Rief-beaked ani
| Rief-beaked ani | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Riefenschabelani ( Crotophaga sulcirostris ) |
||||||||||||
| Systematics | ||||||||||||
|
||||||||||||
| Scientific name | ||||||||||||
| Crotophaga sulcirostris | ||||||||||||
| Swainson , 1827 |
The Riefenschnabelani ( Crotophaga sulcirostris ) is a member of the genus Crotophaga within the family of the cuckoos (Cuculidae). The black, strikingly long-tailed bird is found in an extensive area from the southern Texas Gulf coast south to northwest Argentina. He looks for his insect prey in family groups that can contain more than 20 individuals, especially on the ground. Grooved bill anise are not brood parasites , but primarily community breeders . Usually several females lay their eggs in a jointly built nest and raise the young together with the other group members. The monotypic species is common in places and its population is not endangered, but is increasingly being displaced by the closely related smooth-billed ani in some coastal areas along the Central American and South American Pacific coast .
Appearance
The Riefenschnabelani is the smallest of the three species in the genus Crotophaga . The difference in size to the smooth-beaked ani, with which it occurs sympatricly in some regions of its distribution area, cannot, however, be ascertained by field ornithology. With a total length of around 32 centimeters, of which a good half is the tail, Rief-bill anise is about the size of Turkish pigeons , but significantly lighter than them. Males of this species weigh on average around 80 grams, the slightly lighter females 67 grams. Differences in size between the sexes are insignificant, there is no color dimorphism . The best distinguishing feature, which can only be used up close, is the slightly larger beak height of the male.
Whistled-billed anise are generally long-tailed, uniformly black birds with a very long tail, which is often pointed upwards, especially on the ground. Up close, various bluish, bronze-green or purple shimmers depending on the incidence of light can be seen. The plumage of the neck and the upper part of the head can protrude radiantly, especially when it is very hot or when birds are sunbathing, so that the black skin is visible underneath. The mighty beak is black, the upper beak, raised evenly arched from the beak tip, but does not reach the height of the head vertex at its ridge. It is named after the multiple, almost parallel, arched and furrowed upper beak; the lower mandible is almost straight and smooth, and also slightly furrowed in older individuals. As with all aniseed, the beak looks compressed to the side. The iris is dark brown or black. The strong feet, toes and claws are also black.
Immature birds are very similar to adult birds, but the plumage is missing, the arched elevation of the upper bill is only partially recognizable and the beak notches are only hinted at.
Grooved-billed anise is difficult to distinguish in field ornithological terms from smooth-billed anise, with which it occurs in some areas. The best distinguishing features, and also useful at a certain distance, are the different vocalizations of the two types. Up close, adult long-billed anise can be identified based on the shape of the beak and the furrows in the beak. The neck plumage shimmers greenish in the crested anise, bronze-brownish in the smooth-billed anise. In immature individuals, in which both the plumage and the beak notches are missing, a reliable field ornithological identification is very difficult and often hardly possible.
Like all aniseed, deep-billed anise gives off an unpleasant, pungent-pungent odor in stressful situations and during the night's rest, the biological meaning of which has not been adequately researched.
voice
Like all aniseed anise, Riefenschnabel anise are very happy to call and have an extensive repertoire of calls. Their surprisingly high calls are not very loud, however. A characteristic call that is constantly heard in the communication of the group members is a two-syllable, stringed Ti-ju (u) , whereby the second syllable is somewhat stretched and can also be modulated. Very high-pitched, drawn-out iiiiiije sequences that begin with a plosive sound are also often heard .
distribution and habitat
The range of the species extends from the Gulf coast of southern Texas and the Gulf regions of Mexico over the whole of Central America and eastwards along the South American Gulf coast to Guyana . The coastal Gulf Islands of Mexico and Central America such as Cozumel and the islands off the South American Gulf coast, such as Trinidad, are also populated . Some of these islands, such as Bonaire , Curacao or Aruba , the species only reached in the course of the past century. On the Pacific side, Rye-billed anise breed from the Mexican province of Sonora southwards across Central America and the South American Pacific-near areas of Colombia , Ecuador and Peru to northern Chile and the extreme northwest of Argentina .
Brood occurrences are extinct in Louisiana and in the southernmost areas of Lower California and some offshore islands.
In contrast to the other two species of the genus, black-bellied anise can usually be found in only moderately humid areas. Shrubbery strips and islands of trees on the edges of pastureland, meadows, orchards or plantations, cleared areas with isolated trees and bushes, but also open, only loosely tree-lined or bush-strewn grasslands form preferred breeding habitats. Rief-beak anise is particularly common in the lowlands and at altitudes of up to 500 meters. However, irregular breeding occurrences are known from significantly higher altitudes of up to 2700 meters in Ecuador and Peru.
Space requirements
Crab anise occupy and defend a breeding territory. The territory sizes vary between 3 and 11 hectares. Territories in wetlands are usually smaller than those in pastureland. Agonistic behaviors mainly trigger groups of conspecifics, other aniseed and potential enemies, especially nest predators such as snakes, monkeys, birds of prey, raccoons and possums .
hikes
Rief-beak anise are mainly standing or line birds. Most of the breeding territories are abandoned after the breeding season and the birds move to more humid areas, often in marshland, where some family groups can unite and sometimes form societies of 30 to 40 birds. Breeding birds also migrate from higher regions to lower ones. These movements are generally small-scale and irregular. As far as is known, only the breeding birds of northern Sonora completely leave their breeding areas. Hiking routes, distances and destinations are not yet known.
Although crested anise are not powerful and persistent fliers, solitary birds or small groups roaming around outside of the breeding season have been observed in almost every state in the United States and southern Canada. One observation of a drifting bird comes from Socorro , an island in the Mexican Revillagigedo Archipelago .
Food and subsistence
Like the other two species of this genus, Rief-beaked anise feed itself and its young mainly on insects. Other invertebrates such as spiders and ticks, as well as small mammals, birds and lizards also play a certain role. Occasionally, bird eggs also appear to be part of the diet of the species. Fruits, berries and seeds make up a seasonal supplement. Grasshoppers , beetles , cockroaches , cicadas , ants and termites predominate among the insects .
Shoveled anise almost always look for and capture their food in groups, especially on the ground. They are seldom in search of food in bushes or trees. Hopping or striding, they read insects from the ground or vegetation. They often follow herd animals, from which they pick ticks and blood-sucking insects, pick up the frightened insects, or in whose dung they look for beetles and other invertebrates.
behavior
Like all cuckoos, scarlet anise are diurnal. Your activity time roughly corresponds to the length of the day. They spend the nights in groups, preferably in higher thorn-reinforced bushes. The species can often be seen sunbathing and water bathing. During the morning sun spread them in the way some New World vultures wings accordingly they are in some Central American regions Zopilotillo - Geierchen called.
Like all aniseed, deep-beaked anises live primarily in family groups. Single breeding pairs are rare and have a tendency to join groups. These consist of several monogamous pairs and sometimes a few unmated adult individuals as well as the offspring of a breeding season, at the end of which such a group can have 20 members or more. The couple partners remain largely monogamous, at least seasonally, but couples usually last longer, often lifelong. Pairs also form units within the group. Extra pair copulations do occur but are rare. All activities such as foraging, nest building, brood care and defense against potential enemies take place in the social association. All group members, but especially the mated, keep close physical contact, rest next to each other, look after each other's plumage and communicate with each other constantly. Outside the breeding season, several family groups often come together and form loose associations. During this time, the exchange of group members and the reorganization of family groups also take place.
Breeding biology
Deep-billed anise become sexually mature as yearlings. The breeding seasons spread very strongly according to the very large width of the distribution area. In the Central American main distribution area, the main breeding season is in the rainy season between June and November. Usually there are two annual broods, occasionally three.
The community nest is set up by all family members in a few days. Occasionally, the nests of other birds, especially those of the Jackdawgrackel, are used or adapted. Newly built nests are quite extensive structures made of twigs, tendrils and thorns, lined with soft materials on the inside and camouflaged with leaves and fresh green branches on the outside. The nests are 3–5 meters high, well hidden in bushes or trees.
Eggs are apparently laid according to the hierarchy of the respective female, with the lowest ranking beginning. The following laying females remove some eggs from the already existing clutch. The clutch size depends primarily on the number of laying females. One female has about 4 eggs, two females up to 9, and three females about 12. Clutches with over 20 eggs were found, the largest actually incubated clutch comprised 13 eggs. The greenish bluish eggs with a whitish layer of lime are very large and heavy with a size of 32 × 24 millimeters and a mass of 11 grams in relation to the body size and body mass of the females. All adult family members incubate alternately during the day, but only one male, usually the partner of the last layer, during the night. As with all aniseed, the incubation period is very short at 12-14 days. The chicks are fed, hoed or shaded by all group members; they develop very quickly. They leave the nest at about 10 days. At this age they are capable of short, fluttering flights, they become fully airworthy at three weeks. Although they are already looking for food independently at this age, they will be looked after by the group members for another three weeks. Two month old young birds help with subsequent broods. Young birds remain at least until the beginning of the next breeding season in group association before they usually solitary, dismigrieren . A not inconsiderable number of young birds also remain in the birth group and breed there for the first time.
Breeding success and life expectancy
The breeding success, the escape rate and the achievement of independence at around six weeks are low.
Many clutches are lost through predation. The most important nest predators are various species of tree-climbing snakes and possums. At least 50% of all clutches are destroyed. Often the brooding male is also eaten during nocturnal attacks. Nestling mortality and losses in the first few weeks of being self-employed are also very high at over 50%. Overall, only just under one young bird per female experiences the end of a breeding season, with the best values being found in two-pair group associations.
Scalloped anise are preyed on by many predators. They include some birds of prey, owls, snakes, raccoons, opossums and carnivorous bats, especially the great spit-leaf nose . No data are available on the maximum age of ringed anise.
Systematics
The species belongs to the small genus Crotophaga , to which the giant ani and the sister species smooth-beaked ani also belong. Sister genus is the monotypical genus Guira , which is also restricted to South America . The species is monotypical. The two described subspecies from the extinct populations of southern Baja California and western Mexico have not been widely recognized.
Existence and endangerment
Rief-beaked anise populate a very large area in North, Central and South America from the tropic to the tropics, with an area of around 2.7 million square kilometers. The total population is estimated at 2 million adult birds. There are no known significant decreases in the population or substantial sources of danger. The species even seems to benefit from the conversion of forest areas into extensively used pastureland. Therefore it is currently considered safe. The population on the Gulf Coast of the USA is decreasing. In some sections of the Pacific coast of South and Central America, the smooth-beaked ani seems to be able to hold their own better than the deep-beaked ani and to displace them regionally.
A subspecies Crotophaga sulcirostris pallidula , which Outram Bangs and Thomas Edward Penard described in 1921, is now considered extinct.
literature
- Bonnie S. Bowen: Groove-billed Ani (Crotophaga sulcirostris). In: The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; 2002 (online)
- Francisco Erize, Jorge R. Rodriguez Mata, and Maurice Rumboll: Birds of South America. Non Passerines: Rheas to Woodpeckers. Princeton Illustrated Checklists. Princeton University Press, Princeton and Oxford 2006. ISBN 0691126887 ; Pp. 240-241.
- Robert B. Payne: The Cuckoos . Oxford University Press 2005. (Bird Families of the World No. 15) ISBN 0198502133 . Panel 1; Pp. 6 and 178-183
- Outram Bangs, Thomas Edward Penard: Notes on some American Birds, Chiefly Neotropical . In: Bulletin of the Museum of Comparative Zoology at Harvard College . tape 64 , no. 4 , 1921, pp. 365-397 ( online [accessed December 1, 2013]).
Web links
- xeno-canto: Sound recordings - Groove-billed Ani ( Crotophaga sulcirostris )
- Crotophaga sulcirostris inthe IUCN 2013 Red List of Threatened Species . Listed by: BirdLife International, 2012. Retrieved February 2, 2014.
Individual evidence
- ↑ a b Robert B. Payne (2005) p. 180
- ^ Bowen (2002) Distinguishing Characteristics
- ↑ Michael D. Sorenson and Robert B. Payne: A molecular genetic analysis of cuckoo phylogeny . In: Robert. B. Payne: The Cuckoos (2005) pp. 6-7
- ↑ Riefenschnabelani audio sample (MP3; 425 kB)
- ↑ a b c d Payne (2005) p. 180
- ^ Payne (2005) p. 179
- ↑ Luis Sandoval, Esteban Biamonte and Alejandro Solano-Ugalde: Previously Unknown Food Items in the Diet of Six Neotropical Bird Species In: The Wilson Journal of Ornithology 120 (1): 214-216. 2008
- ↑ Payne (2005) p. 181
- ^ Bowen (2002) Behavior
- ↑ a b Bowen (2002) Breeding
- ↑ a b Payne (2005) p. 182
- ^ Bowen (2002) Predation
- ^ Bowen (2002) Annual and Lifetime Reproductive Success
- ↑ Michael D. Sorenson and Robert B. Payne: A molecular genetic analysis of cuckoo phylogeny . In: Robert. B. Payne: The Cuckoos (2005)
- ^ Bowen (2002) Systematics
- ↑ data sheet BirdLife international pdf engl.
- ↑ Bangs et al. a. P. 365
- ^ IOC World Bird List Hoatzin, turacos, cuckoos