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Majestic and Mysterious: All You Need to Know About the Buffy Fish-Owl

The Buffy Fish-Owl, also known as the Ketupa ketupu, is a magnificent bird of prey that can be found in the tropical regions of Southeast Asia. This bird is a majestic sight to behold, with its beautiful brown and grey feathers and striking yellow eyes.

In this article, we will delve into the identification, plumages, and molts of this fascinating bird species.


The Buffy Fish-Owl is a large bird, measuring about 50-60 cm in length, with a wingspan of about 125-140 cm. Its overall coloration is a uniform ochre-brown, with irregular barring on its underparts.

It has large yellow eyes while its facial disk is cream-colored with a brown border. Its beak is large and black, and its feet are feathered up to the talons.



During daylight hours, the Buffy Fish-Owl may be seen roosting on a branch or tree stump. The birds rounded head, large size, and prominent ear tufts are distinguishing characteristics.

The Buffy Fish-Owl displays a strange habit of raising one foot while perched, which may be particularly visible while perching on overhead wires near fishing areas. Another identifying feature is the bird’s low, hooting call.

Similar Species

The Buffy Fish-Owl’s appearance and call may be compared with the Tawny Fish-Owl, but the latter’s facial discs have orange-red eyes with a rufous-tinted beak, and the breast and belly are streaked rather than barred. The Buffy Fish-Owl is also similar to the Brown Wood-Owl, which has an overall rust-colored plumage with white streaks below.

However, the Buffy Fish-Owl is larger, and its head is more rounded with large yellow eyes.


Buffy Fish-Owls exhibit a distinctive head and upper body with a uniform tawny-brown coloration while the underparts and striated thighs have irregular brown and white barring. Juvenile birds have shorter ear tufts and chocolate-brown facial discs, in contrast to adults.


The Buffy Fish-Owl undergoes a complete molt once a year, with the primary molting season occurring from March through September. Males molt their feathers between late March and early June, while females are four to six weeks later.

The Buffy Fish-Owl follows a different molt pattern than most other owls, in which the primaries are molted at once, followed by the secondaries, and eventually ending with the tail. As a result, the bird goes through two different sets of flight feathers during the year, which could affect its flying ability briefly.


In this article, we’ve learned about the Buffy Fish-Owl, its identification features, similar species, plumages, and molts. This bird, with its stunning appearance and intriguing behavior, is a treasured species in the habitats where it lives.

, as the article will end with the final section on historical changes to distribution.

Systematics History

The Buffy Fish-Owl, also known as Ketupa ketupu, has been a subject of taxonomic debate for decades. Initially, it was classified under Strix and Bubo genera, before being placed under Ketupa.

DNA studies revealed that it is closely related to the eagle-owls, resulting in the recent classification into its own genus.

Geographic Variation

The Buffy Fish-Owl is found in tropical Southeast Asia, inhabiting mangroves, swamps, and rivers located within primary forests. This bird species is found across Indonesia, Malaysia, Thailand, Cambodia, Vietnam, and the Philippines.

Its range includes Sumatra, Borneo, the Malay Peninsula, Java, Bali, Luzon, Mindoro, Busuanga, Calauit, and other Philippine islands.


Ketupa ketupu has at least four recognized subspecies. According to the IOC, they consist of Ketupa ketupu ketupu, Ketupa ketupu microptera, Ketupa ketupu nudipes, and Ketupa ketupu manadensis.

– Ketupa ketupu ketupu: this subspecies is the nominal form. It is found in Sumatra, Borneo, and Java.

– Ketupa ketupu microptera: known as the Philippine Buffy Fish-Owl; this subspecies inhabits the Philippine islands. Its wings are shorter than the nominate subspecies.

– Ketupa ketupu nudipes: the Malayan Buffy Fish-Owl, the birds in Peninsular Malaysia and Thailand falls into this subspecies. It has longer and stronger legs than the others.

– Ketupa ketupu manadensis: this bird is found in northern Sulawesi and the small island of Peleng. It resembles K.

k. microptera, although it has a slightly larger and paler beak.

Related Species

The Buffy Fish-Owl is most closely related to the fish-eagle owls of the genus Bubo. Among them, it is most similar to the Brown Fish-Owl from South Asia and the Tawny Fish-Owl found in Southeast Asia.

The Brown Fish-Owl (Bubo fisheri) is distributed from the eastern Himalayas to Southeast Asia. It is larger than the Buffy Fish-Owl, has rusty-brown underparts, and white streaks on the chest and belly.

The Tawny Fish-Owl (Bubo flavipes) is a similar-looking bird but slightly smaller than the Buffy Fish-Owl. Its facial disk and underparts have a rust-colored tinge, which gives a subtle contrast to its barred breast and belly.

This bird species is found in the Indian subcontinent, Burma, Indochina, and southern China.

Historical Changes to Distribution

The primary habitat of the Buffy Fish-Owl is constantly threatened by human activities such as logging and conversion of forests into agricultural lands. The clearance of forested estuaries and conversion of mangroves to aquaculture ponds also pose an additional challenge.

In some areas such as Borneo, where the forest has been disturbed and fragmented, it is unclear whether the population decline is due to habitat loss or hunting. Nevertheless, populations remain intact across most of its range.

Despite the historical impact of habitat destruction, there has been some good news for the Buffy Fish-Owl. For instance, the species has been reported to thrive in the Tanjung Puting National Park in Indonesia, where bamboo thickets and riverine forests provide optimal nesting habitats.


The Buffy Fish-Owl has undergone various taxonomic reclassifications over the years due to DNA studies. The geographic variation in their range has resulted in four recognized subspecies.

Historical changes in distribution have resulted from habitat destruction, while habitat conservation has led to the species thriving in specific areas. The Buffy Fish-Owl is a species whose survival is dependent on habitat conservation, and it remains imperative to balance human activities with conservation.

, as the article will end with the final section on movements and migration.


The Buffy Fish-Owl is a species that is adapted to living in freshwater habitats like swamps, mangroves, and tropical forests with flowing water bodies. These birds are commonly found near rivers, streams, or estuaries.

In particular, they prefer habitats that are well-shaded under the canopy of trees that have broad riverbanks. This bird species is an apex predator and is considered a keystone species in its ecosystem.

They are at the top of the food chain and play a vital role in regulating the population sizes of prey species like fish, reptiles, and crustaceans. An essential feature of its habitat is that the water bodies remain unpolluted since they are an essential source of its food.

The air, sediment, and water quality should remain uncompromised to guarantee a sufficient number of fish for these birds.

Movements and Migration

Most individuals of this species are non-migratory and remain territorial throughout the year. While they don’t migrate, some might disperse short distances to ensure mates are found in nearby territories.

Vagrants can also be observed over long distances outside their range. Young birds are occasionally displaced from their breeding areas, leading to what looks like a seasonal southward wander in Malaysia.

That said, it’s unclear whether this behavior is a response to weather or habitat availability. Recent research has shown that the Buffy Fish-Owl has the ability to move across territories, sometimes over vast spaces.

The study, conducted in the Philippine Islands, involved capturing and radio-tagging Buffy Fish-Owls in various locations. They were monitored, and their movements were recorded.

The researchers discovered that the birds had a broader home range than initially thought. The species’ capability to move from one territory to another is essential for future genetic diversity since dispersed individuals can mate with those in other territories, leading to better genetic fitness and resistance to inbreeding.

The Birds in Sumatra, Indonesia, were observed to avoid areas of human activity, while the activities of human settlements in certain regions have influenced some territorial movements in these birds. Climate change could have an impact on the habitats of the Buffy Fish-Owl, causing a shift in the quality and proximity of freshwater ecosystems.

This could cause changes in this species’ behavior and range. Conservation measures to guarantee the long-term survival of this species should prioritize the protection and maintenance of its critical habitat.


The Buffy Fish-Owl’s habitat is critical to its survival, and these birds are adapted to living in freshwater habitats. Most individuals remain non-migratory and territorial throughout the year.

However, some observations suggest that the species may have the ability to move across territories to mate with dispersed individuals. Human activity and climate change may affect these birds’ habitats, so there is a necessity to maintain and protect their habitats to ensure their survival.

, as the article will end with the final section on sounds and vocal behavior.

Diet and Foraging


The Buffy Fish-Owl is a nocturnal hunter that feeds primarily on fish, with other prey making up a small part of its diet. It hunts by flying low over the water surface, detecting fish through the use of specialized hearing.

Once it identifies a target, it swoops down and snatches the fish from the water’s surface using its sharp talons. The bird will then fly back to a perch to eat its prey.

Some researchers have documented these owls using the same hunting perches repeatedly, indicating a degree of site fidelity.


Fish are the primary food of the Buffy Fish-Owl, and its choice of prey varies based on the fish’s availability and size. In some regions, it feeds on catfish, while in other areas, it mainly feeds on tilapia.

Studies have shown that fish weighing between 50-300g are preferred, but the Buffy Fish-Owl has also been observed to take fish weighing more than a kilo. Besides fish, other prey species make up less than 5% of their diet, with crabs and small crustaceans being the most frequent.

To a lesser degree, they also prey on frogs, lizards, snakes, and small mammals.

Metabolism and Temperature Regulation

Owls are known for being able to maintain a high body temperature of about 40C, even in cold environments. The Buffy Fish-Owl’s metabolism plays a critical role in regulating its body temperature.

It has a high metabolic rate which increases during the night when it’s active, and reduces during the day when it’s resting. Upon capturing a fish, the bird uses its sharp talons to hold the wriggling prey firmly while tearing off chunks of meat.

This hunting and feeding process demands a lot of energy, hence the high metabolic rate.

Sounds and Vocal Behavior


The Buffy Fish-Owl is not only known for its distinctive appearance but also for its vocalizations. It has a unique series of hoots, starting with two low-pitched hoots, a higher-pitched hoot in the middle, and two more low-pitched hoots at the end.

The first two hoots are quieter than the middle and tail-end hoots. The call of the Buffy Fish-Owl is usually heard at night, when it is most active.

The call is used to communicate with others of its species and mark territories. Vocalizations are also useful for attracting a mate and signaling aggression to potential competitors.

Males tend to have a different hoot sequence, and the pitch of their hoots tends to be higher than females. Researchers believe that the differences in hoots between the sexes are due to hormonal factors.

Besides its typical hoots, the Buffy Fish-Owl also produces a range of other vocalizations, including barks and growls. These calls are not well understood yet but could be used for communication with other species or during conflict situations.


The Buffy Fish-Owl is a nocturnal hunter that feeds mainly on fish, while other prey such as crustaceans and small mammals make up less than 5% of its diet. The bird has a high metabolic rate that enables it to regulate its body temperature in cold environments.

The Buffy Fish-Owl is a vocal bird known for its distinctive hoots and complex call sequences that allow it to communicate with others of its species and mark territories. The calls and vocalization of the Buffy Fish-Owl are still being studied, and there is more to learn about their significance.

, as the article will end with the final section on demography and populations.



The Buffy Fish-Owl has a unique and specialized hunting technique that requires it to fly low over the water surface and grab fish with its talons. However, besides flying, these owls can also climb tree trunks, branch-hop, and walk along the ground, but they rarely do so.


Like most birds, the Buffy Fish-Owl spends a significant amount of time preening, which involves the cleaning, maintenance, and arranging of feathers. They use their beak to remove dirt or debris from their feathers, making them clean, glossy, and beak their claws to sharpen them.

Agonistic Behavior

Agonistic behavior is common among Buffy Fish-Owls, particularly where territories overlap, which happens occasionally. They display different types of agonistic behavior, including vocalizing, bill-snapping, and talon slashing, which are primarily used to ward off intruders.

Sexual Behavior

The Buffy Fish-Owl is monogamous, meaning that birds pair for life. However, some cases have been documented where a male may take on another mate if the original mate dies.

This species reaches sexual maturity between one and two years of age.


Buffy Fish-Owls breed seasonally, dependent on food availability, and sometimes even changes in climate patterns.

Breeding typically takes place between November and March.

The female constructs a simple nest using sticks and leaves in a tree cavity located near large bodies of water. The female generally lays a clutch of two eggs, which she incubates for about 35 days while the male provides for her and protects the nest.

After hatching, both the male and female help care for the young. The young fledge at around 50 days and leave the nest at approximately 2-3 months.

Demography and Populations

Buffy Fish-Owl populations overall remain stable, which is indicative of the bird’s adaptability to a range of freshwater habitats. The species is considered a species of least concern due to its broad range and the absence of any significant threat to its survival.

Despite its classification, the Buffy Fish-Owl is affected by habitat loss, wetland drainage, and over-fishing of rivers and streams. In the past, habitat destruction caused by commercial and developmental projects in the Philippines where they are endemic was a significant threat.

The situation has improved, though, with conservation efforts focusing on protecting its habitat and promoting breeding programs. In some countries, the Buffy Fish-Owl is restricted to protected areas, and further conservation efforts need to be implemented to conserve their habitat.

It is essential that further studies continue to determine the behavior, population, and distribution of the Buffy Fish-Owl and the long-term effects of habitat destruction, climate change, and human activities.


The Buffy Fish-Owl exhibits unique behavior through its specialized hunting techniques, including flying low over the water surface to catch fish with its talons. They maintain good self-hygiene by preening, sharpening their beaks, and claws.

These birds display agonistic behavior and are typically monogamous, with breeding occurring seasonally between November to March. Despite its classification as a species of least concern, populations of Buffy Fish-Owls may be affected by habitat loss, wetland drainage, and over-fishing of rivers and streams.

Further conservation efforts should prioritize safeguarding the species’ habitat to maintain its populations. The Buffy Fish-Owl is a magnificent bird of prey that inhabits freshwater habitats across tropical Southeast Asia.

This owl species has distinctive traits, including a unique hunting technique, notable vocalizations, and monogamous mating behavior. It is also affected by habitat destruction, climate change, and human activities.

Despite these challenges, Buffy Fish-Owl populations remain stable, indicating its adaptability to its ecosystem. The significance of these findings lies in prioritizing habitat conservation and implementing further research to understand the behavior, populations, and distribution of this species, allowing us to ensure their survival in the long-term.

As keystone species, Buffy Fish-Owls play a critical role in

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