Chestnut-collared Swift

Male Rothalssegler in the Asa Wright Nature Centre, Trinidad

The Rothalssegler ( Streptoprocne rutila, Syn: Cypseloides rutilus ) is a species of bird in the family of sailors ( Apodidae ). The plumage is predominantly black brown. However, it has a strongly contrasting red collar, making it the Rothalssegler next to its sister, the Phelpssegler, the only sailor with somewhat more prominent notice staining. With 13 centimeters body length of Rothalssegler is quite small, it is the smallest member of the genus Streptoprocne.

The distribution area is very fragmented and restricted to Central and South America. There the Rothalssegler is found mainly in the Cordillera and adjacent mountain ranges. The nests are built on vertical structures. The nesting sites are typically near water, for example in narrow moist ravines or near waterfalls.

Features

Appearance

The body length is about 13 centimeters. For the wing length millimeters were determined in males values ​​from 116.0 to 130.5, while females it was 112.0 to 124.5 millimeters. The weight is approximately 21 grams.

The plumage is mainly dark brown, but especially the males have a characteristic coloration. This is it from the chin over to the middle of the throat and the ear-coverts gray brown reddish. From the middle of the throat to the chest plumage is colored orange and this color continues to the neck and forms the eponymous collar. This can be quite clearly seen in the field, especially in the sunlight. The orange-red collar shows in adult birds varying degrees of brown mottling. Below the neck, the top is quite uniform black-brown, only the rump and upper tail-coverts are somewhat brighter. Also the color of the underside is quite uniform from the neck to the under tail-coverts, it is compared to the top a little brighter. The tail has a slight bifurcation, but he often seems just cut off. In spread- tail, the tail feathers appear translucent. Compared to the other sympatric species of the subfamily Cypseloidinae the tail of the Rothalsseglers is longer in proportion.

In females, it takes longer for the red neck band developed. Some adult females the collar can also be entirely absent, females with incompletely formed coloring of the collar are common. The tail fork in the female is usually less pronounced than that of males. Young birds show no or only partly reddish plumage shares, they are also usually total paler than adult animals. In addition, the flight feathers and smaller wing-coverts have a narrow white collar.

The application rich air is typical of the genus, while the wings are directed often stiff acting downwards. The most difficult to distinguish from Rothalssegler is the Phelpssegler, but was so far only been seen once inside the distribution area of the Rothalsseglers. The Phelpssegler also has a red collar, but its color is more intense. In addition, the Phelpssegler is bigger, his tail fork is clearer.

Vocalizations

Rothalssegler are very ruffreudig, some different types of calls can be heard, of which sound the most insect -like. For example, there is a schwätzendes " kri - kik - kik - kik ", but which recalls is higher at parrots, also a wheezy "tt - TIII -i " or " ttt - tsss " or even a very insect -like sounding, faster nascent " chi chi chu -hu ".

Dissemination and hikes

The distribution area extends across Central and South America, especially the South American part is very fragmented. The Rothalssegler comes mainly found in Central America on the Pacific side of the Cordillera. The northernmost occurrence can be found in the Mexican states of Sinaloa, Durango, Zacatecas, Hidalgo and Veracruz. From there, the range extends south to Guatemala in three different mountain regions. Furthermore, the species occurs in the highlands of El Salvador, Honduras and Costa Rica before into the western Panama. The Rothalssegler apparently missing in Nicaragua, Belize in the status of the species is unclear.

The South American area of ​​distribution is limited almost exclusively to the Andes and the adjacent kordillerischen Mountains. The easternmost deposits are in Guyana, Trinidad and the Venezuelan state of Sucre. From there, the area extends westward across Carabobo up in the Andes Táchira. In Colombia, the species occurs in all parts of the Andes and in the Sierra de San Lucas, but it is missing in the Sierra Nevada de Santa Marta and the Serrania del Perijá. The Rothalssegler found in Ecuador, both in the western and the eastern part of the Andes, south of the area of ​​distribution is very fragmented and limited to the eastern part of the Andes, it extends beyond Peru to the Yungas in Cochabamba in Bolivia.

The populations of South America are considered to be resident birds. In the north of the Central American part of the range, there are hikes. Probably leave the birds from the north of Mexico in winter breeding area, but the observation obviously speaks migratory flocks from mid- March to May in western Mexico. In most observed pulling movements but it might be just a lapse from the high altitudes in low -lying areas, which is mainly observed in Central America from October to February. There is no evidence that the populations of Central America, wintering in South America.

Habitat

The Rothalssegler occurs mainly in mountainous regions. In Central America the species is typically found in a height range over 1500 meters, the highest Central American presence in Mexico were at 3000 meters, in Costa Rica at about 2500 meters. The species is also occasionally observed in valleys at an altitude between 300 and 400 meters in search of food, sometimes even at sea level. Normally the Rothalssegler in the South American Andes is found in a height range between 1000 and 2600 meters, but he was spotted there too at an altitude of 3400 meters. In Trinidad, the nesting sites are at lower altitudes and at sea level, the sailors go but in good weather only through the higher forests of the island in search of food.

The Rothalssegler occurs in diverse mountain landscapes, it goes both wooded areas, as well as through the alpine forest-free zone in search of food. Wild gorges seem thereby more likely to correspond to the preference of the species as gentle valleys or plateaus. Especially when it rains at higher altitudes, the Rothalssegler is however also be seen in search of food in the lowlands. Frequently, the species is found near waterfalls.

Behavior and food acquisition

Rothalssegler are gregarious and often together to meet other sailors sympatric species, especially with the collar sailors ( Streptoprocne zonaris ), with which the Rothalssegler is not just together in search of food, but also jointly bleary-eyed. Binding to individuals of smaller species, particularly the genus Chaetura is spontaneous and not so permanent.

In the Andes, swarms are not uncommon with more than 100 individuals. Rothalssegler go there compared to most other sailors at greater heights above the ground in search of food, in mixed shoals has been observed that the Rothalssegler tend chases above the other species. Like all sailors, the species feeds mainly on insects, including ants are swarming. In Ecuador Rothalssegler September-October were observed jointly with other sailors in the hunt in huge swarms of various small beetles.

Reproduction

In Central America, the breeding season is in the summer and often begins during the rainy season. In Trinidad it takes mainly May to August but may extend over the entire summer half year to October. In Colombia, an obviously brooding bird was detected in July.

Typical of the species is nesting near water, usually located between a half and three meters from the water surface. Typical nesting sites can be found under overhanging rocks or small waterfalls in damp, narrow ravines, the humidity never drops below 95 percent. But other nesting sites are there in Trinidad was found a nest in a sea cave and another under a bridge. There is also a strong Nistplatztreue was found.

The shape of the nests is limited by available nesting material. The nest is attached to a vertical structure, the form usually corresponds to a half- cup or half a cone with the top down, with a not too large depression in the center. As nest component almost exclusively mosses are used, only small amounts of clay to be installed, usually at the base or wall mounting. During incubation and during the breeding nest construction is further optimized by the adult birds to better secure the eggs and young birds from falling out. The mean nest width 104 millimeters were determined, the central nest hollow was on average about 66 millimeters deep.

The nest consists basically of two eggs. The average measured egg size was 23.62 × 15.49 mm. The eggs are incubated for about 24 to 26 days and the boys need 40 to 42 days until they fledge. Probably as a result of damp cool nest site to develop the boys a furry - thick Dunengefieder. In a study in Trinidad slipped from 55 percent of eggs laid young birds, 68 percent of them flew out, it resulted in a breeding success of about 36 percent.

Inventory and risk

The species occurs in many parts of the range before only a restricted area, while it appears to be less common than in South America where it is common in certain parts of the Andes and can be found regularly in Central America. BirdLife International estimates the size of the range to about 1.39 million square kilometers. The species is classified as unthreatened.

System

Previously, the Rothalssegler the genus Cypseloides was attributed. For this assignment saith the preferred nest site and the nature of the nest. But this was the main reason controversial since the Rothalssegler in contrast to all other types of Cypseloides two instead of just laying an egg - with the exception of two egg-laying also similar Phelpsseglers. Marín and Stiles presented in 1992 out also that plumage characters, breeding biology and other features for classification of the type of the genus speak Streptoprocne. This view is now widely recognized. Also the Phelpssegler, the sister species of Rothalsseglers is now to the genus Streptoprocne.

When Rothalssegler three subspecies are distinguished:

• S. r. rutila ( Vieillot, 1817): The nominate form is found in the north-eastern part of the South American distribution area, from Venezuela to Guyana and Trinidad.
• S. r. griseifrons ( Nelson, 1900): This subspecies are the representatives in western Mexico attributed, in Nayarit, Jalisco to the west, Zacatecas to the west and south of Durango. They are paler in color than the other representatives of the species, the underside is sooty gray-brown, and the feathers of the forehead, the reins and above the eyes have a pale gray hem on.
• S. r. brunnitorques ( Lafresnaye, 1844): The birds of southeastern Mexico to Peru belong to this subspecies. However, there are few differences to nominate and the status of this subspecies is controversial.