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10 Fascinating Facts About the Elusive Sabah Partridge

If you are an avid birdwatcher or just someone who appreciates the beauty of nature, the Sabah Partridge, Tropicoperdix graydoni, is a bird species that you should know about. This small bird native to Borneo is known for its striking plumage, unique call, and elusive behavior.

In this article, we will explore the identification, plumages, and molts of the Sabah Partridge, along with some similar species.

Identification

Field Identification

The Sabah Partridge is a small bird, measuring about 28-29 cm in length. It has a rounded body, short wings, and a fan-like tail.

The male and female birds have distinct plumages, making it easy to identify them in the field. The male birds have dark blue-gray feathers on the head and upperparts, with a reddish-brown collar around the neck.

The underparts are creamy-white, and the flanks are chestnut-brown. The male birds also have a distinctive black band on the throat.

The female birds are similar in size but have a duller coloration. They have brownish-gray feathers on the head and upperparts, with a pale buff collar around the neck.

The underparts are buff-yellow, and the flanks are rufous-brown. The female birds do not have a black throat band.

Similar Species

The Sabah Partridge can be confused with some other partridge species, such as the Chestnut-necklaced Partridge (Arborophila charltonii) and the Ferruginous Partridge (Caloperdix oculeus). However, the Sabah Partridge has distinct features that set it apart from these species.

The Chestnut-necklaced Partridge has a distinct chestnut-colored neck collar, while the Ferruginous Partridge has a rusty-brown back and flanks. The Sabah Partridge also has a unique call that can help in its identification.

Plumages

The Sabah Partridge has three plumages: juvenile, basic, and alternate. The juvenile birds have a duller coloration than the adult birds, with brownish-gray feathers on the head and upperparts, and buff-yellow underparts.

The basic plumage is worn by the adult birds from late summer to early winter. It is a simpler version of their alternate plumage, with less distinct markings and a duller coloration.

The alternate plumage is worn by the male birds during the breeding season, which begins in late winter. The male birds undergo a transformation, with their blue-gray feathers becoming brighter and more iridescent, and the reddish-brown collar becoming more prominent.

The black throat band also becomes more distinct. The female birds do not undergo such a transformation, but they do have a slight change in their plumage during the breeding season.

Their collar becomes more pronounced, and their flanks become brighter.

Molts

The Sabah Partridge has a complete molt once a year, which begins after the breeding season and before the winter migration. During this molt, the birds replace all of their feathers, including those on the wings and tail.

Conclusion

The Sabah Partridge, Tropicoperdix graydoni, is a unique bird species with striking plumage and elusive behavior. Its distinct features make it easy to identify in the field, and its plumages and molts add to its intrigue.

By learning more about this bird, you can appreciate the beauty and complexity of nature.

Systematics History

The Sabah Partridge, Tropicoperdix graydoni, belongs to the family Phasianidae, which includes pheasants, quails, and partridges. It was first described by N.H. Gurney in 1896 and was initially placed under the genus Arborophila.

However, molecular and morphological studies have shown that Tropicoperdix is a distinct genus from Arborophila, and the Sabah Partridge is one of the four species under this genus.

Geographic Variation

The Sabah Partridge is endemic to the island of Borneo, which is divided between Malaysia, Indonesia, and Brunei. This bird species is found in the mountainous regions of Sabah, which is located in the northern part of Malaysian Borneo.

The distribution of the Sabah Partridge is limited to the highlands, where the climate is cooler and wetter. It is found in montane forests and bamboo thickets at elevations between 900 and 2300 meters above sea level.

The habitat requirements of this bird species make it vulnerable to habitat loss, especially due to deforestation and conversion of land for agriculture.

Subspecies

There are two recognized subspecies of the Sabah Partridge: T. g.

graydoni and T. g.

lowi. The subspecies T.

g. graydoni is found in the central and southern parts of Sabah, while T.

g. lowi is found in the northern part of Sabah and the adjacent part of Kalimantan, Indonesia.

The two subspecies are similar in appearance, but they differ in their vocalizations. The lowland partridge, T.

g. lowi, has a lower-pitched and slower-paced call than the highland partridge, T.

g. graydoni.

Genetic studies have also shown that there are genetic differences between the two subspecies, which supports their distinct classification.

Related Species

The genus Tropicoperdix has four species, namely Tropicoperdix charltonii, Tropicoperdix chloropus, Tropicoperdix dixoni, and Tropicoperdix henrici. These species are found in different parts of Southeast Asia.

The Chestnut-necklaced Partridge (Tropicoperdix charltonii) is found in peninsular Thailand, Peninsular Malaysia, Sumatra, and Borneo. It has a chestnut-colored neck collar and is larger than the Sabah Partridge.

The Green-legged Partridge (Tropicoperdix chloropus) is found in peninsular Thailand, Sumatra, and Borneo. It has green-colored legs and is smaller than the Sabah Partridge.

The Bornean Crested Fireback (Tropicoperdix dixoni) is found in the mountainous regions of Sarawak and Kalimantan, Indonesia. It has a striking crest on its head and is larger than the Sabah Partridge.

The Creasted Partridge (Tropicoperdix henrici) is found in the southern Philippines. It has a distinctive crest on its head and is larger than the Sabah Partridge.

Historical Changes to Distribution

The Sabah Partridge has a limited distribution, and its population is threatened by habitat loss. The habitat of this bird species has been affected by deforestation, land conversion for agriculture, and logging.

Historically, the distribution of the Sabah Partridge was more widespread than it is today. Fossil records have shown that this bird species was once found in the lowland forests of Sabah.

However, the expansion of agriculture and logging in the lowlands has led to the loss of its habitat, which has restricted its current distribution to the highlands.

Conservation efforts, such as protected areas, have been established to conserve the remaining habitat of the Sabah Partridge. These efforts are crucial in ensuring the survival of this endangered bird species.

Conclusion

The Sabah Partridge, Tropicoperdix graydoni, is a unique bird species that is endemic to the island of Borneo. Its limited distribution and habitat requirements make it vulnerable to habitat loss, which has restricted its current distribution to the highlands of Sabah.

The two recognized subspecies of this bird species are similar in appearance but differ in their vocalizations and genetics. The genus Tropicoperdix has four species, which are found in different parts of Southeast Asia.

The historical changes in distribution of the Sabah Partridge have been driven by habitat loss due to deforestation, land conversion, and logging.

Conservation efforts are necessary to ensure the survival of this endangered bird species.

Habitat

The Sabah Partridge is an endemic bird species to the island of Borneo and is mainly found in Sabah’s mountainous regions. This bird species prefers to live in mountainous forests and bamboo thickets.

The bird is well adapted to living in the highlands where the climate is cooler and wetter than other areas in Sabah. It has been recorded at elevations of between 900 and 2300 meters above sea level.

The Sabah Partridge is monogamous and creates pairs that share a territory. The Sabah Partridge shares its habitat with other bird species like the Everett’s Thrush, Bornean Whistling Thrush, Blue-banded Pitta, and Bornean Treepie.

These birds are known to have overlapping territories or habitats.

Movements and Migration

The Sabah Partridge is a non-migratory bird species, which means it doesn’t undertake long-distance movements or seasonal migration. As a resident bird species, its movements are usually limited to short distances within its habitat to find food, water, or breeding territories.

The bird species has been observed to move in pairs during courtship, but afterward it remains in its territory.

However, the Sabah Partridge does undertake local movements within its range in response to weather and food availability.

For example, in the face of climate changes or habitat alterations, birds may move from one area to another to find a more favorable environment. During the breeding season, the male birds become more territorial, and their mating behavior changes; they become more aggressive, and their territorial claim expands.

The male’s mating attempts include perching at high points or in trees to attract a female partner with their calls. Male birds can also be seen performing courtship displays such as fanning out their tails and puffing up their chest feathers.

Breeding

The breeding season of the Sabah Partridge is from December to June, with most activity occurring between January and April. During the breeding season, this bird species becomes more aggressive and territorial, with males fighting to gain access to females.

Sabah Partridges are monogamous and form mating pairs within their territory. The pair remains together throughout the breeding season, and the male birds will defend the area from other males to protect their female partner.

The nest of the Sabah Partridge is typically a shallow depression on the ground, which is lined with plant materials, leaves, and grass. The female bird lays a clutch of two or three cream-colored eggs, which are incubated for around 18-20 days.

Both male and female birds share the responsibility of incubating the eggs. After hatching, the chicks become fully developed and are able to follow their parents within a few hours.

The chicks feed on insects and other invertebrates during the early stages of their development and later move to a diet consisting of seeds, fruits, and plants.

Conservation

Sabah Partridge is listed as an endangered species under the IUCN Red List due to habitat loss. Deforestation and land conversion for agriculture are the main threats to the survival of this bird species.

Conservation initiatives have been implemented to protect its habitat. These initiatives aim to increase native forest cover, regulate logging, and manage areas for sustainable agriculture to minimize the impact on the bird species’ survival.

Conclusion

The Sabah Partridge is an endemic bird species to the island of Borneo and is mainly found in Sabah’s mountainous regions. This bird species prefers to live in mountainous forests and bamboo thickets, and it is well adapted to living in the highlands where the climate is cooler and wetter than other areas in Sabah.

The Sabah Partridge is a non-migratory bird and is a resident in its forest habitat. During the breeding season, males become more territorial in courtship behavior.

Conservation initiatives aim to protect its habitat and increase native forest cover, manage areas for sustainable agriculture and regulate logging. These efforts are crucial in ensuring the survival of this bird species, listed as endangered under the IUCN Red List.

Diet and Foraging

Feeding

The Sabah Partridge is an omnivorous bird species, feeding on a variety of plant and animal material. The bird species has been seen to feed from both the ground and at low heights on vegetation, making it difficult for predators to spot it.

The Sabah Partridge’s feeding behavior changes depending on the availability of food. The bird feeds on berries, fruits, seeds, and insects found in its habitat.

During the breeding season, the bird species has been noted to shift its diet towards high-protein food sources, such as caterpillars and snails, to provide adequate nutrients for its growing young birds.

Diet

The Sabah Partridge’s diet is composed of a broad range of plants and animals. The bird species feeds on fruits, berries, and seeds.

Its diet is also supplemented with invertebrates, including insects, larvae, and worms. Feeding on insects and other invertebrates leads to the provision of higher protein levels, which are important for their survival and growth rates.

The bird species forages mostly on the ground by scratching the surface to uncover hidden food items. When feeding on fruits and vegetation, it uses its beak to cut or pluck the items while perched on the plant’s branches.

The feeding behavior of the Sabah Partridge aids in seed dispersal, improves soil quality, and contributes to the maintenance of biodiversity.

Metabolism and Temperature Regulation

The Sabah Partridge maintains optimal body temperatures in its cool and damp habitat. Its metabolic rate is adapted to match the environment’s temperature variation by reducing metabolic activity during resting and increasing it when active.

The bird species also uses external factors such as shelter and direct sunlight to regulate its temperature. During cold environments and at night, the Sabah Partridge reduces heat loss from its body by fluffing its feathers, which traps air and insulates it.

The bird species also has an adaptation in its toes that allows it to hang onto branches and perch with greater control, allowing it to maintain its balance during feeding and perching.

Sounds and Vocal Behavior

Vocalization

The Sabah Partridge’s call is an essential communication tool used for socialization, territorial defense, and mate attraction. The bird species vocalizes frequently throughout the day, often during the early morning and late afternoon.

Its call is a series of whistled notes, starting with a clear whistle and ending with a low-pitched churring sound. The male bird’s vocalization becomes more frequent during the breeding season, becoming louder and more intricate during courtship.

During this period, the male birds use call notes and display behavioral signals to attract a female partner. The vocalization also has a territorial function, with males often vocalizing their ownership over the territory to protect it from intruders.

The vocalization of the Sabah Partridge is unique and specific to its species. This vocalization is essential for communication, mate attraction, and territorial defense, contributing to the preservation of this endangered bird species.

Conclusion

The Sabah Partridge is an omnivorous bird species with a broad diet and foraging behavior. Its feeding behavior contributes to seed dispersal, biodiversity, and soil quality in its mountainous forest habitat of Sabah.

The bird species maintains its optimal body temperature through metabolic regulation and adaptation to external factors, such as direct sunlight and the use of natural insulation.

The bird’s vocalizations are a vital tool for socialization, territorial defense, and mate attraction.

Its calling behavior becomes more frequent and intricate during the breeding season, with males using calls and behavioral signals to attract a female partner. Overall, these adaptations, behaviors, and vocalizations add to the unique features of the Sabah Partridge and emphasize the importance of conservation initiatives to protect this endangered bird species.

Behavior

Locomotion

The Sabah Partridge has a ground-dwelling and arboreal locomotion behavior. This bird species is comfortable traveling on the ground, where it uses its short legs to move quickly and efficiently.

The bird also has the ability to climb trees and hop from branch to branch with accuracy and balance. When perched on a branch, the Sabah Partridge often uses its claws to hold on tightly, allowing it to maintain balance despite strong winds.

The bird species is also known to use its wings to balance and glide across small distances when moving from tree to tree.

Self Maintenance

The Sabah Partridge has a fastidious self-maintenance habit, which involves regular grooming, preening, and dust-bathing. The bird species is known to create shallow depressions in the ground where it takes dust baths to get rid of parasites, dirt, and excess oil from its feathers.

The bird species regularly preens and maintains its feathers, using its beak and tongue to remove dirt, oil, and loose feathers. The Sabah Partridge’s fastidious maintenance behavior contributes to the maintenance of optimal temperature regulation and waterproofing of its feathers.

Agonistic Behavior

The Sabah Partridge displays agonistic behavior in the context of territoriality and mating. During the breeding season, males defend their territories from other males by engaging in bouts of aggressive displays, including vocalization, feather puffing, and physical attacks.

The bird species is also known to engage in competitive behavior during foraging, especially when resources are scarce. This results in aggressive behaviors, such as pecking and chasing other birds out

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