Editing Swiftlet (section)

== Description and ecology ==
The swift family remains one of the more complicated groups of birds in [[Taxonomy (biology)|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 [[flight feather|primary feathers]] and small breast muscles.  The larger ''Aerodramus'' swiftlets weigh about 14 grams and are 10&nbsp;cm long.

Swiftlets are insectivores; [[hymenoptera]]ns and [[diptera]]ns being the most abundant prey.<ref name=Lourie/> 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 [[Bird colony|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]], [[Malaysia]]n [[Borneo]].

The genus ''Aerodramus'' is of special interest due to its use of [[Animal echolocation|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,<ref name=Hobbs/><ref name=Marcone/> but other authorities<ref name=Jordan/> have shown that modern techniques of nest farming have increased the bird population.

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.<ref name=Price2004/> Characteristics of behavior, such as what materials other than saliva the nests contain, can be used to differentiate between certain species of ''Aerodramus''.<ref name=Lee/>