentina and Tierra del Fuego . They prefer higher areas of the mountain range, often over 5000 meters. You always stay on the snow line and hike with it. The pygmy mountain runner is also found in the deserts and steppes of the west coast ( Atacama desert ).
Systematics
This family belongs to the avifauna of South America and probably no longer have any close relatives. Fossil remains of the family or similar families are not known. This makes the relationships in the order of the plover-like species even more unclear.
The four species are divided into two genera:
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Attagis
- Andean high-altitude runners or cordilleras ( Attagis gayi ), Ecuador to southern Chile and southern Argentina
- Patch high -altitude runner or magellar runner ( Attagis malouinus ), southern Chile and southern Argentina to Tierra del Fuego
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Thinocorus
- Gray-throated high-altitude runner ( Thinocorus orbignyianus ), Peru to Tierra del Fuego
- Dwarf height runners ( Thinocorus rumicivorus ), Ecuador to northern Chile
literature
- Bernhard Grzimek: Grzimeks animal life. Deutscher Taschenbuch Verlag GmbH & Co.KG, Munich 1968, ISBN 3-423-05970-2
- Dr. Theo Jahn: Brehm's new animal encyclopedia. Verlag Herder KG, Freiburg im Breisgau Special edition for Prisma Verlag GmbH, Gütersloh 1982, ISBN 3-570-08606-2
- Joseph Forshaw: Encyclopedia of Birds. Weltbild Verlag GmbH, Augsburg 1999, ISBN 3-8289-1557-4
