Bird O'clock

10 Surprising Facts About Black-nest Swiftlets

Black-nest Swiftlet, scientifically known as Aerodramus maximus, is a species of swiftlet commonly found in the Southeast Asian region. These birds are known for their unique nest-building technique and their swift flight patterns.

In this article, we will explore the identification, plumages, and molts of this amazing bird species.


Black-nest Swiftlets are small birds that measure around 10-12 centimeters, with a wingspan of about 25 centimeters. They have a dark brown to black glossy plumage that appears to be iridescent in the sun.

Their wings are narrow and long, enabling them to fly fast and accurately. These swiftlets have a short and stubby tail with a slightly forked tip.



Identifying Black-nest Swiftlets can be challenging due to their similarity with other swiftlet species. They are similar in size and structure to Glossy Swiftlets but have a darker appearance.

Their call is a loud “cheeret, cheeret” sound, which can be easily recognized if you are familiar with their vocalization.

Similar Species

Several swiftlet species resemble the Black-nest Swiftlet, including the Glossy Swiftlet, Black-nest Swiftlet, and Mossy-nest Swiftlet. The Glossy Swiftlet has a dark blue-black plumage that appears glossier than the Black-nest Swiftlet.

The Black-nest Swiftlet has a shorter tail than other swiftlet species, while the Mossy-nest Swiftlet has a shorter wingspan and has a brownish plumage with black feathers on their throat.


Black-nest Swiftlets have a unique plumage with subtle variations. The juvenile birds have a fawn brown plumage, which gradually changes to a darker color as they mature.

Adult birds have a dark brown to black glossy plumage, which appears iridescent in the sunlight.


Black-nest Swiftlets undergo a complete molt usually once a year, where they replace all their feathers. Prior to molting season, these birds ingest a significant amount of nutrients and minerals, which ensure their feathers’ proper growth.

During the molting period, they become less active and prefer to roost in a safe and secure location. In conclusion, Black-nest Swiftlets are fascinating birds with an incredible unique nest-building technique and swift flight patterns.

Their unique plumage and identification can be challenging to observe, but with an eye for detail and experience with their vocalization, they can be easier to identify. Understanding their plumages and molt is vital to interpreting their lifecycle correctly.

Hopefully, this article has provided valuable insights into this incredible bird species.

Systematics History

The Black-nest Swiftlet, scientifically known as Aerodramus maximus, is a common swiftlet species found in Southeast Asia. The species was first described by John Edward Gray, an English Zoologist, in 1846.

Since then, many studies have been conducted in order to understand the taxonomy and evolutionary history of the Black-nest Swiftlet.

Geographic Variation

The Black-nest Swiftlet has a wide distribution range from the Andaman and Nicobar Islands in the Indian Ocean to the North Moluccas and South Sulawesi in the Pacific Ocean. The species occupies a broad range of habitats, including forests, cliffs, caves, and man-made structures such as buildings.


Based on the variations of physical features and geographic distribution, the Black-nest Swiftlet has various subspecies. The subspecies are classified based on the region they are found in, such as:

Aerodramus maximus sondaicus – Found in the southern regions of the Malay Peninsula, Sumatra, Java, and the adjacent islands.

Aerodramus maximus maximus – Found in the Andaman and Nicobar Islands. Aerodramus maximus fraterculus – Found in the southern regions of the Malay Peninsula and adjacent islands.

Aerodramus maximus perplexus – Found in the Sulu Archipelago in the southern Philippines. Aerodramus maximus littoralis – Found in the Nicobar Islands.

Aerodramus maximus forbesi – Found in the North Moluccas. Aerodramus maximus inexpectatus – Found in the Sula Islands in Indonesia.

Related Species

The Black-nest Swiftlet is one of the 27 species of swiftlets that belong to the genus Aerodramus. These species have similar morphological, ecological, and behavioral traits.

The genus consists of mainly three groups: the Black-nest Swiftlet group, the Cave Swiftlet group, and the Mossy-nest Swiftlet group. The Black-nest Swiftlet group consists of the following species:

– Black-nest Swiftlet – Aerodramus maximus

– Indian Swiftlet – Aerodramus unicolor

– Edible-nest Swiftlet – Aerodramus fuciphagus

– Mossy-nest Swiftlet – Aerodramus salangana

Historical Changes to Distribution

The Black-nest Swiftlet has undergone significant changes in its distribution range over time. The species was once abundant throughout its distribution range, but the bird’s populations have seen a marked decline in recent years.

This has been attributed to habitat loss, extensive exploitation of the bird’s nests, and human disturbance. In the 19th century, the Black-nest Swiftlet was prevalent in Penang, Malaysia, where it was used to produce bird’s nest soup.

However, the swiftlet population in the area declined drastically in the 20th century due to overexploitation. The same scenario was experienced in caves near Phuket, Thailand, where the population of the Black-nest Swiftlet decreased from millions to less than thousand birds.

In contrast, the Black-nest Swiftlet population has increased in urban areas such as Singapore, where they have adapted to the use of man-made structures such as buildings for roosting and nesting purposes. These birds can be seen nesting in the roofs of high-rise buildings in the city-state.

With the increasing awareness of the importance of conservation and sustainable development, concerted efforts have been made to improve the protection of swiftlet habitats and minimize exploitation. These conservation efforts aim to protect the Black-nest Swiftlet populations, while also ensuring the sustainable exploitation of the species for the production of bird’s nest soup.

Overall, the Black-nest Swiftlet remains an important species in Southeast Asia, with unique ecological and cultural significance. As such, efforts should be intensified to protect this remarkable species and ensure its survival for generations to come.


The Black-nest Swiftlet is a species that is highly adapted to life in caves and other dark, humid environments. These birds are found across a broad range of habitats, including forests, cliffs, caves, urban areas, and man-made structures such as buildings.

They are commonly found in Southeast Asian countries such as Indonesia, Thailand, Malaysia, and Singapore. The preferred habitat of the Black-nest Swiftlet is in underground caves or crevices.

These swiftlets build their nests out of a type of saliva that hardens and resembles white filaments shaped like shallow cups. The nesting materials provide the birds with some protection from the elements and predators.

Movements and Migration

Black-nest Swiftlets are non-migratory birds, meaning they stay in their range throughout the year. They can frequently be seen flying at high altitudes above their nesting site during the day and return in the evening to their roosts or nesting sites.

During the breeding season, the birds go through a complex courtship ritual, which involves flying in circles around their partners while making a loud clicking sound from their bills. These clicks, which sound like the clapping of one’s hands, can be heard from quite far away and are used as an audible attractant to the opposite sex.

Both sexes construct the nests but only the female incubates the eggs. Female swiftlets lay up to two eggs per clutch, which hatch within two weeks.

The young fledge when the nest material is thick enough for them to find a foothold. Although they are non-migratory birds, Black-nest Swiftlets can be seen moving around in response to seasonal changes in food availability.

During the rainy season, insects and other invertebrates become more abundant, which causes an increase in the swiftlets’ reproductive activity. Swiftlets usually forage during the day, using echolocation to locate prey and navigate through the dark environments where they feed.

Breeding activities are sensitive to disturbances. As a result, human activities near or within these feeding areas are discouraged to avoid disturbing daily movement patterns.

Unfortunately, human activities continue to negatively impact the Black-nest Swiftlet’s survival.

Conservation Measures

The Black-nest Swiftlet is important for both ecological and economic reasons. They contribute to insect control and provide valuable bird’s nests for consumption in some parts of Asia.

However, the population of the Black-nest Swiftlet is currently threatened by habitat destruction and exploitation for their nests, which have a high commercial value. The situation has become so severe that many countries have introduced legal measures to protect the species.

In response to these threats, many conservation efforts have been initiated to ensure their long-term survival. One of the efforts involves improving and protecting the habitats where the birds build their nests.

This includes monitoring the population, reducing human disturbance, promoting conservation education, and conducting scientific research. Efforts to protect the Black-nest Swiftlet populations involve collaboration between the government, local communities, industries, and non-governmental organizations.

The conservation efforts aim to balance the need for sustainable development with the conservation of the birds’ natural habitats. In conclusion, the Black-nest Swiftlet is an important species that plays a vital role in the ecosystem.

Although they are non-migratory birds, they move around in response to seasonal changes in food availability and other environmental factors. The bird’s survival is threatened by habitat destruction, human disturbance, and exploitation.

Efforts must be intensified to protect their habitats and promote conservation education to ensure that these birds survive and have a secure future.

Diet and Foraging


The Black-nest Swiftlet primarily feeds on small, flying insects such as termites, ants, flies, and moths. These swiftlets fly in a jagged pattern, catching their prey in mid-air.

Their flying style allows them to catch insects that may be too small to see or difficult to catch by other birds.


The Black-nest Swiftlet’s diet does vary depending on seasonal changes, food availability, and weather patterns. During the breeding season, females require higher amounts of protein to produce eggs, so the birds tend to feed more on insects with higher protein content.

In contrast, during non-breeding periods, they consume a broader range of insects, depending on their availability.

Metabolism and Temperature Regulation

Black-nest Swiftlets are endothermic, meaning they can regulate their body temperature through internal metabolic processes. These birds have a high metabolic rate and a body temperature of approximately 39 degrees Celsius, allowing them to maintain their body temperature in cold and low-temperature environments.

Sounds and Vocal Behavior


Black-nest Swiftlets have a unique vocalization that they use for communication, identification, and courtship rituals. The birds have several different calls, including a high-pitched, rapid, and repeated cheeret, cheeret sound.

This call is often used to signal to the other birds to follow the leader, as the swiftlets generally use echolocation to find their way in and out of their nests in complete darkness. Additionally, the repeated call may indicate courtship or territorial displays during the breeding season.

The birds also produce a clicking sound with their bills, which they use during courtship displays. During the breeding season, when males are competing for females, they will cling onto an object and make repeated clicking sounds to try to win over a female.

This sound is created by the swiftlet’s unique anatomy, which allows them to produce a loud and sharp sound by swiftly closing their beak. Black-nest Swiftlets also produce other calls, including aggression and alarm calls.

The aggression call is a harsh, scolding sound that is used when a bird feels its territory is being threatened. Meanwhile, the alarm call is a series of loud chirps, which can alert other birds in the area of an imminent risk or danger.


Black-nest Swiftlets are fascinating birds that are well-adapted to their unique lifestyle. They have a varied and complex diet, allowing them to maintain a high metabolic rate and regulate their body temperature in various environmental conditions.

These birds use their vocalizations for communication, identification, and courtship displays, with a unique sound that is produced by the swiftlet’s unique anatomy. Improving our understanding of the diet, foraging, regulation of body temperature, and vocal behaviors of the Black-nest Swiftlet is essential for conducting targeted conservation and management efforts to protect their populations and ensure their continued survival.



Black-nest Swiftlets are agile birds that can fly at high speeds and maneuver through small cracks and crevices in cave walls and other structures. They are also able to hover in place, which allows them to catch insects that may be out of reach of other hunting birds.

These swiftlets are highly adapted to flying, with their wings being elongated and narrow, allowing them to fly quickly and accurately.

Self Maintenance

Black-nest Swiftlets are highly social birds, and they exhibit cooperative behaviors when it comes to maintaining their nests and searching for food. Mutual preening and cleaning activities are often seen among swiftlets, where they use their bills to remove dirt and excess saliva from themselves.

They also maintain their nests regularly by adding new saliva to repair the cup-shaped nests.

Agonistic Behavior

Black-nest Swiftlets can exhibit aggressive behaviors when their territory is threatened or when they are in competition for a mate. They can attack other birds and animals that are seen as a threat, and this can be observed when a predator approaches a nesting site.

Sexual Behavior

Black-nest Swiftlets are monogamous, meaning that they mate for life. During the breeding season, males will try to attract females by flying around and making clicking noises with their beaks.

After the pair bonds and start to begin breeding activities, they will start to construct their nest together out of saliva, which is laid on top of each other’s saliva layers.


Black-nest Swiftlets breed seasonally and primarily in large, dark cave systems. During the breeding season, which begins around January to April, the male will try to attract a female by displaying or calling out with a high-pitched noise.

The birds will then construct their nest together on a cave wall or ceiling, using saliva as building material. After the nest is complete, the female will lay two eggs, which are incubated by both the male and female.

The incubation period lasts for approximately 20 days. After hatching, the young chicks are fed by both parents, with both male and female swiftlets contributing to their care and feeding.

The chicks fledge within about 35 days after hatching, but they remain close to the nest and are still fed by their parents for several weeks.

Demography and Populations

The Black-nest Swiftlet’s populations have faced several threats, mainly from habitat loss and over-exploitation from the bird’s nest industry. The nests are highly valued in Asian cultures and are commonly used in Asian cooking.

This has led to the Black-nest Swiftlet being listed as “vulnerable” under the International Union for Conservation of Nature Red List. Conservation measures to protect the species include habitat protection and regulation of the bird’s nest industry.

Many conservation organizations and governments are working together to ensure sustainable exploitation of the Black-nest Swiftlet. Other measures that have been put in place include the creation of protected areas where the Black-nest Swiftlets are found and the improvement of local communities’ awareness of the bird’s nesting behavior.

Studying the behavior, breeding patterns, demography, and population dynamics of the Black-nest Swiftlet is critical to the species’ conservation and management. As such, ongoing scientific research and monitoring are necessary to safeguard the Black-nest Swiftlet from decline and extinction and to ensure their continued survival for future generations.

In conclusion, the Black-nest Swiftlet is a fascinating bird species well-adapted to dark and humid environments, using its unique foraging behaviors, vocalizations, and breeding strategies to survive and thrive. The bird’s populations have been threatened by habitat destruction and exploitation, but various conservation measures are in place to protect them.

Studying the behavior, demography, and populations of Black-nest Swiftlets is critical in ensuring their viability and survival in the future. Effective conservation management strategies must be developed, and actions taken, to ensure that the Black-nest Swiftlet’s role in the ecosystem is preserved for generations to come.

Popular Posts