The swallow violet-green ( Tachycineta thalassina ) is a small North American passerine in the swallow family. These airborne insectivores are distributed along the west coast from Alaska to Mexico, extending as far east as Montana and Texas. With a very similar appearance to the swallow tree, these individuals can be identified by the sides of white clumps that appear to separate their green backs and purple tails. Violet-green swallow is a secondary hole cavity, found in a number of habitats including deciduous forests and needle tree species. In addition to nesting in tree holes in this habitat, they are also widely observed lodged in large cliff crevices.
Video Violet-green swallow
Description
Different body shapes of swallows differentiate them from other passerine birds. Long and sleek wings, slim body evolved to catch insects while in flight. The body of the purple-green swallow bird is no exception. With an average body length of 5Ã,¼ inch (13 cm), the purple-green swallow is slightly shorter and looks more compact in flight compared to other Hirundinidae family members. The violet green violet is very similar to the North American swallow, but can be distinguished by its shorter wings and color.
Colouration
The violet-green swallow gets its name from staining on his back and butt. This species is best identified by the shiny green on the top of the head and back as well as the purple hoods on the back of the neck, buttocks and tail. Under the green back, the remaining wings are bronze gray. Similar to other swallows, T. thalassina is white below, but it is different that white continues to the side-rump-patch that almost meets at the base of the tail. These white side ribs sometimes look like a continuous line while in flight. White also extends to the cheeks, partially circling the eyes. The incision in the purple-green swallow tail is slightly shallower than the swallow, but deeper than the relatively flat tail of the swallowed cliff.
Violet-green swallow shows very little sexual dimorphism, with adult males showing only a brighter color than adult women. In addition, the white cheeks are not protruding and their heads are more than green in women. Adolescents are not easily identifiable compared to adults because of their boring color. Similar to other swallows, especially the swallow, which is green-lilac is white at the bottom and grayish brown on top. However, gradual changes in color and visible (but slightly reduced) white cheeks may help identify the individual teenagers of the species.
Standard measurements
Maps Violet-green swallow
Taxonomy
This kite has been well studied ecologically, but only recently has their phylogeny been thoroughly researched. The Swallow is a passerine bird grouped in the Hirundinidae family. The Hirundinidae family is divided into two subfamilies: Pseudochelidoninae , containing two species of river martin, and Hirundininae , composed of all martin and other swallows. The 82 species in the subfamili Hirundininae are further grouped into three groups: mud nesters, basal racial and martins nuclei, with purple green swallowing falling to the last. Violet-green swallows are one of 9 New World tree species that ingest in the genus Tachycineta . This genus is a monophyletic group and is considered a sister taxa of all the other New World swallows.
Violet-green swallow is an important member of Tachycineta clade due to their large geographical range and because they are one of 2 species that breed in North America. It is agreed that Tachycineta is divided into North American and South clusters, but the phylogenetic placement in the genus depends on the type of analysis used. The violet green Eagle is a member of the North American group, along with T. bicolor (swallowing North American trees), T. euchrysea (swallowing Hispaniola and Jamaican gold) and > T. cyaneoviridis (Bahamas swallow). Analysis of the mitochondrial genome has placed T. thalassina as a bronchial taxon of the swallowing Caribbean, T. euchrysea and T. cyaneoviridis , with all 3 species forming brothers women clade for T. bicolor . The analysis of the nuclear genome and the consensus of the two methods has reorganized this North American clade, alternately with the closest sister taxon of T. thalassina between T. cyaneoviridis and T. euchrysea . Nevertheless, the taxonomy of purple green swallowing is well understood to the level of the genus, after which some uncertainty surrounds the placement of T. thalassina in the North American clade of the genus Tachycineta >.
Subspecies
Violet-green swallow is divided into three subspecies, T. t. thalassina , T. t. brachyptera and T. t. lepida differ in breeding range and wing length. T. t. thalassina has slightly longer wings and has been known to proliferate as far as Alaska, while the short wing T. t. brachyptera breed further south in California and Mexico. Not all literatures agree on T. t. lepida as the 3rd subspecies, and little information is available to help distinguish it from other subspecies.
Hybridization
Hybridization has been known to occur among swallows, with some cases involving reported violet greens. Breeding between green-swallow violets and both tree swallows and barns have been noted on separate occasions, but producing offspring is not observed. In 2000, the strange feather from a swallow seen in British Columbia, Canada showed the possibility of successful hybridization of the violet-green swallow and cliff. Nevertheless, these observations are rare then why minimal research has seen hybridization of swallowing.
Habitat
The habitat types occupied by violet-green swallows vary depending on the geographical location and altitude. Beyond their reach, these birds can be found in deciduous forests, conifers and mixtures, as well as in canyons and near great cliffs. Breeding and non-breeding habitats do not differ greatly except breeding habitats are usually at lower elevations. Violet-green swallows have also been observed lodged around buildings in more sedentary areas.
Distribution
Violet-green swallow is a predominantly western species, with rare individual appearances in eastern North America. Distribution of species can be divided according to a recognized subspecies, but the entire range ranges from central Alaska to Mexico. Longitudinally, the range is bordered by the western coast of Alaska, British Columbia and the United States, and extends eastwards to southwestern Alberta, Montana, Dakotas and Texas. The breeding range covers almost all distribution, while the winter range is limited to Mexico.
Behavior
Vocalizations
There are many knowledge gaps around the vocalization behavior of purple green swallowing. These gaps include vocalizations made during initial development, alarm calls and daily dialing patterns. Little information is available showing two main classes of vocalizations, calling chee-chee and twitter .
Chee-chee call
This call is most commonly heard when a violet green bird interacts with another swallow, either while foraging, chasing on a plane or approaching a nesting place. Swallowing swarms have been recorded making calls to chee-chee , suggesting their use in social cohesion. Adolescents have also been observed making this vocalization while waiting to be fed by adults, implying that it plays a role in the recognition of parent-teenagers.
Twitter call
The observation of purple green swallowing makes twitter a call usually associates vocalizations by showing courtship and formation of new territory. Twitter calls are only heard in flight, either by men escorting women or during intraspecific short territorial disputes. Mixing of two calls occurs occasionally, but little ecological research can explain its use.
Diet
Similar to other swallows, swallow green violet is a special air-insect eater, capturing and eating its prey while flying. However, they have been known to feed higher in the sky than most other swallows. An abdominal examination of several individuals has presented a variety of diet items, including insects such as ants, beetles and flies and other arthropods such as spiders. On rare occasions these birds have been observed foraging on the ground, but such events are an exception to their typical eating habits.
Reproduction
Violet-green swallow usually will arrive at their breeding area for weeks before the start of reproduction. The location depends, intercourse takes place mid-May with eggs laid in early June, followed by several weeks of incubation before hatching. The average clutch size is 5 eggs, with the female lying about 1 per day. During the weeks after hatching, their parents feed the young when they slowly start growing their feathers. After about 3 weeks the young is ready to leave the nest. It is more common for couples to reproduce once per breeding season, but the second brood has been observed on certain occasions.
Nested sites
Violet-green swallow is a secondary cavity cavity, which means they usually nest in natural holes or previously occupied nests. Some breeding pairs will even go as far as snatching nests from other species. The majority of the purple-green swallow nest is in tree holes dug by other animals or in large cliff crevices. Because of their dependence on large trees, swallowing violet green is strongly influenced by forest management practices. In addition to nesting in natural cavities, violet green birds are also observed to occupy an artificial nest box. Couples usually breed in independent nests, except on cliffs where large colonies can be found nesting together.
Specific egg removal
Violet-green swallows have been observed to work together and compete with various avian species, including western bluebirds. The same field observations recorded a purple green bird laying in an active bluebird nest box. Originally, male bluebirds tried to push swiftlet from the nest, while the female bluebird did not seem to care about the intruder. Apparently the blue birds tolerate the egg breeding action by purple green birds, but the observer returns the next day to find the newly destroyed egg under the nest. This behavior indicates that when it can not access its original nest after physiologically committed to laying its eggs, a purple-green female bird can participate in the pouring of eggs between species.
Specific intensive defense paternity
Violet-green swallow is a secondary hole cavity and an insect-eating air, making men vulnerable to nest rivalry and mate. To avoid being cuckolded, men spend more time keeping their spouses than their nests, in opposition to swallowing a tree. This paternal-style behavior emphasizes that non-territorial green-green swalows exhibit a greater spousal competition than the egg-laying competition.
Cooperation between species
Some accounts swallow green violets establishing cooperative relationships with other species have been noted. From 1981 to 1982, three independent swallow pairs were observed together to occupy the western bluebirds nest box. This green-violet swallow protects the nesting place, removed the fecal sac from the box and fed the bluebird fledglings without resistance from the mature Western bluebirds birds. Although the sample size is too small to hold statistical significance, new survival grows larger when green-violet fish provides active treatment. It is believed that the Swallow takes advantage of the cooperative relationship by inheriting the nest box after the parents and flebiru birds go.
Interspesifik Competition
Similar to occasional observations of purple green swallowing establishing intercultural cooperation relationships, they have also engaged in intercountry competition for spawning sites. One example from 1974, noting the competitive behavior between mountain grips and swallowing purple green. A physical quarrel begins when a pair of swallows tries to take over the nesting place occupied by a pair of girls and fledglenya birds. After a few air combat, the girls returned to their nest and managed to survive the purple green swallowing attack in the future. The same field observer noted a similar quarrel between violet green birds and hairy woodpeckers, which produced similar results. This species is a permanent resident, allowing them to choose a nesting place first, while the purple green bird is a summer resident with a late breeding habit. Thus, the scarcity of proper nesting sites can lead to competitive behavior among these species in swallowing green violets. Similar observations of competitive behavior for potential spotting sites have been observed between acorn woodpeckers and purple green fish overpasses.
Torpor
It has been speculated that certain birds, including swallows, enter a dreary state during the harsh winters. Some observations about the decline in body temperature and metabolic rate have been recorded in the green-violet swallow, the first case occurred in 1965 near the Death Valley National Monument in Saratoga Springs, California. Field observers noted the 3 "dead" individuals on the eastern slopes of the dunes early in the morning after a cold and windy night. Upon closer inspection, violet green birds do small movements, such as opening their eyes, but not wrestling while being handled. The physical appearance of swallowing, including the position of their head in relation to the slope and the feathers of their feathers are similar to other birds that are dormant. Despite the lack of a thermometer, obviously these three men were in a hypothermic state for about 45 minutes after the sun began to rise. Finally 3 swallows awkwardly to fly, marking the end of their suspended animation.
Ectoparasit control
Sunbathing
In addition to reaching the hypotermic temperature of the limit during a suspended animation, swallowing violet green has been observed to behave similarly to the hypertermic individuals while basking. Indications of this activity include the orientation of their wings and tails, circumstances such as trance and occasional balance of balance. Studies have shown that the increase in the temperature of the feathers during sunbathing can control ectoparasites. The basking period in short-green swallow violets and depends on ambient temperature and wind speed, but usually occurs after an increase in parasitic charge near the nest end.
References
External links
- Violet-green swallow videos in Internet Bird Collection
- Account of purple-green bird species - Cornell Lab of Ornithology
- Violet-green swallow - Tachycineta thalassina - USGS Patuxent Bird Identification Information Center
- Photo gallery violet-green swallow VIREO
Source of the article : Wikipedia
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