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Discover the Hidden World of the Black-tailed Trainbearer: A Crown Jewel of the Andes

Black-tailed Trainbearer: The Crown Jewel of the Andes

The Black-tailed Trainbearer (Lesbia victoriae) is a species of hummingbird that can be found in the high-altitude forests of the Andean mountain range. Its scientific name is derived from Queen Victoria, who was the reigning monarch of the United Kingdom during the time when this species was first discovered in the mid-19th century.

Identification

Field Identification

The Black-tailed Trainbearer is a small hummingbird with a distinctive colorful plumage. The adult males have a metallic emerald-green head, back, and wings with a brilliant iridescence.

Its underparts, including the breast and belly, are white, while its tail is black and forked. They also possess a long bill that is slightly curved downwards and black in color.

Female Black-tailed Trainbearers are a bit less flashy, with a duller greenish back and no iridescence. They don’t have the black tail but instead have a rust-colored tail with black subterminal bands.

Their underparts, including their throat, are buff-colored.

Similar Species

The most similar species to the Black-tailed Trainbearer is the Blue-mantled Thornbill, which has a blue-green head and a blue mantle. They have similar forked tails but can be easily distinguished from Trainbearers because Thornbills have a black border on the upper part of their tail while Trainbearers have a subterminal black band.

Plumages

Molts

Black-tailed Trainbearers have two molting cycles per year. They undergo a partial molt after the breeding season, where they replace their body and flight feathers.

They also have a complete molt before breeding, which involves the replacement of all of their feathers. During the breeding season, male Black-tailed Trainbearers develop colorful feathers to attract females, which is called courtship plumage.

After the breeding season, males lose their bright colors, shedding most feathers except for wings and tail feathers. Female Trainbearers maintain the same plumage year-round, but young birds resemble adult females.

Both sexes have brown upperparts and underparts that are dull colors.

In Summary

The Black-tailed Trainbearer is a dazzling bird with a striking plumage that can be found in the Andean Mountain Range. The males have a vibrant emerald-green color, while females have a duller greenish body, and are easily distinguished from similar species like the Blue-mantled Thornbill.

They undergo two molting cycles each year and develop courtship plumage during the breeding season. Whether you are a bird enthusiast or someone who is simply intrigued by the fascinating creatures that inhabit our world, the Black-tailed Trainbearer is a bird that is certainly worth admiring.

The Black-tailed Trainbearer, Lesbia victoriae, has a long and rich history that is intertwined with the Andean Mountain range. In this article, we will explore the systematics of this bird, including its geographic variation, subspecies and related species.

We will also discuss the historical changes to its distribution and how it has been impacted by human activity.

Systematics History

The Black-tailed Trainbearer was first described in 1847 by the German naturalist, Johann Jakob von Tschudi. It was named after Queen Victoria, who was the reigning monarch of the United Kingdom at the time of its discovery.

The scientific name Lesbia victoriae reflects this history.

Geographic Variation

The Black-tailed Trainbearer is found throughout the Andes Mountains in South America, from Colombia to Bolivia. The different populations of this bird that occur along its range exhibit geographic variation in their physical characteristics.

For example, birds in the northern part of its range tend to have a larger size than those in the south.

Subspecies

Currently, there are four recognized subspecies of Black-tailed Trainbearer. Lesbia victoriae victoriae: This subspecies is found in the central and northern Andes range, from Colombia to Ecuador.

The males have a slightly larger size and brighter green color than other subspecies. Lesbia victoriae australis: This subspecies is found in southern Ecuador, Peru, and northwestern Bolivia.

It has smaller body size and a more muted green color than the other subspecies. Lesbia victoriae cyanothorax: This subspecies is found in the mountains of central Peru.

It has a green-blue color on the upperparts and an iridescent violet in its underparts. Lesbia victoriae longicauda: This subspecies is found in the east-central Andes of Peru and has a longer tail than the other subspecies.

The males of this subspecies also have more iridescent violet coloring on their underparts.

Related Species

The Black-tailed Trainbearer is a member of the family Trochilidae, which includes all hummingbirds. There are many species of hummingbirds that can be found in the Andean Mountain range and some of them are closely related to the Black-tailed Trainbearer.

For example, the closely related Blue-mantled Thornbill, Chalcostigma stanleyi, shares a similar black and forked tail but has a blue-green head and mantle.

Historical Changes to Distribution

The Black-tailed Trainbearer has experienced significant changes to its distribution throughout its history. Prior to human influence, it was found throughout its current range in the Andean Mountains.

However, changing landscapes caused by human activity have resulted in changes in its distribution. Deforestation is a significant threat to the Black-tailed Trainbearer, as it relies on cloud forests for its habitat.

The clearing of cloud forests has resulted in a fragmented distribution of the bird throughout its range. This fragmentation has weakened the genetic diversity of the species, which can have long-term negative effects on its survival.

In addition to habitat fragmentation, the Black-tailed Trainbearer has also suffered from the illegal trade of its feathers. The males’ bright green feathers are highly prized, leading to overhunting and reduced population numbers.

In Summary

The Black-tailed Trainbearer is a hummingbird species that is found throughout the Andean mountain range in South America. It has four recognized subspecies that exhibit geographic variation in their physical characteristics.

The bird has been impacted by human activity, with deforestation and illegal trade of feathers being significant threats. The Black-tailed Trainbearer is not alone in these challenges as other species of hummingbirds in the Andean Mountains also face similar threats.

As a result, conservation efforts are underway to protect the bird and its habitat, to ensure that it remains a part of the Andean Mountain ecosystem for generations to come.

Habitat

Black-tailed Trainbearers are primarily found in the high-altitude forests of the Andean Mountains, where they prefer humid environments with plenty of vegetation. They are found in two types of habitat: the evergreen montane forest and the subtropical cloud forest.

The evergreen montane forest is a relatively drier habitat that occurs at elevations between 1,800 and 2,800 meters. The subtropical cloud forest, on the other hand, is a more humid and higher elevated habitat found between 2,800 and 3,500 meters in the Andean Mountains.

The subtropical cloud forest is an important habitat for the Black-tailed Trainbearer because this is where they find areas of vertical vegetation, such as epiphytes, ferns, bromeliads, and heliconias, which are key in their foraging behavior.

Movements and Migration

Black-tailed Trainbearers are not migratory birds. They are in fact resident birds that are known to move vertically along the Andean Mountain range in response to food availability.

They will also move along a north-south axis in response to seasonal changes in flowers and resources. The birds prefer areas with abundant flowers, which allow them to maintain their energy demands.

During the breeding season, males will exhibit territorial behavior and defend their feeding territories in order to attract females.

Black-tailed Trainbearers also exhibit an interesting social behavior called “lek display”.

Lek is an area where males gather to engage in highly ritualized forms of competitive display. These displays can involve vocalization, movement, or even body position.

The lek display of the males is an important factor in attracting females for mating. One thing that may surprise some bird enthusiasts is that Black-tailed Trainbearers, like several other hummingbirds, are capable of torpor.

Torpor is a physiological state in which the bird lowers its body temperature and metabolic rate to conserve energy between active periods. This adaptation is especially important for hummingbirds, which have high energy demands due to their small size and fast metabolism.

In conclusion, Black-tailed Trainbearers have a fascinating set of behaviors that are adapted to their unique habitat in the Andean Mountains. Their foraging, territoriality, and lek display behaviors are just a few examples of their interesting natural history.

The birds prefer a high-altitude environment with plenty of vegetation, and are capable of moving vertically along the mountain range in search of food. While they are not migratory birds, they do move seasonally in response to changes in resource availability.

The adaptation of torpor also allows them to conserve energy during periods of rest. As we continue to learn more about the Black-tailed Trainbearer, these remarkable birds continue to remind us of the remarkable diversity and beauty of the bird life in the Andean Mountains.

Diet and Foraging

Feeding

The Black-tailed Trainbearer is a nectarivorous bird and their foraging behavior is adapted to search for flowers with a high energy content. They obtain nectar by hovering in front of flowers and inserting their long bills into the corolla to extract nectar.

The bird’s tongue is also an important adaptation in obtaining food. Its long, bifurcated tongue, is used to lap up nectar inside a flower’s corolla.

Black-tailed Trainbearers are also known to feed on insects and spiders, which are an essential source of protein and help supplement their nectar-based diet.

Diet

The Black-tailed Trainbearer’s diet varies according to the availability of flowers, nectar, and insects. During the breeding season, which coincides with the rainy season in the Andean Mountains, the bird’s diet shifts to flower species that are more abundant during this time and rich in sugar.

While they prefer flowers that are red or orange coloured, they will also feed from protruding or tubular-shaped flowers. During the dry season, they depend on nectar from species that are adapted to drier climates, such as ericaceous and bromeliad species.

Black-tailed Trainbearers are also known to feed on insects and spiders which are also essential for their survival.

Metabolism and Temperature Regulation

The Black-tailed Trainbearer has a unique metabolism and temperature regulation system. Due to their small size and high metabolism, hummingbirds have the highest energy demands of any bird species, requiring a significant intake of nectar each day.

However, their energy requirements are often limited by the capacity to extract nectar from flowers. To compensate for this, their metabolic rate is 15 times higher, and their body temperature is significantly higher than most other birds.

This means they have to consume up to eight times their body weight in nectar and insects each day to maintain their high metabolic rate and body temperature.

To reduce energy expenditure, the Black-tailed Trainbearer uses torpor, a state of regulated hypothermia, to enter into a state of reduced metabolic activity.

This is an essential adaptation as nectar-rich flowers may be scarce and food may be limited or inaccessible. During torpor, oxygen consumption rates decrease by more than 90% and body temperature lowers until energy rules are restored.

Sounds and Vocal Behavior

Vocalization

The Black-tailed Trainbearer has a complex vocal behavior, especially during the breeding season. The birds use their vocalizations during courtship, territory, and communication with their mates.

The males have a complex vocal repertoire with songs consisting of both songs and calls. The songs are complex, and interestingly, they are also shared substrates amongst members of the same species.

Also, the males have a distinctive call that they frequently use to communicate with mates and during flights. The calls have different tonal qualities and are often used as an alarm call.

In addition, the birds have a low volume “chip” sound, which they use very often during foraging or while in flight.

The females also sing, but their voice is much softer and quieter.

The females have a mating call, which is a soft tinkling sound that is difficult to hear, but always accompanied by the striking visual displays of the males during courtship display. The call acts as a cue for the males to display their energetic and aggressive courtship behavior.

During the breeding season, the combination of song, calls, and visual displays combine to form a complex system of communication for the species. In conclusion, Black-tailed Trainbearers have a complex set of behaviors that are intricately adapted to their habitat in the Andean Mountains.

Their diet is primarily based on nectar but insects and spiders are also important sources of protein. Their unique metabolism and temperature regulation system help to maintain high energy demands, while torpor allows them to conserve energy during periods of rest.

Vocal communication plays an essential role in their social interactions, especially during the breeding season. Their complex vocal repertoire and visual displays are an essential component in attracting mates and establishing territory.

Behavior

Locomotion

The Black-tailed Trainbearer is an active bird that hovers when feeding or flying. They are also known to perch on twigs and branches, and to fly short distances to chase others out of their territory.

They can fly up to 60km/h, which is relatively fast for such a small bird. They have strong, short legs and feet, which are adapted for perching on thin branches and leaves.

Self Maintenance

Black-tailed Trainbearers maintain their feathers with their bills by preening. Preening is essential for maintaining waterproof feathers and restoring its iridescent coloration.

Feathers are very important to birds as they are an essential feature in flight, insulation, and communication.

Agonistic Behavior

The Black-tailed Trainbearer is particularly aggressive during the breeding season when they defend their feeding territories to attract females. Males are highly territorial and engage in agonistic behaviors such as chasing, fighting, and posturing displays.

Posturing involves aggressive displays such as head-bobbing, wing-flashing, and tail-spreading. During posturing, the birds move around their perches to display their bright feathers, vocalize, and warn intruders to stay away from the territories.

Sexual Behavior

During courtship, males engage in highly energetic displays, called Lek displays, which involve aggressive territorial posturing, vocalizations, and wing displays. After these displays, females choose their mates and initiate the process of mating.

The male’s breeding plumage of brilliant green is an essential feature in attracting females for mating. The pairing of the two sexes is not permanent, as the birds are non-migratory, and pair only for the breeding season.

Breeding

The breeding season for Black-tailed Trainbearers coincides with the rainy season in the Andean Mountains, between October and April. During the breeding season, males establish territories in areas with abundant flowers, which attract females for mating.

The female lays a clutch of two eggs, which are incubated by the female alone for around 17 to 18 days. Upon hatching, the chicks are born blind and naked.

The male provides nectar from his territory to the female, which is used to feed the chicks. After about 15 to 20 days, the chicks are ready to leave the nest and become fledglings.

The fledglings continue to depend on their parents for food, and follow them in their foraging excursions.

Demography and Populations

The Black-tailed Trainbearer is found throughout the Andean Mountains, and it has a relatively stable population at the moment without any major threats. However, habitat loss due to deforestation has caused some concerns for the species.

It is restricted to humid forested areas where it feeds on nectar, and has undergone fragmentation of its habitat due to the increasing human interference in the Andean region. The species has also been impacted by illegal trade of bird feathers used in traditional cultural celebrations.

There are currently no conservation programs designed specifically for the Black-tailed Trainbearer, but it is believed that maintaining its habitat will ensure its continuity for future generations.

In conclusion, the Black-tailed Trainbearer possesses a range of interesting behaviors including aggressive territorial posturing, hovering and rapid flight, and self-maintenance through preening.

During the breeding season, males engage in complex vocal and visual displays to attract females. The species has a stable demography and population status currently, but is threatened by habitat loss due to deforestation.

It is believed that maintaining the Andean ecological system will ensure the continuity and conservation of the Black-tailed Trainbearer. The Black-tailed Trainbearer is a fascinating species of hummingbird that inhabits the Andean Mountains in South America.

Through detailed analysis, we have explored its physical characteristics, behavior, foraging habits, mating behavior, and populations. The Black-tailed Trainbearer has a unique set of adaptations in its habitat and behaviors that allow it to thrive in the challenging mountainous terrain.

Despite facing pressure from deforestation and the illegal trade of bird feathers, its populations remain stable. The significance of studying the Black-tailed Trainbearer and its Andean habitat exempl

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