Swiftlet
Encyclopedia
Swiftlets are bird
s contained within the four genera
Aerodramus, Hydrochous, Schoutedenapus and Collocalia. They form the Collocaliini tribe
within the swift
family Apodidae. The group contains around thirty species mostly confined to southern Asia
, south Pacific islands, and northeastern Australia
, all within the tropical and subtropical regions. They are in many respects typical members of the Apodidae, having narrow wings for fast flight, with a wide gape and small reduced beak surrounded by bristles for catching insects in flight. What distinguishes many but not all species from other swifts and indeed almost all other birds is their ability to use a simple but effective form of echolocation
to navigate in total darkness through the chasms and shafts of the cave
s where they roost at night and breed. The nests of some species are built entirely from threads of their saliva, and are collected for the famous Chinese delicacy
bird's nest soup
.
research, but the swiftlet tribe is a rather well-defined group. Its internal systematics
is confusing; the plumage is usually dull, with shades of black, brown, and gray; from their outward appearance, most species are very similar. Swiftlets have four toes, except the Papuan swiftlet
which lacks the hallux
(back toe). Their legs are very short, preventing the birds from perching, but allowing them to cling to vertical surfaces. Flight is mainly gliding due to very long primary feathers
and small breast muscles. The larger Aerodramus swiftlets weigh about 14 grams and are 10 cm long.
Swiftlets are insectivores; hymenoptera
ns and diptera
ns being the most abundant prey (Lourie & Tompkins, 2000). Typically, they leave the cave during the day to forage and return to their roost at night. Males and females look similar; as usual in such cases, these birds are monogamous and both partners take part in caring for the nestlings. Males perform aerial displays to attract females and mating occurs at the nest. The breeding season overlaps the wet season, which corresponds to an increased insect population. Clutch size depends on the location and the food source, but it is generally not large; Aerodramus swiftlets lay 1 to 2 eggs. The eggs are a dull white color and are laid every other day. Many if not all species are colonial
nesters; some build their nests in high, dark corners on cave walls. Swiftlets in temperate zones do migrate, but most Aerodramus swiftlets live in the tropical Indo-Pacific
region and do not migrate. These birds usually remain in one cave or other roosting/nesting site. Some examples of caves include the Niah Caves at Niah National Park & Gunung Mulu National Park
which are all located in Sarawak
, Malaysian Borneo
.
The genus Aerodramus is of special interest due to its use of echolocation
and its intricately constructed saliva
nests which in some species contain no other material such as feathers, moss or twigs and are collected, selling at extremely high prices (see Bird's nest soup
). It has been argued that the high demand for these nests could have had an adverse effect on their populations (Hobbs, 2003; Marcone, 2005) but other authorities (Jordan, 2004) have shown that modern techniques of nest farming have increased the bird population ( example refer to Hutanis Bird Nest ).
The use of echolocation was once used to separate Aerodramus from the non-echolocating genera Collocalia and Hydrochous (virtually nothing is known about Schoutedenapus). But recently, the Pygmy Swiftlet
Collocalia troglodytes was discovered making similar clicking noises in and outside its cave (Price et al., 2004). Characteristics of behavior, such as what materials other than saliva the nests contain, can be used to differentiate between certain species of Aerodramus (Lee et al., 1996).
s). The interpulse periods (IPPs) are varied depending on the level of light; in darker situations the bird emits shorter IPPs, as obstacles become harder to see, and longer IPPs are observed when the bird nears the exit of the cave. This behavior is similar to that of bats as they approach targets. The birds also emit a series of low clicks followed by a call when approaching the nests; presumably to warn nearby birds out of their way. It is thought that the double clicks are used to discriminate between individual birds. Aerodramus sawtelli, the Atiu Swiftlet
, and Aerodramus maximus, the Black-nest Swiftlet
are the only known species which emit single clicks. The single click is thought be used to avoid voice overlap during echolocation. The use of a single click might be associated with an evolutionary shift in eastern Pacific swiftlets; determining how many clicks the Marquesan Swiftlet
emits could shed light on this. It was also discovered that both the Atiu Swiftlet (Fullard, 1993) and the Papuan Swiftlet
(Price et al., 2005) emit clicks while foraging outside at dusk; the latter possibly only in these circumstances, considering that it might not nest in caves at all. Such behavior is not known to occur in other species (Fullard, 1993), but quite possibly does, given that the Papuan and Atiu Swiftlets are not closely related. However, it has recently been determined that the echolocation vocalizations do not agree with evolutionary relationship between swiftlet species as suggested by DNA
sequence comparison (Thomassen & Povel, 2006). This suggests that as in bat
s, echolocation sounds, once present, adapt rapidly and independently to the particular species' acoustic environment.
Three hypotheses are considered to describe how echolocation evolved in the genus Aerodramus and, as determined more recently, other taxa in the Apodidae. One hypothesis states that echolocation evolved from an ancestral species of swiftlets and was lost in the genera which lack echolocation. A second hypothesis is that echolocation evolved independently several times. The third scenario involves a combination of the first two, i.e. a gain-loss-regain scenario.
Several functional subunits (like vocal muscles and brain areals) are needed to produce the echolocating system. Past studies have thought that the loss of one of these subunits was more likely to occur than acquiring all the traits needed to echolocate. But a recent study (Thomassen et al., 2005) suggests that the echolocation subunits were mainly located in the central nervous system
, while the subunits in the vocal apparatus were already present and capable of use before echolocation even evolved. This study supports the second hypothesis of independent evolution of echolocation in Aerodramus and Collocalia, with the subsequent evolution of complex behavior needed to complement the physical echolocation system, or even the third approach, as the vocal apparatus-parts of the echolocation system might even be inherited from some prehistoric nocturnal ancestor.
(or White-nest) swiftlet (Aerodramus fuciphagus) and the Black-nest Swiftlet. Instead of twigs, feathers and straw, these swiftlets make their nest only from strands of their gummy saliva, which harden when exposed to air. Once the nests are harvested, they are cleaned and sold to restaurants. Eating swiftlet nest material is believed to help maintain skin tone, balance qi
("life energy") and reinforce the immune system
. It is also believed to strengthen the lungs and prevent coughs, improve the constitution and prolong life. The nutritional value of 100 g of dry nest includes 49.9 g of water-soluble protein (including amido nitrogen, monoamine nitrogen, non-amino nitrogen, arginine, humin, histidine, lysine and cysteine), 30.6 g carbohydrate (glycoprotein and mucin), 4.9 g iron, 2.5 g inorganic salt (including potassium, sodium, calcium, magnesium, sulfur, phosphorus, silica and other trace elements), and 1.4 g fiber (Dictionary of Traditional Chinese Medicine, The History of Chinese Medicine and the Nutrition Table).
The energy contained in 100 g of swiftlet nest is 345 kcal
. The nests are often served simmered in chicken
broth.
Authentic bird's-nest soup is quite popular throughout Asia. It is also extremely expensive; many western restaurants serve a less expensive version consisting of soup with noodles shaped to resemble a bird's nest.
from both the swiftlets and the many bats that inhabit the caves supports a huge array of specialized animals that feed on the dung. There are yet other creatures that have evolved to feed on these dung eaters as well as on the bats and the swiftlets themselves, including snake
s that can climb the sheer walls to snatch a passing meal and huge carnivorous crickets
that prey on chicks and bat pups. This cave fauna ecosystem
is self-sustaining, the only link with the outside being the birds and the bats that bring the nutrients into the caves in the first place.
The Philippine
municipality
of El Nido in Palawan
, known for its limestone
cliffs and pristine beaches, is home to a thriving bird's-nest market. The name El Nido is the Spanish
term for literally "The Nest". Many locals still practice manual climbing of the limestone caves to gather Swiftlet nests.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s contained within the four genera
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Aerodramus, Hydrochous, Schoutedenapus and Collocalia. They form the Collocaliini tribe
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
within the swift
Swift
The swifts are a family, Apodidae, of highly aerial birds. They are superficially similar to swallows, but are actually not closely related to passerine species at all; swifts are in the separate order Apodiformes, which they share with hummingbirds...
family Apodidae. The group contains around thirty species mostly confined to southern Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...
, south Pacific islands, and northeastern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, all within the tropical and subtropical regions. They are in many respects typical members of the Apodidae, having narrow wings for fast flight, with a wide gape and small reduced beak surrounded by bristles for catching insects in flight. What distinguishes many but not all species from other swifts and indeed almost all other birds is their ability to use a simple but effective form of echolocation
Animal echolocation
Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...
to navigate in total darkness through the chasms and shafts of the cave
Cave
A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...
s where they roost at night and breed. The nests of some species are built entirely from threads of their saliva, and are collected for the famous Chinese delicacy
Chinese cuisine
Chinese cuisine is any of several styles originating in the regions of China, some of which have become highly popular in other parts of the world – from Asia to the Americas, Australia, Western Europe and Southern Africa...
bird's nest soup
Bird's nest soup
Bird's nest soup is a delicacy in Chinese cuisine. A few species of swift, the cave swifts, are renowned for building the saliva nests used to produce the unique texture of this soup....
.
Description and ecology
The swift family remains one of the more complicated groups of birds in taxonomicTaxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
research, but the swiftlet tribe is a rather well-defined group. Its internal systematics
Systematics
Biological systematics is the study of the diversification of terrestrial life, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees...
is confusing; the plumage is usually dull, with shades of black, brown, and gray; from their outward appearance, most species are very similar. Swiftlets have four toes, except the Papuan swiftlet
Papuan Swiftlet
The Three-toed Swiftlet or Papuan Swiftlet is a species of swift.It is found in Indonesia and Papua New Guinea.-Source:* BirdLife International 2004. . Downloaded on 24 July 2007....
which lacks the hallux
Hallux
In tetrapods, the hallux is the innermost toe of the foot. Despite its name it may not be the longest toe on the foot of some individuals...
(back toe). Their legs are very short, preventing the birds from perching, but allowing them to cling to vertical surfaces. Flight is mainly gliding due to very long primary feathers
Flight feather
Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices . Their primary function is to aid in the generation of both thrust and lift, thereby...
and small breast muscles. The larger Aerodramus swiftlets weigh about 14 grams and are 10 cm long.
Swiftlets are insectivores; hymenoptera
Hymenoptera
Hymenoptera is one of the largest orders of insects, comprising the sawflies, wasps, bees and ants. There are over 130,000 recognized species, with many more remaining to be described. The name refers to the heavy wings of the insects, and is derived from the Ancient Greek ὑμήν : membrane and...
ns and diptera
Diptera
Diptera , or true flies, is the order of insects possessing only a single pair of wings on the mesothorax; the metathorax bears a pair of drumstick like structures called the halteres, the remnants of the hind wings. It is a large order, containing an estimated 240,000 species, although under half...
ns being the most abundant prey (Lourie & Tompkins, 2000). Typically, they leave the cave during the day to forage and return to their roost at night. Males and females look similar; as usual in such cases, these birds are monogamous and both partners take part in caring for the nestlings. Males perform aerial displays to attract females and mating occurs at the nest. The breeding season overlaps the wet season, which corresponds to an increased insect population. Clutch size depends on the location and the food source, but it is generally not large; Aerodramus swiftlets lay 1 to 2 eggs. The eggs are a dull white color and are laid every other day. Many if not all species are colonial
Bird colony
A bird colony is a large congregation of individuals of one or more species of bird that nest or roost in close proximity at a particular location. Many kinds of birds are known to congregate in groups of varying size; a congregation of nesting birds is called a breeding colony...
nesters; some build their nests in high, dark corners on cave walls. Swiftlets in temperate zones do migrate, but most Aerodramus swiftlets live in the tropical Indo-Pacific
Indo-Pacific
The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...
region and do not migrate. These birds usually remain in one cave or other roosting/nesting site. Some examples of caves include the Niah Caves at Niah National Park & Gunung Mulu National Park
Gunung Mulu National Park
Gunung Mulu National Park near Miri, Sarawak, Malaysian Borneo, is a UNESCO World Heritage Site that encompasses incredible caves and karst formations in a mountainous equatorial rainforest setting...
which are all located in Sarawak
Sarawak
Sarawak is one of two Malaysian states on the island of Borneo. Known as Bumi Kenyalang , Sarawak is situated on the north-west of the island. It is the largest state in Malaysia followed by Sabah, the second largest state located to the North- East.The administrative capital is Kuching, which...
, Malaysian Borneo
Borneo
Borneo is the third largest island in the world and is located north of Java Island, Indonesia, at the geographic centre of Maritime Southeast Asia....
.
The genus Aerodramus is of special interest due to its use of echolocation
Animal echolocation
Echolocation, also called biosonar, is the biological sonar used by several kinds of animals.Echolocating animals emit calls out to the environment and listen to the echoes of those calls that return from various objects near them. They use these echoes to locate and identify the objects...
and its intricately constructed saliva
Saliva
Saliva , referred to in various contexts as spit, spittle, drivel, drool, or slobber, is the watery substance produced in the mouths of humans and most other animals. Saliva is a component of oral fluid. In mammals, saliva is produced in and secreted from the three pairs of major salivary glands,...
nests which in some species contain no other material such as feathers, moss or twigs and are collected, selling at extremely high prices (see Bird's nest soup
Bird's nest soup
Bird's nest soup is a delicacy in Chinese cuisine. A few species of swift, the cave swifts, are renowned for building the saliva nests used to produce the unique texture of this soup....
). It has been argued that the high demand for these nests could have had an adverse effect on their populations (Hobbs, 2003; Marcone, 2005) but other authorities (Jordan, 2004) have shown that modern techniques of nest farming have increased the bird population ( example refer to Hutanis Bird Nest ).
The use of echolocation was once used to separate Aerodramus from the non-echolocating genera Collocalia and Hydrochous (virtually nothing is known about Schoutedenapus). But recently, the Pygmy Swiftlet
Pygmy Swiftlet
The Pygmy Swiftlet is a species of swift in the Apodidae family.It is endemic to the Philippines.Its natural habitat is subtropical or tropical moist lowland forests. At under 9 cm , it the world's smallest swift....
Collocalia troglodytes was discovered making similar clicking noises in and outside its cave (Price et al., 2004). Characteristics of behavior, such as what materials other than saliva the nests contain, can be used to differentiate between certain species of Aerodramus (Lee et al., 1996).
Echolocation
The genus Aerodramus was thought to be the only echolocating swiftlets. These birds use echolocation to locate their roost in dark caves. Unlike a bat’s echolocation, Aerodramus swiftlets make clicking noises that are well within the human range of hearing. The clicks consist of two broad band pulses (3 - 10 kHz) separated by a slight pause (1 - 3 millisecondMillisecond
A millisecond is a thousandth of a second.10 milliseconds are called a centisecond....
s). The interpulse periods (IPPs) are varied depending on the level of light; in darker situations the bird emits shorter IPPs, as obstacles become harder to see, and longer IPPs are observed when the bird nears the exit of the cave. This behavior is similar to that of bats as they approach targets. The birds also emit a series of low clicks followed by a call when approaching the nests; presumably to warn nearby birds out of their way. It is thought that the double clicks are used to discriminate between individual birds. Aerodramus sawtelli, the Atiu Swiftlet
Atiu Swiftlet
The Atiu Swiftlet is a species of bird in the swift family and endemic to Atiu in the Cook Islands.Its natural habitats are the islands fernlands and mixed horticultural areas over which it feeds and in makatea limestone caves within which it nests.-External links:*...
, and Aerodramus maximus, the Black-nest Swiftlet
Black-nest Swiftlet
The Black-nest Swiftlet is a species of swift in the Apodidae family.It is found in Brunei, Indonesia, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam....
are the only known species which emit single clicks. The single click is thought be used to avoid voice overlap during echolocation. The use of a single click might be associated with an evolutionary shift in eastern Pacific swiftlets; determining how many clicks the Marquesan Swiftlet
Marquesan Swiftlet
The Marquesan Swiftlet is a species of swift in the Apodidae family. It is endemic to French Polynesia. Its natural habitat is subtropical or tropical moist lowland forests.-References:...
emits could shed light on this. It was also discovered that both the Atiu Swiftlet (Fullard, 1993) and the Papuan Swiftlet
Papuan Swiftlet
The Three-toed Swiftlet or Papuan Swiftlet is a species of swift.It is found in Indonesia and Papua New Guinea.-Source:* BirdLife International 2004. . Downloaded on 24 July 2007....
(Price et al., 2005) emit clicks while foraging outside at dusk; the latter possibly only in these circumstances, considering that it might not nest in caves at all. Such behavior is not known to occur in other species (Fullard, 1993), but quite possibly does, given that the Papuan and Atiu Swiftlets are not closely related. However, it has recently been determined that the echolocation vocalizations do not agree with evolutionary relationship between swiftlet species as suggested by DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
sequence comparison (Thomassen & Povel, 2006). This suggests that as in bat
Bat
Bats are mammals of the order Chiroptera "hand" and pteron "wing") whose forelimbs form webbed wings, making them the only mammals naturally capable of true and sustained flight. By contrast, other mammals said to fly, such as flying squirrels, gliding possums, and colugos, glide rather than fly,...
s, echolocation sounds, once present, adapt rapidly and independently to the particular species' acoustic environment.
Three hypotheses are considered to describe how echolocation evolved in the genus Aerodramus and, as determined more recently, other taxa in the Apodidae. One hypothesis states that echolocation evolved from an ancestral species of swiftlets and was lost in the genera which lack echolocation. A second hypothesis is that echolocation evolved independently several times. The third scenario involves a combination of the first two, i.e. a gain-loss-regain scenario.
Several functional subunits (like vocal muscles and brain areals) are needed to produce the echolocating system. Past studies have thought that the loss of one of these subunits was more likely to occur than acquiring all the traits needed to echolocate. But a recent study (Thomassen et al., 2005) suggests that the echolocation subunits were mainly located in the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
, while the subunits in the vocal apparatus were already present and capable of use before echolocation even evolved. This study supports the second hypothesis of independent evolution of echolocation in Aerodramus and Collocalia, with the subsequent evolution of complex behavior needed to complement the physical echolocation system, or even the third approach, as the vocal apparatus-parts of the echolocation system might even be inherited from some prehistoric nocturnal ancestor.
Culinary use
Authentic bird's-nest soup is made from nests of some species of swiftlet, mainly the Edible-nestEdible-nest Swiftlet
The Edible-nest Swiftlet is a small bird of the swift family which is found in South-east Asia. Its nest is made of solidified saliva and is used to make bird's nest soup.-Description:...
(or White-nest) swiftlet (Aerodramus fuciphagus) and the Black-nest Swiftlet. Instead of twigs, feathers and straw, these swiftlets make their nest only from strands of their gummy saliva, which harden when exposed to air. Once the nests are harvested, they are cleaned and sold to restaurants. Eating swiftlet nest material is believed to help maintain skin tone, balance qi
Qi
In traditional Chinese culture, qì is an active principle forming part of any living thing. Qi is frequently translated as life energy, lifeforce, or energy flow. Qi is the central underlying principle in traditional Chinese medicine and martial arts...
("life energy") and reinforce the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
. It is also believed to strengthen the lungs and prevent coughs, improve the constitution and prolong life. The nutritional value of 100 g of dry nest includes 49.9 g of water-soluble protein (including amido nitrogen, monoamine nitrogen, non-amino nitrogen, arginine, humin, histidine, lysine and cysteine), 30.6 g carbohydrate (glycoprotein and mucin), 4.9 g iron, 2.5 g inorganic salt (including potassium, sodium, calcium, magnesium, sulfur, phosphorus, silica and other trace elements), and 1.4 g fiber (Dictionary of Traditional Chinese Medicine, The History of Chinese Medicine and the Nutrition Table).
The energy contained in 100 g of swiftlet nest is 345 kcal
Calorie
The calorie is a pre-SI metric unit of energy. It was first defined by Nicolas Clément in 1824 as a unit of heat, entering French and English dictionaries between 1841 and 1867. In most fields its use is archaic, having been replaced by the SI unit of energy, the joule...
. The nests are often served simmered in chicken
Chicken
The chicken is a domesticated fowl, a subspecies of the Red Junglefowl. As one of the most common and widespread domestic animals, and with a population of more than 24 billion in 2003, there are more chickens in the world than any other species of bird...
broth.
Authentic bird's-nest soup is quite popular throughout Asia. It is also extremely expensive; many western restaurants serve a less expensive version consisting of soup with noodles shaped to resemble a bird's nest.
Cave ecology
GuanoGuano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...
from both the swiftlets and the many bats that inhabit the caves supports a huge array of specialized animals that feed on the dung. There are yet other creatures that have evolved to feed on these dung eaters as well as on the bats and the swiftlets themselves, including snake
Snake
Snakes are elongate, legless, carnivorous reptiles of the suborder Serpentes that can be distinguished from legless lizards by their lack of eyelids and external ears. Like all squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales...
s that can climb the sheer walls to snatch a passing meal and huge carnivorous crickets
Cricket (insect)
Crickets, family Gryllidae , are insects somewhat related to grasshoppers, and more closely related to katydids or bush crickets . They have somewhat flattened bodies and long antennae. There are about 900 species of crickets...
that prey on chicks and bat pups. This cave fauna ecosystem
Ecosystem
An ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
is self-sustaining, the only link with the outside being the birds and the bats that bring the nutrients into the caves in the first place.
The Philippine
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
municipality
Municipality
A municipality is essentially an urban administrative division having corporate status and usually powers of self-government. It can also be used to mean the governing body of a municipality. A municipality is a general-purpose administrative subdivision, as opposed to a special-purpose district...
of El Nido in Palawan
Palawan
Palawan is an island province of the Philippines located in the MIMAROPA region or Region 4. Its capital is Puerto Princesa City, and it is the largest province in the country in terms of total area of jurisdiction. The islands of Palawan stretch from Mindoro in the northeast to Borneo in the...
, known for its limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
cliffs and pristine beaches, is home to a thriving bird's-nest market. The name El Nido is the Spanish
Spanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
term for literally "The Nest". Many locals still practice manual climbing of the limestone caves to gather Swiftlet nests.
Species
The Papuan Swiftlet is apparently closer to the Waterfall Swift than to the other Aerodramus species and probably best placed in a separate genus (Price et al., 2005), whereas Thomassen et al. (2005) advocate reuniting all swiftlets in Collocalia. Schoutedenapus is one of the least-known genera of birds.- Genus CollocaliaCollocaliaCollocalia is a genus of swifts, containing some of the smaller species termed "swiftlets". Formerly a catch-all genus for these, a number of its erstwhile members are now normally placed in Aerodramus....
- Glossy SwiftletGlossy SwiftletThe Glossy Swiftlet is a species of swift in the Apodidae family.It is found in Australia, Brunei, Christmas Island, India, Indonesia, Malaysia, Myanmar, New Caledonia, Papua New Guinea, the Philippines, Singapore, Solomon Islands, Thailand, and Vanuatu.It is shiny black-blue above, including its...
, Collocalia esculenta- Grey-rumped Swiftlet, Collocalia (esculenta) marginata
- Cave SwiftletCave SwiftletThe Cave Swiftlet is a species of swift in the Apodidae family.It is found in Indonesia and Malaysia.-References:* BirdLife International 2004. . Downloaded on 24 July 2007....
, Collocalia linchi - Pygmy SwiftletPygmy SwiftletThe Pygmy Swiftlet is a species of swift in the Apodidae family.It is endemic to the Philippines.Its natural habitat is subtropical or tropical moist lowland forests. At under 9 cm , it the world's smallest swift....
, Collocalia troglodytes
- Glossy Swiftlet
- Genus AerodramusAerodramusAerodramus is a genus of small, dark, cave-nesting birds in the Collocaliini tribe of the swift family. Its members are confined to tropical and subtropical regions in southern Asia, Oceania and northeastern Australia...
- Seychelles SwiftletSeychelles SwiftletThe Seychelles Swiftlet is a small bird of the swift family. It is found only in the Seychelles Islands in the Indian Ocean....
, Aerodramus elaphrus - Mascarene SwiftletMascarene SwiftletThe Mascarene Swiftlet is a species of swift in the Apodidae family.It is found in Mauritius and Réunion.Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical high-altitude shrubland, subtropical or tropical high-altitude grassland, caves, arable land, and...
, Aerodramus francicus - Indian SwiftletIndian SwiftletThe Indian Swiftlet, or Indian Edible-nest Swiftlet, Aerodramus unicolor, is a small swift. It is a common resident colonial breeder in the hills of Sri Lanka and south west India.The half-cup nest is built on a vertical surface, often in a cave...
, Aerodramus unicolor - Philippine SwiftletPhilippine SwiftletThe Philippine Swiftlet is a species of swift in the Apodidae family. It is endemic to the Philippines.Its natural habitats are subtropical or tropical dry forests, subtropical or tropical moist lowland forests, and subtropical or tropical moist montane forests.-References:* BirdLife International...
, Aerodramus mearnsi - Moluccan SwiftletMoluccan SwiftletThe Moluccan Swiftlet is a species of swift in the Apodidae family.It is endemic to Indonesia.Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montanes.-References:...
, Aerodramus infuscatus - Mountain SwiftletMountain SwiftletThe Mountain Swiftlet is a species of swift in the family Apodidae. It is endemic to the island of New Guinea and the nearby islands of Karkar, Yapen and Goodenough. It was once placed in the genus Collocalia but has been moved, with many others, to Aerodramus. The species is divided into three...
, Aerodramus hirundinaceus - White-rumped SwiftletWhite-rumped SwiftletThe White-rumped Swiftlet is a species of swift in the Apodidae family.It is found in American Samoa, Fiji, New Caledonia, Papua New Guinea, Samoa, Solomon Islands, Tonga, and Vanuatu...
, Aerodramus spodiopygius - Australian SwiftletAustralian SwiftletThe Australian Swiftlet is a small bird belonging to the genus Aerodramus in the swift family, Apodidae. It is endemic to Queensland in north-eastern Australia. It was formerly included in the White-rumped Swiftlet but is now commonly treated as a separate species...
, Aerodramus terraereginae - Himalayan SwiftletHimalayan SwiftletThe Himalayan Swiftlet, Aerodramus brevirostris, is a small swift. It is a common colonial breeder in the Himalayas and Southeast Asia. Some populations are migratory....
, Aerodramus brevirostris - Indochinese Swiftlet, Aerodramus rogersi
- Volcano Swiftlet, Aerodramus vulcanorum
- Whitehead's SwiftletWhitehead's SwiftletThe Whitehead's Swiftlet is a species of swift in the Apodidae family. It is endemic to the Philippines.Its natural habitat is subtropical or tropical moist montane forests. Its status is insufficiently known.-Source:...
, Aerodramus whiteheadi - Bare-legged SwiftletBare-legged SwiftletThe Bare-legged Swiftlet is a species of swift in the Apodidae family.It is found in Indonesia and Papua New Guinea.-References:* BirdLife International 2004. . Downloaded on 24 July 2007....
, Aerodramus nuditarsus - Mayr's SwiftletMayr's SwiftletThe Mayr's Swiftlet is a species of swift in the Apodidae family.It is found in Papua New Guinea and Solomon Islands.-Source:* BirdLife International 2004. . Downloaded on 24 July 2007....
, Aerodramus orientalis - Palawan SwiftletPalawan SwiftletThe Palawan Swiftlet is a species of swift in the Apodidae family. Some taxonomists consider it to be a subspecies of the Uniform Swiftlet. It is endemic to the Philippines....
, Aerodramus palawanensis - Mossy-nest SwiftletMossy-nest SwiftletThe Mossy-nest Swiftlet is a species of swift in the Apodidae family. Some taxonomists consider it to be a subspecies of the Uniform Swiftlet. It is found in northern Borneo, the Natuna and the Derawan Islands, islands off western Sumatra and Java...
, Aerodramus salangana - Uniform SwiftletUniform SwiftletThe Uniform Swiftlet, , also known as the Vanikoro or Lowland Swiftlet, is a gregarious, medium-sized swiftlet with a shallowly forked tail. The colouring is dark grey-brown, darker on the upperparts with somewhat paler underparts, especially on chin and throat...
, Aerodramus vanikorensis - Palau SwiftletPalau SwiftletThe Palau Swiftlet is a species of swift in the Apodidae family.It is endemic to Palau.Its natural habitat is subtropical or tropical moist lowland forests.-References:...
, Aerodramus pelewensis - Guam SwiftletGuam SwiftletThe Mariana Swiftlet or Guam Swiftlet, is a species of swift in the Apodidae family.It is found in Guam, Northern Mariana Islands, and the United States....
, Aerodramus bartschi - Caroline Islands Swiftlet, Aerodramus inquietus
- Mangaia SwiftletMangaia SwiftletThe Mangaia Swiftlet is an extinct species of bird in the swift family. It became extinct during prehistoric times. It was endemic to Mangaia, Cook Islands...
, Aerodramus manuoi (prehistoricLate Quaternary prehistoric birdsPrehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists...
) - Atiu SwiftletAtiu SwiftletThe Atiu Swiftlet is a species of bird in the swift family and endemic to Atiu in the Cook Islands.Its natural habitats are the islands fernlands and mixed horticultural areas over which it feeds and in makatea limestone caves within which it nests.-External links:*...
, Aerodramus sawtelli - Polynesian Swiftlet, Aerodramus leucophaeus
- Marquesan SwiftletMarquesan SwiftletThe Marquesan Swiftlet is a species of swift in the Apodidae family. It is endemic to French Polynesia. Its natural habitat is subtropical or tropical moist lowland forests.-References:...
, Aerodramus ocistus - Black-nest SwiftletBlack-nest SwiftletThe Black-nest Swiftlet is a species of swift in the Apodidae family.It is found in Brunei, Indonesia, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam....
, Aerodramus maximus - Edible-nest SwiftletEdible-nest SwiftletThe Edible-nest Swiftlet is a small bird of the swift family which is found in South-east Asia. Its nest is made of solidified saliva and is used to make bird's nest soup.-Description:...
, Aerodramus fuciphagus- Brown-rumped Swiftlet, Aerodramus (fuciphagus) vestitus
- German's SwiftletGerman's SwiftletThe German's Swiftlet is a species of swift.It is found in China, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam. Its natural habitats are subtropical or tropical moist lowland forests and subtropical or tropical moist montanes.-Description:This swiftlet is...
, Aerodramus germani - Papuan SwiftletPapuan SwiftletThe Three-toed Swiftlet or Papuan Swiftlet is a species of swift.It is found in Indonesia and Papua New Guinea.-Source:* BirdLife International 2004. . Downloaded on 24 July 2007....
, Aerodramus papuensis - probably a distinct genus
- Seychelles Swiftlet
- Genus Hydrochous
- Waterfall SwiftWaterfall SwiftThe Waterfall Swift , also known as the Giant Swiftlet, is a species of swift in the Apodidae family. It is monotypic within the genus Hydrochous. It is found in Indonesia and Malaysia. Its natural habitats are subtropical or tropical moist montanes and rivers. It is threatened by habitat loss....
, Hydrochous gigas
- Waterfall Swift
- Genus SchoutedenapusSchoutedenapusSchoutedenapus is a genus of swift in the Apodidae family.It contains the following species:* Scarce Swift * Schouteden's Swift...
- Scarce SwiftScarce SwiftThe Scarce Swift is a species of swift in the Apodidae family.It is found in Angola, Burundi, Cameroon, Democratic Republic of the Congo, Equatorial Guinea, Ethiopia, Kenya, Malawi, Mozambique, Rwanda, Sudan, Tanzania, Uganda, Zambia, and Zimbabwe.-References:* BirdLife International 2004. . ...
, Schoutedenapus myoptilus - Schouteden's SwiftSchouteden's SwiftThe Schouteden's Swift is a species of swift in the Apodidae family.It is endemic to Democratic Republic of the Congo....
, Schoutedenapus schoutedeni
- Scarce Swift