Desert sparrow
| Desert sparrow | ||||||||||||
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Desert Sparrow ( Passer simplex ) |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Passer simplex | ||||||||||||
| ( Lichtenstein , 1823) |
The desert sparrow ( registration simplex ) is a bird art of the generic register from the family of sparrows (Passeridae). It occurs exclusively in desert regions of Africa as well as Turkmenistan and Uzbekistan. The number of subspecies is controversial. Some authors differentiate between three subspecies - two African and one Asian - others do not consider a division into subspecies to be justified, despite regional differences in appearance. Occasionally, however, the Asian populations are even viewed as a separate species of Passer zarudnyi .
The IUCN classifies the desert sparrow as not endangered ( least concern ).
Appearance
Desert sparrows reach a body length of 13 to 14 centimeters. There is a pronounced sexual dimorphism .
The males forehead, upper head and back are light ash-colored, the rump and the upper tail-coverts are pale cream-colored. The control feathers are dark gray-brown with cream-colored edges. The bridle of the eye and a short stripe behind the eyes are black-brown, the cheeks, the ear covers and the sides of the neck are creamy-white. The chin and throat are black, the rest of the underside of the body is white. The sides of the chest are washed out with gray-pink, the flanks cream-colored. The beak is horn-colored with a yellowish lower bill, it becomes darker during the breeding season. The eyes are brown, the legs pale brown.
The females have no conspicuous color markings on their heads. They are light cinnamon-colored on the upper side of the body, the control feathers are colored like the male. The cheeks and the ear covers are isabel-colored, the chin and throat are creamy white. The rest of the underside of the body is yellowish-white, the chest and flanks are overlaid with a light cinnamon color. Fledglings resemble females, but the tail feathers are a little paler.
Distribution area
The desert sparrow occurs in Africa north of the 15th parallel north. It also belongs to the avifauna of Turkmenistan and Uzbekistan. It is currently not clear whether there are still populations in the area of Iran.
The distribution area is not contiguous. The desert sparrow is generally a nomadic species. It is sometimes common in some regions, then rare or even absent completely. Presumably, the population figures are currently falling in Morocco and Algeria; it is sometimes no longer observed here in regions where it used to be frequent. Most populations are resident birds, but some sparrow populations migrate south during the winter months. This is probably less a matter of targeted train movements than an undirected nomadization in order to open up new food grounds.
habitat
The habitats of the desert sparrow are dry wadis and oases in sandy regions with a sparse population of trees and bushes. Typical plants in its range are Tamarix articulata , date palms , Raetama raetam , Colligonium comosum , Aristida pungens , caper bushes and acacias . The desert sparrow, on the other hand, shuns open desert. It also occurs on the outskirts of settlements. It lives mainly in plains and only occurs regionally in hilly landscapes.
Way of life
The desert sparrow usually occurs in pairs or in small groups of up to ten individuals; larger groups are only observed in regions with good living conditions for this species. In the winter months, troops with 80 and in Algeria troops with 150 to 200 individuals were counted in Tunisia. Compared to most other sparrow species, it is less sociable. The desert sparrow is shy and rarely lets out vocalizations.
The desert sparrow finds its food mainly on the ground. It mainly eats seeds from various desert plants, with seeds of the grass genus Aristida as well as millet and various types of barley playing a special role. It also eats caterpillars, beetles and their larvae, as well as spiders, and also looks for food in household waste. Compared to the house sparrow, the digestive tract is smaller in proportion to its size, which is taken as an indication that animal food plays a greater role in this species than in the house sparrow.
Reproduction
Desert sparrows nest either individually or in small colonies. Such colonies are often found in the nesting grounds of large birds such as the black vulture or the lappet vulture , in tree hollows or in the crown of date palms .
The nest is between 13.6 and 25.0 inches long and 13.5 to 18.0 inches high. The nest ball has a side entrance that has a diameter of 3.2 to 5.0 centimeters. Apart from the nesting locations mentioned above, the nest is mostly built in branches of a tree that are close together. Stone walls, houses, wells and stone pyramids are also used as nesting sites. The nest is usually between 1.5 and 9.0 centimeters above the ground and is oriented so that it is protected from direct sunlight.
The clutch comprises between two and five eggs; four to five eggs are typical in years with a sufficient food base, whereas two to three eggs are typical in dry and therefore nutrient-poor years. The eggs are laid one day apart. They are elliptical with a smooth and slightly shiny white shell that has brown and purple-gray spots and scribbles. Desert sparrows often breed twice a year. In Libya, for example, they reproduce from March to June and from October to November. In Mauritania they breed from January to May and a second time in July.
So far, reproductive biology has only been studied in more detail in Asian populations of the desert sparrow. There the two parent birds start brooding after the first egg has been deposited, and the nestlings hatch accordingly over a period of up to five days. The breeding season is 12 to 13 days, the female has a significantly higher percentage of the breeding season than the male. Due to the high outside temperatures during the day, the eggs are occasionally not incubated during the day.
The nestlings already have almost complete plumage when they are seven to ten days old. Both parents are involved in the rearing, and in desert sparrows observed in Africa, the male feeds more frequently than the female. In Asian populations, no sex-dependent difference in the feeding behavior of the parent birds has been found. The young birds are mainly fed with insects and pre-digested Aristida seeds. The nestlings fledge after 12 to 14 days. Likewise, only data from Asia are available on the reproduction rate. There nestlings hatched from 44 percent of the eggs. Of the nestlings, 76 percent survived until they fledged.
literature
- C. Hilary Fry and Stuart Keith (Eds.): The Birds of Africa. Volume 7, Christopher Helm, London 2004, ISBN 0-7136-6531-9 .
