Editing Bird nest (section)

{{short description|Place where a bird broods its eggs}}
{{About||animal nests in general|Nest|other uses|Bird's nest (disambiguation){{!}}Bird's nest}}
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{{Use dmy dates|date=July 2021}}

[[File:Acrocephalus arundinaceus nest (cropped).jpg|thumb|right|Deep cup nest of the [[great reed-warbler]]]]

A '''bird nest''' is the spot in which a bird lays and [[Avian incubation|incubates]] its [[Bird egg|eggs]] and raises its young. Although the term popularly refers to a specific [[structures built by animals|structure]] made by the bird itself—such as the grassy cup nest of the [[American robin]] or [[Eurasian blackbird]], or the elaborately woven hanging nest of the [[Montezuma oropendola]] or the [[village weaver]]—that is too restrictive a definition. For some species, a nest is simply a shallow depression made in sand; for others, it is the knot-hole left by a broken branch, a burrow dug into the ground, a chamber drilled into a tree, an enormous rotting pile of vegetation and earth, a shelf made of dried saliva or a mud dome with an entrance tunnel. The smallest bird nests are those of some [[hummingbird]]s, tiny cups which can be a mere {{convert|2|cm|in|1|abbr=on}} across and {{convert|2|–|3|cm|in|1|abbr=on}} high.<ref name="Campbell386">{{Harvnb|Campbell|Lack|1985|p=386}}</ref> At the other extreme, some nest mounds built by the [[dusky scrubfowl]] measure more than {{convert|11|m|ft|abbr=on}} in diameter and stand nearly {{convert|5|m|ft|abbr=on}} tall.<ref>{{Harvnb|Campbell|Lack|1985|p=345}}</ref> The study of birds' nests is known as ''caliology''.

Not all bird species build nests. Some species lay their eggs directly on the ground or rocky ledges, while [[brood parasites]] lay theirs in the nests of other birds, letting unwitting "foster parents" do the work of rearing the young. Although nests are primarily used for breeding, they may also be reused in the non-breeding season for roosting and some species build special ''dormitory nests'' or ''roost nests'' (or ''winter-nest'') that are used only for roosting.<ref name=skutch>{{Citation|title=The nest as a dormitory|last=Skutch |first=Alexander F|journal=Ibis| volume=103| issue=1 | pages=50–70 | doi=10.1111/j.1474-919X.1961.tb02420.x| year=1960|postscript=.}}</ref> Most birds build a new nest each year, though some refurbish their old nests.<ref>[http://smithsonianscience.org/2015/04/bird-nests-variety-is-key-for-avian-architects smithsonianscience.org 2015-04-20 Bird nests: Variety is Key for the world's avian Architects] {{webarchive|url=https://web.archive.org/web/20170103173244/http://insider.si.edu/2015/04/bird-nests-variety-is-key-for-avian-architects/ |date=3 January 2017 }}</ref> The large '''eyries''' (or '''aeries''') of some eagles are platform nests that have been used and refurbished for several years.

In the majority of nest-building species the female does most or all of the nest construction, in others both partners contribute; sometimes the male builds the nest and the hen lines it.<ref>{{Harvnb|Campbell|Lack|1985|p=387}}</ref><ref>{{cite book |last1=Felix |first1=Jiri |title=Garden and Field Birds |date=1973 |publisher=Octopus books |isbn=0-7064-0236-7 |page=17}}</ref> In some [[Polygyny in animals|polygynous]] species, however, the male does most or all of the nest building. The nest may also form a part of the courtship display such as in [[Ploceidae|weaver birds]]. The ability to choose and maintain good nest sites and build high quality nests may be selected for by females in these species. In some species the young from previous broods may also act as [[Helpers at the nest|helpers]] for the adults.