Rostkehl dipper
| Rostkehl dipper | ||||||||||||
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Rostkehl dipper ( Cinclus schulzii ) |
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| Cinclus schulzii | ||||||||||||
| ( Cabanis , 1882) |
The Rostkehl dipper ( Cinclus schulzii , protonym: Cinclus schulzi ) is a South American representative of the dipper . It occurs only in a very limited area in southern Bolivia and northern Argentina, where it breeds in oxygen-rich, clear watercourses. The species is monotypical . It is the sister species of the white-headed dipper ( Cinclus leucocephalus ), but is also considered by some authors as a subspecies.
description
The Rostkehl dipper is the smallest member of the Cinclidae. Your body length is about 14-15 centimeters. It is unmistakable in its area of distribution. As with all dippers, the large head is only slightly separated from the body, the body is compact and rounded and the tail, which is often stilted, is very short. The lead-gray legs and equally colored toes are long and strong. The iris is brown-black, the beak dark slate-gray.
The Rostkehl dipper is largely colored uniformly mouse gray. The most noticeable characteristic is the orange-brown throat. The bases of the hand wings are pure white on the inside, rather washed-out white on the outside. When the wing is put on, this coloring feature cannot be seen. The Rostkehl dipper, however, constantly twitches its wings and spreads the wings of the hand so that this bright window gets a clear signal effect.
Young birds are already very similar in color to the adults ; the most certain distinguishing feature is their pink beak.
distribution and habitat
The Rostkehl dipper is only found in a small area on the eastern slope of the Andes in southern Bolivia and northern Argentina . In Argentina it occurs in suitable habitats in the provinces Jujuy , Salta , Catamarca and Tucumán , in Bolivia in the Tarija department . The breeding areas of the white-headed dipper and the Rostkehl dipper are clearly separated from each other.
There it breeds along fast-flowing, clear mountain streams and smaller rivers, primarily in the altitude range between 1400 and 2500 meters dominated by alder . Some, largely isolated populations live in the distribution area; in between there are gaps in which the species does not appear despite apparently suitable living conditions. In some areas it can be quite common. Under favorable conditions, 650–1250 meters of river meters are sufficient as a habitat.
As long as the waters do not freeze over, the Rostkehl dipper remains in its breeding area; otherwise it migrates to lower areas.
Food and subsistence
Like all dippers, the Rostkehl dipper feeds exclusively on carnivore . Their diet consists primarily of invertebrates that live aquatic or occur on stones and rocks, in the flushing fringes along the edges of the water or in the bank vegetation. However, there is no detailed information on food composition.
The prey animals are mainly picked up from rocks and stones, from the water surface or the bank vegetation or wading in very shallow water. Whether the Rostkehl dipper also swims and dives is controversial; These behaviors have rarely, if ever, been observed.
behavior
In contrast to all other dippers, the Rostkehl dipper does not seem to buckle, i.e. briefly buckle in the heel joints in quick succession. Instead, she twitches her wings, presenting the bright window at the base of the wings.
Breeding biology
There is very little information on breeding biology. The few nests that have been described were in rock niches, but also on bridges, always in the immediate vicinity of the water, about half a meter to a little over a meter above the water level. The nest itself is a typical multi-layered, spherical dipper construction with an outer shell made primarily of moss and grass stalks and an inner bowl made of leaves and various fine materials.
The main season should be between late October and the end of December. The clutch usually consists of two shiny white eggs. No information is available about the breeding and nestling periods.
Systematics
The Rostkehl dipper is one of the five species of the genus Cinclus within the family Cinclidae; Occasionally this is also understood as a subfamily (Cinclinae) of the flycatcher (Muscicapidae). Two species are in Eurasia, one is in North America and two are native to South America. The relationship of the family is the subject of research. In the past, due to morphological and behavioral similarities, they were placed near the wrens (Troglodytidae), today they are more likely to be more closely related to the thrushes (Turdidae) and mockingbirds (Mimidae).
No subspecies are recognized. Considerations that regard the species as a subspecies of the white-headed dipper are not considered plausible; they are more likely to be sister species.
Inventory and inventory development
There are no current inventory figures or assessments of inventory development. According to the IUCN , the species is endangered due to its small range, the fragmented and partly isolated subpopulations and the regionally shrinking populations. Estimates assume a total population of around 1000 to a maximum of 2000 breeding pairs. The total range of this species is only about 30,000 square kilometers. Within this region there is only a single protection zone on the border with Bolivia in the province of Salta . The remaining areas are mainly threatened by logging and the intensification of animal husbandry. The Rostkehl dipper reacts very sensitively to a deterioration in their living conditions and then quickly disappears from traditional breeding waters.
literature
- David Brewer and Barry Kent MacKay: Wrens, Dippers and Thrashers . Yale University Press New Haven and London 2001; P. 19; 62-63; and 206-207, ISBN 0-300-09059-5 .
Individual evidence
- ↑ a b c Brewer (2001) p. 207
- ↑ Brewer (2001) p. 19
- ↑ Brewer (2001) p. 206
- ^ Gary Voelker: Molecular phylogenetics and the historical biogeography of dippers (Cinclus) . Ibis; Volume 144, Issue 4, pp. 577-584
- ↑ Cinclus schulzii in the Red List of Threatened Species of the IUCN 2011. Posted by: BirdLife International, 2008. Accessed November 17, 2011th
Web links
- http://tierstimmen.org/de/node/3402
- https://avibase.bsc-eoc.org/species.jsp?lang=DE&avibaseid=2135780F5304EAC1
- https://www.iucnredlist.org/species/22708169/111053629 (en)
- https://www.hbw.com/species/rufous-throated-dipper-cinclus-schulzii (en)