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Uncovering the Fascinating Behaviors of the Black-Eared Fairy: Hovering Agonistic Fights and Cooperative Breeding

Birds come in different shapes, sizes, and colors, making birdwatching a thrilling experience. One unique species of bird to watch is the black-eared fairy (Heliothryx auritus).

This stunning bird is native to Central and South America, found mostly in open forests, plantations, gardens, and parks. This article will highlight the black-eared fairy’s identification, plumage features, and molting process.


The black-eared fairy is an unmistakable bird with its distinguishing features. With a length of about nine centimeters and a weight of four to six grams, it is one of the tiniest bird species in the world.

It has a metallic green crown, back, and tail, a black mask on its face, and a creamy white belly. The birds get their name from the black ear patch behind their eyes and are predominantly green with white spots on their wings.



In the field, it is easy to confuse the black-eared fairy with other similar-looking hummingbird species. One of these is the green-crowned brilliant.

They share the same size, green back, and crown. However, the green-crowned brilliant looks much larger, with a more profound tail indentation, and has a less pronounced black eye mask.

Another species close in appearance is the violet-crowned woodnymph, which is more massive, has a more extended tail and a purple crown instead of green.

Similar Species

Other similar species are the green-bellied hummingbird and rufous-tailed hummingbird. The green-bellied hummingbird has a similar size, a green forehead, a pale buff belly, a less pronounced black eye mask, and lacks the black ear patch.

On the other hand, the rufous-tailed hummingbird has a more extended tail and a deeper iridescent coloring, particularly on the belly and throat.


As with most bird species, the black-eared fairy undergoes several plumage changes as it matures. It has a specific plumage that occurs during its juvenile stage, adult stage and breeding season.

Let’s break this down;

Juvenile Plumage: This is the plumage that the young black-eared fairy has when hatched. They have a duller overall coloration, and their markings are not as pronounced as the adults.

Adult Plumage: Once the juveniles fledge, their feathers start to take the hues of adult plumages. They acquire the signature green hues on their crown, back, and tail, a creamy white belly characterized by white spots on its wings, and the unmissable black mask.

Breeding Plumage: The breeding plumage of the black-eared fairy is characterized by elongated metallic green feathers on either side of the tail. These feathers are more iridescent in males than females, and their black ear patch is more distinct.


Molting is a natural process that most bird species undergo to replace old, damaged, and faded feathers. The black-eared fairy goes through a complete molt once every year and partial molts between breeding seasons.

During the complete molt, the birds lose their flight feathers all at once and take around three weeks to regrow. During the partial molt, they replace their body and contour feathers systematically before and after the breeding season.

In summary, the black-eared fairy is an incredibly unique bird species in Central and South America. Birdwatchers can quickly identify them through their striking green, black, and white plumage and black ear patch.

Despite their beautiful plumage, these tiniest birds in the world can be challenging to differentiate in the field, with other similar-looking hummingbirds present. Understanding their molting and plumage changes during their growth stages is a useful bird watching skill that helps in their identification.

The black-eared fairy (Heliothryx auritus) is a fascinating bird species that is native to the tropical regions of Central and South America. Its taxonomy has undergone numerous changes over the years, leading to a better understanding of its morphology, behavior, and genetic makeup.

In this article, we highlight the systematics history of the black-eared fairy, its geographic variation, subspecies, related species, and historical changes to distribution.

Systematics History

The black-eared fairy belongs to the family Trochilidae, the largest family of birds that includes over 300 species of hummingbirds. The first scientific description of the black-eared fairy was made by the French naturalist Louis Jean Pierre Vieillot in 1818.

He classified the species under the genus Trochilus, which was later renamed to Heliothryx in 1850 by the French ornithologist Charles Lucien Bonaparte. Its specific epithet “auritus” is Latin for “eared,” and describes the horizontal black ear patch behind the birds’ eyes.

Over the years, the black-eared fairy’s classification has undergone significant revisions. In the 19th century, the bird was classified as an insect-regulating bird and was often depicted in natural history illustrations as a bird that hunted insects in the air.

However, the observation and study of the birds’ behavior, ecology, and anatomy have improved over time, leading to a better understanding of its classification.

Geographic Variation

The black-eared fairy has a widespread distribution throughout Central and South America, including countries such as Columbia, Panama, Ecuador, Peru, and Brazil. Its geographic variation across different regions has led to the recognition of subspecies.


There are three recognized subspecies of black-eared fairy. These subspecies exhibit differences in plumage and size.

They are:

1. Heliothryx auritus auritus

This subspecies is found in northeastern South America, mainly in the Guianas, Suriname, and French Guiana.

It is the most distinct of the three subspecies, and its plumage is characterized by a metallic green crown, back, and tail with a black mask and a white belly. 2.

Heliothryx auritus warczewitzii

This subspecies is found primarily in northwestern South America, including Colombia, Ecuador, and Peru. It differs from the nominate subspecies by its slightly larger size and more prominent black ear patch.

3. Heliothryx auritus polytmus

This subspecies is found in northeastern South America, mainly in Brazil.

It differs from the nominate subspecies by its longer bill and its more extensive metallic green areas on its back and wings.

Related Species

The black-eared fairy belongs to the genus Heliothryx, which includes three other species. They are:


Green thorntail (Heliothryx auriculata)

This species is found in Ecuador and Peru and can be identified by its metallic green body and elongated central tail feathers. 2.

Black-throated mango (Anthracothorax nigricollis)

This species is found in Central and South America and is notable for its metallic green head, throat and back, and black mask. 3.

Black-bellied thorntail (Discosura langsdorffi)

This species is found in Brazil and is identified by its metallic green head, back, and tail, black belly, and white tail tips.

Historical Changes to Distribution

The black-eared fairy’s range has not changed significantly. However, its distribution has been affected by habitat destruction and fragmentation, primarily due to wildfires, deforestation, and urbanization.

These activities have led to a decline in population sizes and range contraction in some regions. Conservation efforts such as the establishment of protected areas and restoration of degraded habitats have helped mitigate some of these effects.

In conclusion, the black-eared fairy’s systematics history, geographic variation, subspecies, related species, and historical changes to distribution have undergone significant changes over the years, leading to a better understanding of its taxonomy, ecology, and behavior. Understanding the differences between subspecies and related species has helped in their identification, while conservation efforts continue to be crucial in their preservation.

The black-eared fairy (Heliothryx auritus) is a tropical bird species found in Central and South America. It is highly adapted to specific habitats, and its movements are influenced by factors such as food availability and breeding behavior.

In this article, we will explore the black-eared fairy’s habitat preferences and movements, including migration.


The black-eared fairy primarily occurs in tropical forests, shrublands, and gardens. They are commonly spotted in wet lowland and montane forests and are most abundant in old-growth forests with a dense understory.

These birds have also been observed in plantations, gardens, and parks, where there is food availability and proper cover. Black-eared fairies require specific microhabitats to survive, such as forest edges, gaps, and clearings.

They are also often seen in areas where flowering trees and bushes are in abundance, such as Heliconia and other plants of the order Zingiberales. This is because they feed on nectar and insects, and these plants provide their necessary nutrients.

Movements and


The black-eared fairy is not known to undertake long-distance migrations. However, it may have some movements influenced by breeding behavior and food availability.

Breeding movements: During the breeding season, males move to high-quality territories and defend these areas to attract females. The males select territories with resources such as food and suitable nesting sites.

Food availability movements: Black-eared fairies have also been known to move around in search of food following fluctuations in nectar availability. This occurs primarily between the wet and dry seasons when nectar supply varies in different habitats.

In addition to these movements, black-eared fairies engage in daily movements, such as foraging, which takes place in small territories close to their nesting sites. These small-scale movements are essential for both male and female black-eared fairies to acquire sufficient nutrients to sustain their energetic requirements.

Breeding Habits

The black-eared fairy’s breeding habits are highly influenced by its habitat and resource availability. Males defend territories that provide resources, and females select these males based on the quality of their territories.

In some instances, male black-eared fairies may defend territories with significant flower density, while others defend territories with higher numbers of treelets, suitable for nest building. The breeding season may occur several times throughout the year, and breeding activities vary depending on the region.

Black-eared fairies can either breed solitarily or in a cooperative fashion, where multiple individuals share a nesting site.


Black-eared fairies build tiny cup-shaped nests using materials such as lichens, spider webs, and plant fibers. The nest is usually attached to a thin branch, and the entrance faces downward, providing it with some protection against predators.

Females incubate the eggs, and both parents take turns feeding and attending to the nestlings.


The black-eared fairy is primarily a resident bird, and most populations are non-migratory. However, there have been some isolated reports of seasonal movements influenced by factors such as food availability and breeding behavior.

In Panama, for example, some individuals were observed to have migrated from the Pacific slope to the Caribbean lowlands during the dry season, probably in search of more abundant food sources. Such movements have been attributed to fluctuations in nectar availability and have been observed in other tropical hummingbird species.

Conversely, black-eared fairies in some regions may undergo altitudinal migrations, descending to lower elevations during the non-breeding season and returning to higher altitudes during the breeding season. Such migrations have been observed in other tropical bird species and are influenced by factors such as temperature and resource availability.

In conclusion, the black-eared fairy is a tropical bird species adapted to specific habitats, such as rainforests, shrublands, plantations, and gardens. Its movements are influenced by breeding behavior and fluctuations in nectar availability.

The black-eared fairy is primarily a non-migratory species with isolated reports of seasonal and altitudinal migrations. Understanding its habitat preferences and movements is crucial in conservation efforts aimed at preserving this unique species.

The black-eared fairy (Heliothryx auritus) is a tiny bird species that is popular among bird enthusiasts because of its remarkable plumage and unique behavioral patterns. In this article, we will explore the black-eared fairy’s diet and foraging behaviors, as well as its vocalizations.

Diet and Foraging


Black-eared fairies are primarily nectarivorous, meaning they feed on the nectar produced by flowers. They are also insectivorous, and they supplement their nectar diet with insects such as mosquitoes, gnats, and fruit flies.

They typically forage by hovering in front of flowering plants and inserting their long, slim beaks into the flower’s corolla, lapping up nectar with their tongues. Male black-eared fairies expend more energy and feed more often during the breeding season, as they need to defend territories and attract females.

Females, on the other hand, expend more energy during the incubation stage and thus have higher metabolic rates to cater to their energetic requirements.


Black-eared fairies feed on the nectar of various flowering plants such as Heliconia, Costus, and Thalia. They also feed on insects such as mosquitoes, gnats, and fruit flies.

Studies have shown that nectar provides black-eared fairies with the necessary carbohydrates and sugars to sustain their high metabolic rates. Insects, on the other hand, provide the necessary protein, vitamins, and minerals needed for the birds’ survival.

Metabolism and Temperature Regulation

Black-eared fairies have a high metabolic rate to cater to their energetic requirements. Their metabolism is so high that they require almost constant feeding to maintain their energy levels, especially during the breeding season.

In addition to their high metabolic rate, black-eared fairies regulate their body temperature through their behavior and physiology. They decrease their metabolic rate when temperatures are high, and they also take advantage of favorable environments such as microclimates within their habitat to regulate their temperature.

Sounds and Vocal Behavior


The black-eared fairy has several vocalizations used for communication, including songs, calls, and alarms. Vocalizations are important in breeding and defending territories.

Males use songs to attract females and defend their territories against intruders. Their songs are distinct from other hummingbird species and consist of a series of sharp, high-pitched notes that are repeated for several seconds.

Their songs can be heard up to 50 meters away and are often referred to as “chup, chup”notes. The female black-eared fairy uses vocalizations to communicate with her mate and offspring.

They have a shrill alarm call that is used to alert their mate and offspring of impending danger. The alarm call is similar to the sound of a chip or buzz and is used mainly to indicate the presence of predators or other threats.

In conclusion, the black-eared fairy is a unique bird species with peculiar diet and foraging habits. Their high metabolic rate requires almost constant feeding, and they supplement their nectar diet with insects.

Their vocalizations are an essential part of their communication, with males using songs to defend their territories and attract females, while females use shrill alarm calls to alert their mate and offspring of impending danger. Understanding the black-eared fairy’s vocalizations and foraging habits is key to better appreciating this tiny bird’s beauty and unique lifestyle.

The black-eared fairy (Heliothryx auritus) is a unique bird species with interesting behavioral patterns. In this article, we will explore the black-eared fairy’s behavior, including locomotion, self-maintenance, agonistic and sexual behavior.

We will also look into their breeding habits, demography, and populations.



The black-eared fairy moves primarily by hovering, flapping its wings up to eighty times per second with short intervals of gliding and flying. They are agile birds capable of moving in any direction, giving them an edge in foraging and evading predators.

Their aerial maneuverability is attributed to the unique shoulder joint that allows them to rotate their wings through a full circle.


Black-eared fairies practice self-maintenance behaviors such as preening, bathing, and sunning. Preening involves the birds cleaning their feathers with their beaks, ensuring they retain their iridescence and waterproofing their feathers.

Bathing and sunning are essential in regulating the birds’ temperature and keeping their feathers in excellent condition.

Agonistic Behavior

The black-eared fairy exhibits agonistic behavior towards other birds, especially during the breeding season, when males defend their territories aggressively. Agonistic behavior includes perimeter defense, where males fight and chase away intruders from their breeding territories.

In some instances, territorial disputes may escalate to physical fights.

Sexual Behavior

Black-eared fairies exhibit sexual dimorphism, where males have more distinct markings, and their feathers are more iridescent than females. Males typically defend territories to attract females.

When ready to mate, females approach the males’ territories, and if satisfied, they mate and create a nest.


Black-eared fairies breed semi-cooperatively, with males and females displaying cooperative breeding behaviors. Cooperative breeding behavior involves male helpers who assist in providing for the females during nesting, incubation, and brooding, primarily in cases where there is a high number of females requiring assistance.

Males construct nests using materials such as moss, leaves, and plant fibers and provide resources to the females such as nesting materials, and defend the nest from potential predators. Females lay two small white eggs

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