Red-necked swift
| Red-necked swift | ||||||||||
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Male Red-necked Swift at Asa Wright Nature Center , Trinidad |
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| Streptoprocne rutila | ||||||||||
| ( Vieillot , 1817) |
The red-necked swift ( Streptoprocne rutila , Syn .: Cypseloides rutilus ) is a species of bird from the family of sailors (Apodidae). The plumage is predominantly black-brown. However, it has a strongly contrasting red collar, so the Red-necked Swift is the only sailor with a slightly more conspicuous color, along with its sister species , the Phelpssegler . With a body length of 13 centimeters, the Red-necked Swift is quite small, it is the smallest representative of the genus Streptoprocne .
The range is very fragmented and limited to Central and South America. There the red-necked swift occurs predominantly in the Cordilleras and adjacent mountains. The nests are built on vertical structures. The nesting sites are typically close to water, for example in narrow, damp ravines or near waterfalls.
features
Appearance
The body length is approximately 13 centimeters. For the wing length values between 116.0 and 130.5 millimeters were determined in males, and between 112.0 and 124.5 millimeters in females. The weight is around 21 grams.
The plumage is predominantly black-brown, but the males in particular have a characteristic coloration. This goes from the chin to the middle of the throat and the ear covers from gray-brown to reddish. From the middle of the throat to the chest, the plumage is colored orange-red and this color continues to the neck and forms the eponymous collar. This can be seen quite clearly in the field, especially in sunlight. The orange-red collar shows varying degrees of brown spotting in adult birds. Below the nape of the neck, the top is quite uniformly black-brown, only the rump and the upper tail-coverts are a bit lighter. The coloring of the underside is also quite uniform from the neck to the under tail-coverts, it is somewhat lighter compared to the upper side. The tail has a slight bifurcation, but it often appears cut straight. When the tail is spread, the tail feathers appear translucent. Compared to the other sympatric species of the subfamily Cypseloidinae, the tail of the red-necked swift is proportionally longer.
In females, it takes longer for the red collar to develop. In some adult females, the collar can be completely absent, females with incomplete colouration of the collar are common. The tail fork of the females is usually less pronounced than that of the males. Young birds show no or only partially reddish plumage, they are generally paler than adults. In addition, the wing feathers and smaller wing covers have a narrow white border.
The agile flight is typical for the genus, the wings are often pointed stiffly downwards. The most difficult thing to distinguish from the Red-necked Swift is the Phelpssegler , which so far has only been sighted once within the Red-necked Swift's range. The Phelpssegler also has a red collar, but its color is more intense. In addition, the Phelpssegler is larger, its tail fork is clearer.
Vocalizations
Red-necked swifts are very happy to shout, a few different calls can be heard, most of which sound insect-like. For example, there is a chattering "kri-kik-kik-kik", which is reminiscent of parrots but is higher, as well as a gasping "tt-tiii-i" or "ttt-tsss" or a very insect-like sounding, accelerating " Tschi Tschi Tschue-hu ".
Spreading and migrations
The distribution area extends over Central and South America , especially the South American part is very fragmented. The Red-necked Swift occurs in Central America mainly on the Pacific side of the Cordilleras. The northernmost occurrences are found in the Mexican states of Sinaloa , Durango , Zacatecas , Hidalgo and Veracruz . From there the distribution area extends south to Guatemala in three different mountain regions. The species also occurs in the high altitudes of El Salvador , Honduras and Costa Rica to the west of Panama . The red-necked swift is apparently missing in Nicaragua , in Belize the status of the species is unclear.
The South American distribution area is almost exclusively limited to the Andes and the adjacent Cordillera mountains. The easternmost occurrences are in Guyana , Trinidad and the Venezuelan state of Sucre . From there, the area extends westward over Carabobo to the Andes in Táchira . In Colombia , the species occurs in all parts of the Andes and in the Sierra de San Lucas , but is absent in the Sierra Nevada de Santa Marta and the Serranía del Perijá . The red-necked swift is found in Ecuador in both the western and eastern parts of the Andes, south of which the distribution area is very fragmented and limited to the eastern part of the Andes, it extends over Peru to the Yungas near Cochabamba in Bolivia .
The populations of South America are considered to be resident birds . There are migrations in the north of the Central American part of the range. Presumably, the birds from northern Mexico leave the breeding area in winter, this is supported by the observation of evidently migrating flocks from mid-March to May in western Mexico. Most of the observed migratory movements are only likely to be a lapse from the high altitudes to lower areas, which can be observed in Central America from October to February in particular. There is no evidence that the populations of Central America overwinter in South America.
habitat
The red-necked swift occurs mainly in mountain regions. In Central America the species is typically found at altitudes over 1500 meters, the highest Central American occurrences were in Mexico at 3000 meters, in Costa Rica at about 2500 meters. However, the species is occasionally observed in valleys at an altitude between 300 and 400 meters foraging, sometimes even at sea level. The Red-necked Swift can normally be found in the South American Andes at an altitude range between 1000 and 2600 meters, but it has also been spotted there at an altitude of 3400 meters. In Trinidad , the nesting sites are located in lower elevations and also at sea level, but when the weather is good, the sailors only look for food above the higher forests of the island.
The red-necked swift occurs in various mountain landscapes; it searches for food both over wooded areas and over the alpine forest-free zone. Wild gorges seem to correspond more to the preference of the species than gentle high valleys or plateaus. Especially when it rains at higher altitudes, the red-necked swift can also be seen foraging in the lowlands. The species can often be found near waterfalls.
Behavior and food acquisition
Red-necked swifts are sociable and can often be found together with other sympatric species of sailor, especially the collar swift ( Streptoprocne zonaris ), with whom the red-necked swift not only hunts for food, but also spends the night together. The bond with individuals of smaller species, especially of the genus Chaetura , is more spontaneous and less permanent.
In the Andes, schools with more than 100 individuals are not uncommon. Compared to most other sailors, red-necked swifts search for food at higher altitudes above the ground, and in mixed flocks it has been observed that the red-necked swift tends to hunt above the other species. Like all sailors, the species mainly feeds on insects , including swarming ants . In Ecuador, between September and October, red-necked swifts were seen hunting together with other sailors among huge swarms of various small beetles.
Reproduction
In Central America, the breeding season is in summer and often begins during the rainy season. In Trinidad it lasts mainly from May to August, but can drag on over the entire summer half-year to October. An apparently breeding bird was detected in Colombia in July.
Nesting near the water, usually between half a meter and three meters from the water surface, is typical for the genus. Typical nest locations are under overhanging rocks or at small waterfalls in damp, narrow brook gorges, the humidity is never below 95 percent. But there are also other nest locations, in Trinidad one nest was found in a surf cave and another under a bridge. There was also a strong loyalty to the nesting site.
The shape of the nests depends on the available nesting material. The nest is attached to a vertical structure, the shape usually corresponds to a half-shell or half a cone with the point downwards, with a not too large depression in the middle. As Nest component almost exclusively Moose used only small amounts of clay are installed, usually at the base or for wall mounting. During the breeding and rearing of the young, the nest construction is optimized by the adult birds in order to better secure the eggs and young birds from falling out. The mean nest width was determined to be 104 millimeters, the central cavity was on average around 66 millimeters deep.
The clutch basically consists of two eggs. The mean measured egg size was 23.62 × 15.49 millimeters. The eggs are incubated for around 24 to 26 days and the young take 40 to 42 days to fledge. Presumably as a result of the damp and cool nest location, the young develop a fur-like, thick downy plumage. In a study in Trinidad, young birds hatched from 55 percent of the eggs laid, 68 percent of which flew out, resulting in a breeding success of around 36 percent.
Existence and endangerment
The species occurs in large parts of the range only spatially limited, but it seems to be rarer in Central America than in South America, where it is common in certain parts of the Andes and can be found regularly. BirdLife International estimates the size of the range to be approximately 1.39 million square kilometers. The species is classified as not endangered.
Systematics
The red-necked swift used to belong to the genus Cypseloides . The preferred nest location and the nature of the nest speak in favor of this assignment. This was mainly controversial because the Red-necked Swift, in contrast to all other Cypseloides species, lays two eggs instead of just one - with the exception of the similar Phelpssegler, which also lays two eggs . In 1992, Marín and Stiles also pointed out that plumage characteristics, breeding biology and other characteristics speak for an assignment of the species to the genus Streptoprocne . This view is now widely recognized. The Phelpssegler, the sister species of the Red-necked Swift, is now included in the genus Streptoprocne .
There are three subspecies of the red-necked swift:
- S. r. rutila ( Vieillot , 1817 ): The nominate form occurs in the northeastern part of the South American distribution area, from Venezuela to Guyana and on Trinidad .
- S. r. griseifrons ( Nelson, 1900 ): The representatives in western Mexico are assigned to this subspecies, namely in Nayarit , in the west of Jalisco , in the west of Zacatecas and in the south of Durango . They are paler in color than the other members of the species, the underside is sooty gray-brown, and the feathers on the forehead, the reins and above the eyes have a pale gray border.
- S. r. brunnitorques ( Lafresnaye , 1844 ): The birds from southeast Mexico to Peru belong to this subspecies. But there are hardly any differences to the nominate form and the status of this subspecies is controversial.
literature
- Phil Chantler, Gerald Driessens: A Guide to the Swifts and Tree Swifts of the World. Pica Press, Mountfield 2000, ISBN 1-873403-83-6 .
- Joseph del Hoyo, Andrew Elliot, Jordi Sargatal (Eds.): Handbook of the Birds of the World. Volume 5: Barn-owls to Hummingbirds. Lynx Edicions, 1999, ISBN 84-87334-25-3 .
Individual evidence
- ↑ CT Collins: A new species of swift of the genus Cypseloides from northeastern South America. Natural History Museum, Los Angeles 1992.
- ↑ a b c M. A. Marín, FG Stiles: On the biology of five species of swifts (Apodidae, Cypseloidinae) in Costa Rica. In: Proceedings of the Western Foundation of Vertebrate Zoology. 5, 1992, pp. 286-351.
- ↑ a b c d e f g h i j k l m n o p P. Chantler, G. Driessens: A Guide to the Swifts and Tree Swifts of the World. P. 101ff.
- ^ Steve NG Howell, Sophie Webb, A Guide to the Birds of Mexico and Northern Central America. Oxford University Press, New York 1995, ISBN 0-19-854012-4 , p. 386.
- ↑ CT Collins: The comparative biology of two species of swifts in Trinidad. In: Bulletin of the Florida State Museum. Vol. 11, 1968, p. 299.
- ^ A b c D. W. Snow: Notes on the biology of some Trinidad swifts. In: Zoologica. 47, 1962, pp. 129-139.
- ↑ CT Collins: The comparative biology of two species of swifts in Trinidad. In: Bulletin of the Florida State Museum. Vol. 11, 1968, p. 282.
- ↑ BirdLife International: Species Factsheet - Chestnut-collared Swift ( Streptoprocne rutila ) . Retrieved November 15, 2010.
Web links
- Streptoprocne rutila in the endangered Red List species the IUCN 2010. Posted by: BirdLife International, 2009. Accessed November 13 of 2010.
