Bold text The birds called Swiftlets or Cave Swiftlets are 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 ^[1] is their ability to use a simple but effective form of echolocation to navigate in total darkness through the chasms and shafts of the caves where they roost at night and breed. The nests of some species are collected for the famous Chinese delicacy Bird's nest soup. For other uses, see Scientific classification (disambiguation). ... For other uses, see Animal (disambiguation). ... Typical Classes See below Chordates (phylum Chordata) are a group of animals that includes the vertebrates, together with several closely related invertebrates. ... For other meanings of bird, see bird (disambiguation). ... Families Apodidae Hemiprocnidae Traditionally, the bird order Apodiformes contained three families: the swifts, Apodidae, the tree swifts, Hemiprocnidae, and the hummingbirds, Trochilidae. ... For other meanings of the word Swift see Swift (disambiguation). ... Binomial name (Hartert & Butler, 1901) Synonyms Hydrochrous gigas (Hartert & Butler, 1901) [orthographic error] The Waterfall Swift (Hydrochous gigas) is a species of swift in the Apodidae family. ... Collocalia is a genus of swift in the Apodidae family. ... Genera Hydrochous Collocalia Aerodramus Schoutedenapus The birds called Swiftlets or Cave Swiftlets are contained within the four genera of Aerodramus, Hydrochous, Schoutedenapus and the remaining species left in Collocalia. ... Schoutedenapus is a genus of swift in the Apodidae family. ... For other uses, see Bird (disambiguation). ... For other uses, see Genus (disambiguation). ... In biology, a tribe is a taxonomic classification in between family and genus. ... For other uses, see Swift (disambiguation). ... For other meanings of the word Swift see Swift (disambiguation). ... For other uses, see Asia (disambiguation). ... For other meanings of Pacific, see Pacific (disambiguation). ... The tropics are the geographic region of the Earth centered on the equator and limited in latitude by the two tropics: the Tropic of Cancer in the north and the Tropic of Capricorn in the southern hemisphere. ... Subtropical (or semitropical) areas are those adjacent to the tropics, usually roughly defined as the ranges 23. ... See: Animal echolocation: animals emitting sound waves and listening to the echo in order to locate objects or navigate. ... For other uses, see Cave (disambiguation). ... Chinese cuisine (Chinese: 中國菜) is widely seen as representing one of the richest and most diverse culinary cuisines and heritages in the world. ... The key ingredient of bird-nest soup Bird Nests box showing $888. ...

Description and ecology

The swift family remains one of the more complicated groups of birds in taxonomic 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. Look up taxonomy in Wiktionary, the free dictionary. ... Biological systematics is the study of the diversity of life on the planet earth, both past and present, and the relationships among living things through time. ... Toes on foot. ... Red Kite (Milvus milvus) in flight, showing remiges and rectrices. ...

Swiftlets are insectivores; hymenopterans and dipterans 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 1-2 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. Suborders Apocrita Symphyta Hymenoptera is one of the larger orders of insects, comprising the sawflies, wasps, bees, and ants. ... Suborders Nematocera (includes Eudiptera) Brachycera Diptera (di - two, ptera - wings), 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. ... The Indo-Pacific is the aggregate of the Indian Ocean, Pacific Ocean, and the minor seas between the two in the general area of Indonesia. ... The opening of the Deer Cave, seen from the inside. ... State motto: Bersatu, Berusaha, Berbakti State anthem: Ibu Pertiwiku Capital Kuching Ruling party Barisan Nasional  - Yang di-Pertua Negeri Abang Muhammad Salahuddin  - Ketua Menteri Abdul Taib Mahmud History    - Brunei Sultanate 19th century   - Brooke dynasty 1841   - Japanese occupation 1941-1945   - British control 1946   - Accession into Malaysia 1963  Area  - Total 124,450... It has been suggested that this article or section be merged with Kalimantan. ...

The genus Aerodramus is of special interest due to its use of echolocation and their 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). Over the past twenty years, the high demand for the nests of some Aerodramus species has had an adverse effect on their populations (Hobbs, 2003; Marcone, 2005). Echolocation, also called Biosonar, is the biological sonar used by several mammals such as bats (although not all species), dolphins and whales (though not baleen whales). ... Saliva is the watery and usually frothy substance produced in the mouths of humans and some animals. ... The key ingredient of bird-nest soup Bird Nests box showing $888. ...

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 their cave (Price et al., 2004). Characteristics of behavior, such as what materials apart from saliva the nests contain, can be used to differentiate between certain species of Aerodramus (Lee et al., 1996). Binomial name Gray, 1845 The Pygmy Swiftlet (Collocalia troglodytes) is a species of swift in the Apodidae family. ...

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 milliseconds). 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 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 it might not nest in caves at all. Such behavior is not known to occur in other species (Fullard, 1993) but quite possibly goes 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 bats, echolocation sounds, once present, adapt rapidly and independently to the particular species' acoustic environment. A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... One millisecond is one-thousandth of a second. ... Binomial name Holyoak, 1974 The Atiu Swiftlet (Collocalia sawtelli) is a species of swift in the Apodidae family. ... Binomial name Hume, 1878 The Black-nest Swiftlet (Collocalia maxima) is a species of swift in the Apodidae family. ... Binomial name (Oberholser, 1906) The Marquesan Swiftlet (Collocalia ocista) is a species of swift in the Apodidae family. ... Binomial name Rand, 1941 The Papuan Swiftlet (Collocalia papuensis) is a species of swift in the Apodidae family. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... “Chiroptera” redirects here. ...

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. A diagram showing the CNS: 1. ... Prehistory (Greek words προ = before and ιστορία = history) is the period of human history prior to the advent of writing (which marks the beginning of recorded history). ... A nocturnal animal is one that sleeps during the day and is active at night - the opposite of the human (diurnal) schedule. ...

Culinary use

Main article: Bird's nest soup

Authentic bird's nest soup is made from nests of some species of swiftlet, mainly the Edible-nest (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 thought to strengthen the lungs and prevent coughs, improve the constitution and prolong life. Research shows that every 100 g of dry nest contains 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 key ingredient of bird-nest soup Bird Nests box showing $888. ... Genera Hydrochous Collocalia Aerodramus Schoutedenapus The birds called Swiftlets or Cave Swiftlets are contained within the four genera of Aerodramus, Hydrochous, Schoutedenapus and the remaining species left in Collocalia. ... For other uses, see Qi (disambiguation). ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ...

The energy contained in 100 g of swiftlet nest is 345 kcal. The nests are often served simmered in chicken broth. A calorie is a unit of measurement for energy. ... This article or section does not adequately cite its references or sources. ...

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

Guano 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 snakes 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 Chincha guano islands in Peru. ... For other uses, see Snake (disambiguation). ... Subfamilies See Taxonomy section Crickets, family Gryllidae (also known as true crickets), are insects somewhat related to grasshoppers and more closely related to katydids or bush crickets (family Tettigoniidae). ... A coral reef near the Hawaiian islands is an example of a complex marine ecosystem. ...

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. A municipality is an administrative entity composed of a clearly defined territory and its population and commonly referring to a city, town, or village, or a small grouping of them. ... Categories: Philippines geography stubs | Municipalities in the Philippines ... Palawan is an island province of the Philippines located in the Mimaropa region. ... For other uses, see Limestone (disambiguation). ... geography, a cliff is a significant vertical, or near vertical, rock exposure. ... Beaches is a 1988 movie adapted by Mary Agnes Donoghue from the novel Beaches by Iris Rainer Dart. ... Categories: Philippines geography stubs | Municipalities in the Philippines ...

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 Collocalia
  • Glossy Swiftlet, Collocalia esculenta
    • Grey-rumped Swiftlet, Collocalia (esculenta) marginata
  • Cave Swiftlet, Collocalia linchi
  • Pygmy Swiftlet, Collocalia troglodytes

• Genus Aerodramus
  • Seychelles Swiftlet, Aerodramus elaphrus
  • Mascarene Swiftlet, Aerodramus francicus
  • Indian Swiftlet, Aerodramus unicolor
  • Philippine Swiftlet, Aerodramus mearnsi
  • Moluccan Swiftlet, Aerodramus infuscatus
  • Mountain Swiftlet, Aerodramus hirundinaceus
  • White-rumped Swiftlet, Aerodramus spodiopygius
  • Australian Swiftlet, Aerodramus terraereginae
  • Himalayan Swiftlet, Aerodramus brevirostris
  • Indochinese Swiftlet, Aerodramus rogersi
  • Volcano Swiftlet, Aerodramus vulcanorum
  • Whitehead's Swiftlet, Aerodramus whiteheadi
  • Bare-legged Swiftlet, Aerodramus nuditarsus
  • Mayr's Swiftlet, Aerodramus orientalis
  • Palawan Swiftlet, Aerodramus palawanensis
  • Mossy-nest Swiftlet, Aerodramus salangana
  • Uniform Swiftlet, Aerodramus vanikorensis
  • Palau Swiftlet, Aerodramus pelewensis
  • Guam Swiftlet, Aerodramus bartschi
  • Caroline Islands Swiftlet, Aerodramus inquietus
  • Mangaia Swiftlet, Aerodramus manuoi (prehistoric)
  • Atiu Swiftlet, Aerodramus sawtelli
  • Polynesian Swiftlet, Aerodramus leucophaeus
  • Marquesan Swiftlet, Aerodramus ocistus
  • Black-nest Swiftlet, Aerodramus maximus
  • Edible-nest Swiftlet, Aerodramus fuciphagus
    • Brown-rumped Swiftlet, Aerodramus (fuciphagus) vestitus
  • German's Swiftlet, Aerodramus germani
  • Papuan Swiftlet, Aerodramus papuensis - probably a distinct genus

• Genus Hydrochous
  • Waterfall Swift, Hydrochous gigas

• Genus Schoutedenapus
  • Scarce Swift, Schoutedenapus myoptilus
  • Schouteden's Swift, Schoutedenapus schoutedeni

Collocalia is a genus of swift in the Apodidae family. ... Binomial name (Linnaeus, 1758) The Glossy Swiftlet (Collocalia esculenta) is a species of swift in the Apodidae family. ... Genera Hydrochous Collocalia Aerodramus Schoutedenapus The birds called Swiftlets or Cave Swiftlets are contained within the four genera Aerodramus, Hydrochous, Schoutedenapus and Collocalia. ... Binomial name Gray, 1845 The Pygmy Swiftlet (Collocalia troglodytes) is a species of swift in the Apodidae family. ... Genera Hydrochous Collocalia Aerodramus Schoutedenapus The birds called Swiftlets or Cave Swiftlets are contained within the four genera of Aerodramus, Hydrochous, Schoutedenapus and the remaining species left in Collocalia. ... Binomial name (Oberholser, 1906) Synonyms Collocalia elaphra The Seychelles Swiftlet (Aerodramus elaphrus) is a small bird of the swift family. ... Binomial name (Gmelin, 1789) The Mascarene Swiftlet (Collocalia francica) is a species of swift in the Apodidae family. ... Binomial name Aerodramus unicolor (Jerdon, 1840) The Indian Swiftlet, or Indian Edible-nest Swiftlet, Aerodramus unicolor, is a small swift. ... Binomial name Oberholser, 1912 The Philippine Swiftlet (Collocalia mearnsi) is a species of swift in the Apodidae family. ... Binomial name Salvadori, 1880 The Moluccan Swiftlet (Collocalia infuscata) is a species of swift in the Apodidae family. ... Binomial name Stresemann, 1914 The Mountain Swiftlet (Collocalia hirundinacea) is a species of swift in the Apodidae family. ... Binomial name (Peale, 1848) Synonyms Collocalia spodiopygia (Peale, 1848) [orthographic error] Collocalia spodiopygius (Peale, 1848) [orthorgraphic error] Collocalia terraereginae (Ramsay, 1875) The White-rumped Swiftlet (Collocalia spodiopygia) is a species of swift in the Apodidae family. ... Binomial name (Ramsay, 1875) Synonyms Collocalia terraereginae The Australian Swiftlet (Aerodramus terraereginae) is a small bird belonging to the genus Aerodramus in the swift family, Apodidae. ... Binomial name (Horsfield, 1840) The Himalayan Swiftlet, Collocalia brevirostris, is a small swift. ... Binomial name (Horsfield, 1840) The Himalayan Swiftlet, Collocalia brevirostris, is a small swift. ... Binomial name (Horsfield, 1840) The Himalayan Swiftlet, Collocalia brevirostris, is a small swift. ... Binomial name (Ogilvie-Grant, 1895) The Whiteheads Swiftlet (Collocalia whiteheadi) is a species of swift in the Apodidae family. ... Binomial name (Salomonsen, 1962) The Bare-legged Swiftlet (Collocalia nuditarsus) is a species of swift in the Apodidae family. ... Binomial name (Mayr, 1935) The Mayrs Swiftlet (Collocalia orientalis) is a species of swift in the Apodidae family. ... Binomial name Stresemann, 1914 The Palawan Swiftlet (Collocalia palawanensis) is a species of swift in the Apodidae family. ... Binomial name (Quoy & Gaimard, 1830) The Uniform Swiftlet ( Collocalia vanikorensis ), also known as the Vanikoro or Lowland Swiftlet, is a gregarious, medium-sized (27 cm wingspan, 13 cm in length, 11 g in weight), swiftlet with a shallowly forked tail. ... Binomial name (Quoy & Gaimard, 1830) The Uniform Swiftlet ( Collocalia vanikorensis ), also known as the Vanikoro or Lowland Swiftlet, is a gregarious, medium-sized (27 cm wingspan, 13 cm in length, 11 g in weight), swiftlet with a shallowly forked tail. ... Binomial name Mayr, 1935 The Palau Swiftlet (Collocalia pelewensis) is a species of swift in the Apodidae family. ... Binomial name Mearns, 1909 The Guam Swiftlet (Collocalia bartschi) is a species of swift in the Apodidae family. ... Binomial name (Quoy & Gaimard, 1830) The Uniform Swiftlet ( Collocalia vanikorensis ), also known as the Vanikoro or Lowland Swiftlet, is a gregarious, medium-sized (27 cm wingspan, 13 cm in length, 11 g in weight), swiftlet with a shallowly forked tail. ... Prehistoric birds are various taxa of birds that became extinct before recorded history, or more precisely, before they could be studied alive by bird scientists. ... Binomial name Holyoak, 1974 The Atiu Swiftlet (Collocalia sawtelli) is a species of swift in the Apodidae family. ... Binomial name (Peale, 1848) Synonyms Collocalia leucophaeus (Peale, 1848) [orth. ... Binomial name (Oberholser, 1906) The Marquesan Swiftlet (Collocalia ocista) is a species of swift in the Apodidae family. ... Binomial name Hume, 1878 The Black-nest Swiftlet (Collocalia maxima) is a species of swift in the Apodidae family. ... Genera Hydrochous Collocalia Aerodramus Schoutedenapus The birds called Swiftlets or Cave Swiftlets are contained within the four genera of Aerodramus, Hydrochous, Schoutedenapus and the remaining species left in Collocalia. ... Binomial name (Thunberg, 1812) Synonyms Collocalia fuciphaga The Edible-nest Swiftlet (Aerodramus fuciphagus) is a small bird of the swift family which is found in South-east Asia. ... Binomial name Oustalet, 1876 The Germans Swiftlet (Collocalia germani) is a species of swift in the Apodidae family. ... Binomial name Rand, 1941 The Papuan Swiftlet (Collocalia papuensis) is a species of swift in the Apodidae family. ... Binomial name (Hartert & Butler, 1901) Synonyms Hydrochrous gigas (Hartert & Butler, 1901) [orthographic error] The Waterfall Swift (Hydrochous gigas) is a species of swift in the Apodidae family. ... Binomial name (Hartert & Butler, 1901) Synonyms Hydrochrous gigas (Hartert & Butler, 1901) [orthographic error] The Waterfall Swift (Hydrochous gigas) is a species of swift in the Apodidae family. ... Schoutedenapus is a genus of swift in the Apodidae family. ... Binomial name (Salvadori, 1888) The Scarce Swift (Schoutedenapus myoptilus) is a species of swift in the Apodidae family. ... Binomial name (Prigogine, 1960) The Schoutedens Swift (Schoutedenapus schoutedeni) is a species of swift in the Apodidae family. ...

References

• Camfield, Alaine (2004) Apodidae. Animal Diversity Web (online). Accessed August 24, 2006.

• Fullard, James H. (1993): Echolocation in Free-Flying Atiu Swiftlets (Aerodramus sawtelli). Biotropica 25: 334-339. PDF fulltext

• Gausset, Quentin (2004): Chronicle of a Foreseeable Tragedy: Birds' Nests Management in the Niah Caves (Sarawak). Human Ecology 32(4): 487-506. doi:10.1023/B:HUEC.0000043517.23277.54 (HTML abstract)

• Hobbs, Joseph J. (2004): Problems in the harvest of edible birds' nests in Sarawak and Sabah, Malaysian Borneo. Biodiversity and Conservation 13(12): 2209-2226. doi:10.1023/B:BIOC.0000047905.79709.7f (HTML abstract)

• Lee, Patricia L. M.; Clayton, Dale H.; Griffiths, Richard & Page, Roderic D. M. (1996): Does behavior reflect phylogeny in swiftlets (Aves: Apodidae)? A test using cytochrome b mitochondrial DNA sequences. Proc.Natl. Acad. Sci. USA 93: 7091-7096. PDF fulltext

• Lourie, S. A. & Tompkins, D. M. (2000): The diets of Malaysian swiftlets. Ibis 142(4): 596-602. HTML abstract

• Marcone, Massimo F. (2005): Characterization of the edible bird's nest the "Caviar of the East". Food Research International 38(10) :1125-1134. doi:10.1016/j.foodres.2005.02.008 (HTML abstract)

• Price, Jordan J.; Johnson, Kevin, P.; Bush, Sarah H. & Clayton, Dale H. (2005): Phylogenetic relationships of the Papuan Swiftlet Aerodramus papuensis and implications for the evolution of avian echolocation. Ibis 147(4) 790-796. PDF fulltext

• Price, Jordan J.; Johnson, Kevin P. & Clayton, Dale H. (2004): The evolution of echolocation in swiftlets. Journal of Avian Biology 35(2): 135-143. PDF fulltext

• Thomassen, Henri A.; Tex, Robert-Jan; Bakker, Merijn A.G. & Povel, G. David E. (2005): Phylogenetic relationships amongst swifts and swiftlets: A multi locus approach. Molecular Phylogenetics and Evolution 37(1): 264-277. doi:10.1016/j.ympev.2005.05.010 (HTML abstract)

• Thomassen, Henri A. & Povel, G. David E. (2006): Comparative and phylogenetic analysis of the echo clicks and social vocalizations of swiftlets (Aves: Apodidae). Biological Journal of the Linnean Society 88(4): 631–643. doi:10.1111/j.1095-8312.2006.00648.x (HTML abstract)

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Roderic Dugald Morton Page (born 1962) is an evolutionary biologist at the University of Glasgow, Scotland, and the author of several books. ... The Proceedings of the National Academy of Sciences (USA), mostly commonly referred to as PNAS, is the official publication of the National Academy of Sciences of the United States of America. ... Ibis (ISSN print 0019-1019; online 1474-919X), subtitled the International Journal of Avian Science, is the peer-reviewed scientific journal of the British Ornithologists Union. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Ibis (ISSN print 0019-1019; online 1474-919X), subtitled the International Journal of Avian Science, is the peer-reviewed scientific journal of the British Ornithologists Union. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

Footnotes

1. ^ The Oilbird is a notable exception. The presence of echolocation was formerly used to argue for a close relationship of the Apodiformes and the oilbird, but the actual situation is more complicated. See also: Caprimulgiformes.