Editing Nest (section)

===Birds===
{{main|Bird nest}}

In general, birds are the most skilled nest builders, although not all species of birds build nests, some laying their [[egg (biology)|eggs]] directly onto rock ledges or bare soil without first modifying the area.  Complex nest building is considered to be one of the key adaptive advantages of birds.<ref name=SDNMH />  Nests help regulate temperature and reduce predation risks, thus increasing the chance that offspring live to adulthood.<ref name=Hansell />

Bird nests vary from simple depressions in the ground known as scrapes to largely unstructured collections of branches to elaborately woven pendants or spheres.  The [[megapode]]s, one of the few groups who do not directly brood their young, incubate their young in a mound of decomposing vegetation.  One species, ''[[Macrocephalon maleo]]'', uses volcanic sand warmed by geothermal heat to keep its eggs warm.<ref name=SDNMH />  Among the simple nest builders are [[falcon]]s, [[owl]]s, and many [[shorebird]]s.  The [[Ploceidae|weavers]] exhibit perhaps the most elaborate nests, complete with strands of grass tied into knots.  Most bird nests lie somewhere in the middle, with the majority building cup-shaped nests using some combination of mud, twigs and leaves, and feathers.  Some birds, such [[flamingo]]s and [[Swift (bird)|swifts]], use saliva to help hold their nest together.  The [[edible-nest swiftlet]] uses saliva alone to construct their nests.<ref name=Britannica />  The [[rufous hornero]] nest is composed entirely of mud and feces, which is placed on tree branches to allow the sun to harden it into a usable structure.<ref name=PopMech /> The [[tailorbird]]s stitch together leaves to provide cover for their nest sites.<ref name=SDNMH />

[[File:Webervogelnst Auoblodge.JPG|thumb|left|A single nesting colony of the sociable weaver may house hundreds of individuals]]
The [[sociable weaver]] builds large communal nests in which many individual nests reside.  They divide the nest using walls of grass placed atop a base of large sticks.  At the entrances to the nest, sharp sticks are placed to ward off intruders.<ref name=PopMech /> A single communal site can measure {{convert|2|m|ft}} in height and {{convert|8|m|ft}} in width.  As many as 300 mating pairs may reside in the structure.<ref name=populous>{{cite web|title=Most populous bird's nest|work=Guinness World Records|url=http://www.guinnessworldrecords.com/world-records/12000/most-populous-bird%E2%80%99s-nest|access-date=August 20, 2013|url-status=live|archive-url=https://web.archive.org/web/20140821031439/http://www.guinnessworldrecords.com/world-records/12000/most-populous-bird%E2%80%99s-nest|archive-date=August 21, 2014}}</ref>  Other birds often built their own nests on top of Weaver nest sites.<ref name=PopMech />

Some birds build nests in [[tree]]s, some (such as [[eagle]]s, [[vulture]]s, and many [[seabird]]s) will build them on rocky ledges, and others nest on the ground or in [[burrow]]s.<ref name=Britannica />  Each species has a characteristic nest style, but few are particular about where they build their nests.  Most species will choose whatever site in their environment best protects their nest, taking into account the nest's style.  Several species will build on a cactus whenever possible.  The [[bushtit]] and [[Bullock's oriole]] will suspend their nests from the tips of slender branches.<ref name=SDNMH />  The [[oropendola]]s take hanging nests to the extreme, constructing pouches up to {{convert|1.8|m|ft}} tall using hanging vines as their base.<ref name=SDNMH /><ref name=PopMech />  The hanging nest is attached to thin tree branches, discouraging predation.<ref name=PopMech />  Other species seek out crevices, using buildings or birdhouses when tree holes are not available.<ref name=SDNMH />

Typical bird nests range from {{convert|2|cm|in}} in size ([[hummingbird]]s) to {{convert|2|m|ft}} ([[eagle]]s) in diameter.<ref name=Britannica />  The largest nest on record was made by a pair of [[bald eagles]].  It was {{convert|2.9|m|ft}} in diameter, {{convert|6|m|ft}} deep and was estimated to weigh more than {{convert|2|t|lb}}.<ref name=largest>{{cite web|title=Largest bird's nest|work=Guinness World Records|url=http://www.guinnessworldrecords.com/world-records/10000/largest-birds-nest|access-date=August 20, 2013}}</ref>  The lightest bird nests may weigh only a few grams.<ref name=Britannica />  Incubation mounds of the [[mallee fowl]] can reach heights of {{convert|4.57|m|ft}} and widths of {{convert|10.6|m|ft}}.  It is estimated the animal uses as much as {{convert|300|t|lb}} of material in its construction.<ref name= populous />  The extinct ''[[Sylviornis neocaledoniae]]'' may have constructed nesting mounds {{convert|50|m|ft}} in diameter.<ref name=Hansell />