White-winged day sleeper
| White-winged day sleeper | ||||||||||
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Male white-winged day sleeper ( Nyctibius leucopterus ) |
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| Nyctibius leucopterus | ||||||||||
| ( Wied , 1821) |
The white-winged day sleeper ( Nyctibius leucopterus ) is a nocturnal species of bird belonging to the day sleeper genus . The so far little researched species inhabits the tropical forests in South America and was first scientifically described in 1821 by the German naturalist Maximilian zu Wied-Neuwied .
Description and behavior
description
When fully grown, the white-winged day sleeper reaches a size of around 24 to 29 cm with a weight of around 77 to 85 g. This makes it a rather small representative of its genus. Body and head have a squat, rounded appearance, the large eyes with yellow irises , which are adapted to the nocturnal lifestyle, and the broad, pointed beak are striking . The tail is rather short for a day sleeper. The plumage of the animals is grayish-brown on the upper side and interspersed with black and brown stripes, which continue to the belly and chest. The throat and chin tend to turn grayish white. On the shoulders of the male there is a characteristic white spot that gave the species its name. This tends to be somewhat smaller and less pronounced in females, but there are no other visual distinguishing features between the sexes. Overall, their coloring gives the birds a well-functioning camouflage pattern that makes them look like part of their environment during the daytime hours.
Behavior and nutrition
The white wing day sleeper is probably the least well researched day sleeper. Like all day sleepers, it rests almost motionless on a branch or tree stump during the day. During the night, the birds wait for potential prey in a waiting room , which they pounce on with one quick movement and catch with their broad beak. The diet consists of various insects such as moths , fishing rods , flying termites , grasshoppers and beetles . White-winged day sleepers lead a largely solitary way of life outside of the breeding season , and they are all resident birds .
Reproduction
The breeding season and the duration of brood care are unknown. A nest is not built, instead the female lays a single egg in a recess on a branch or on the top of a broken tree stump. The birds are monogamous and both adults participate in the rearing of the offspring. After hatching, the parents sit upright on the young bird, which hides between its breast feathers in case of danger. The young are fed exclusively at night. They leave the nesting site when they are about two-thirds the size of their parents and have fledged. Even after that, however, they are still dependent on the care of the adult birds for a certain time.
Vocalizations
The most common song of the white-winged day sleeper is described as a plaintive, haunting sound that is supposed to sound something like weuuuuuu . Another sound uttered , especially in flight or to contact conspecifics, corresponds to a whistling hweep , which is often repeated several times in quick succession. The birds sing especially during the night hours when they are more active. Furthermore, they can be heard particularly often on nights with strong moonlight.
Spread and endangerment
The white-winged day sleeper inhabits tropical, evergreen forests on the South American continent, although it seems to prefer primary forest undisturbed by humans . Here it can be detected up to heights of about 900 m. The main range of the species includes the Amazon basin in the countries of Brazil , Venezuela , Peru and the Guyanas . Another isolated population can be found in southeastern Brazil on the Atlantic coast. The type specimen on the basis of which zu Wied-Neuwied originally described the species in 1821 came from here . It was not until 1999 that further evidence of a white-winged day dormouse from southeastern Brazil was found in the area of the Una Biological Reserve in the south of the state of Bahia . The birds are generally considered to be rather rare and are not seen often, which could be at least partly due to their good camouflage and inactivity during the day. The IUCN classifies the white wing Tagschläfer with stand 2016 as not endangered (status least concern ) one, for which mainly the geographically large area of distribution is used. At the same time, however, the organization notes a general decline in population numbers. The greatest threat to the conservation of the species is the deforestation, in particular the status of the population on the Brazilian south-east coast is unclear, as the rainforest there is only available in small remnants.
Systematics
The species is currently considered monotypical . Phylogenetic studies and protein analyzes of the two species indicate that the white-winged day dormouse and the Andean day dormouse ( Nyctibius maculosus ) are most likely sister species. Clear morphological and geographical differences, however, speak against a conspecificity , which is why both continue to be listed as separate species.
literature
- Nigel Cleere, Dave Nurney: Nightjars - A Guide to Nightjars and related Nightbirds . Pica Press, Susex 1998, ISBN 978-1-873403-48-8 ( limited preview in Google book search). See Chapter 20: White-winged potoo (Nyctibius leucopterus)
- Josep del Hoyo, Andrew Elliott, Jordi Sargatal : Barn-owls to hummingbirds . In: Handbook of the Birds of the World . tape 5 . Lynx Edicions, 1999, ISBN 978-84-87334-25-2 , pp. 289-294 .
Web links
- Audio recordings of utterances at xeno-canto.org
- Photos and audio recordings at ebird.org (English)
Individual evidence
- ^ Bret M. Whitney, José Fernando Pacheco, Luís Fábio Silveira, Rudi R. Laps: Rediscovery of Nyctibius leucopterus (White-winged Potoo) in the Atlantic Forest of Brazil . In: Revista Brasileira de Ornitologia . tape 11 , no. 1 , 2003, p. 1-4 .
- ↑ White-winged Potoo Nyctibius leucopterus. In: iucnredlist.org. BirdLife International, 2016, accessed November 26, 2019 .
- ↑ Thomas S. Schulenberg, Guy M. Kirwan: Andean Potoo Nyctibius maculosus - Systematics. In: cornell.edu. Cornell Lab of Ornithology, 2012, accessed November 26, 2019 .