Editing Bird (section)

====Parental care and fledging====
{{Main|Parental care in birds}}
At the time of their hatching, chicks range in development from helpless to independent, depending on their species. Helpless chicks are termed ''[[altricial]]'', and tend to be born small, [[Blindness|blind]], immobile and naked; chicks that are mobile and feathered upon hatching are termed ''[[precocial]]''. Altricial chicks need help [[thermoregulation|thermoregulating]] and must be brooded for longer than precocial chicks. The young of many bird species do not precisely fit into either the precocial or altricial category, having some aspects of each and thus fall somewhere on an "altricial-precocial spectrum".<ref name="Urfi2011">{{cite book|last=Urfi|first=A. J.|title=The Painted Stork: Ecology and Conservation|url=https://books.google.com/books?id=_9tczTapYXMC&pg=PA88|year=2011|publisher=Springer Science & Business Media|isbn=978-1-4419-8468-5|page=88}}</ref> Chicks at neither extreme but favouring one or the other may be termed {{Birdgloss|semi-precocial}}<ref name="Khanna2005">{{cite book|last=Khanna|first=D. R.|title=Biology of Birds|url=https://books.google.com/books?id=fDblIChi7KwC&pg=PA109|year=2005|publisher=Discovery Publishing House|isbn=978-81-7141-933-3|page=109}}</ref> or {{Birdgloss|semi-altricial}}.<ref name="Scott2008">{{cite book|last=Scott|first=Lynnette|title=Wildlife Rehabilitation|url=https://books.google.com/books?id=FpAOAQAAMAAJ|year=2008|publisher=National Wildlife Rehabilitators Association|isbn=978-1-931439-23-7|page=50}}</ref>
[[File:White-breasted Woodswallow chicks in nest.jpg|thumb|alt=Looking down on three helpless blind chicks in a nest within the hollow of a dead tree trunk|right|[[Altricial]] chicks of a [[white-breasted woodswallow]]]]

The length and nature of parental care varies widely amongst different orders and species. At one extreme, parental care in [[megapode]]s ends at hatching; the newly hatched chick digs itself out of the nest mound without parental assistance and can fend for itself immediately.<ref>{{cite book |last1=Elliot |first1=A |year=1994 |chapter=Family Megapodiidae (Megapodes) |title=Handbook of the Birds of the World |series=Vol. 2: New World Vultures to Guineafowl |editor-last1=del Hoyo |editor-first1=J. |editor-last2=Elliott |editor-first2=A. |editor-last3=Sargatal |editor-first3=J. |publisher=Lynx Edicions |location=Barcelona |isbn=84-87334-15-6 |title-link=Handbook of the Birds of the World }}</ref> At the other extreme, many seabirds have extended periods of parental care, the longest being that of the [[great frigatebird]], whose chicks take up to six months to [[fledge]] and are fed by the parents for up to an additional 14 months.<ref>{{cite book |last1=Metz |first1=V. G. |last2=Schreiber |first2=E. A. |year=2002|chapter=Great Frigatebird (''Fregata minor'') |title=The Birds of North America, No 681 |editor-last1=Poole |editor-first1=A. |editor-last2=Gill |editor-first2=F. |publisher=The Birds of North America Inc |location=Philadelphia}}</ref> The ''chick guard stage'' describes the period of breeding during which one of the adult birds is permanently present at the nest after chicks have hatched. The main purpose of the guard stage is to aid offspring to thermoregulate and protect them from predation.<ref>{{cite book |last1=Young |first1=Euan |title=Skua and Penguin. Predator and Prey |publisher=Cambridge University Press |year=1994 |page=453}}</ref>
[[File:Calliope-nest edit.jpg|thumb|alt=Hummingbird perched on edge of tiny nest places food into mouth of one of two chicks|left|A female [[calliope hummingbird]] feeding fully grown chicks]]
In some species, both parents care for nestlings and fledglings; in others, such care is the responsibility of only one sex. In some species, [[helpers at the nest|other members]] of the same species—usually close relatives of the [[breeding pair]], such as offspring from previous broods—will help with the raising of the young.<ref>{{cite journal | last1 = Ekman | first1 = J. | year = 2006 | title = Family living amongst birds | journal = [[Journal of Avian Biology]] | volume = 37 | issue = 4| pages = 289–298 | doi = 10.1111/j.2006.0908-8857.03666.x }}</ref> Such [[alloparenting]] is particularly common among the [[Corvida]], which includes such birds as the true [[Corvidae|crows]], [[Australian magpie]] and [[fairy-wren]]s,<ref>{{Cite book|vauthors=Cockburn A |veditors=Floyd R, Sheppard A, de Barro P |title=Frontiers in Population Ecology|year=1996|publisher=CSIRO|location=Melbourne|pages=21–42|chapter=Why do so many Australian birds cooperate? Social evolution in the Corvida}}</ref> but has been observed in species as different as the [[Rifleman (bird)|rifleman]] and [[red kite]]. Among most groups of animals, [[Paternal care|male parental care]] is rare. In birds, however, it is quite common—more so than in any other vertebrate class.<ref name = "Gill"/> Although territory and nest site defence, incubation, and chick feeding are often shared tasks, there is sometimes a [[division of labour]] in which one mate undertakes all or most of a particular duty.<ref>{{Cite journal|last=Cockburn|first=Andrew|year=2006|title=Prevalence of different modes of parental care in birds |doi=10.1098/rspb.2005.3458|journal=[[Proceedings of the Royal Society B]]|volume=273|issue=1592|pages=1375–1383|pmid=16777726|pmc=1560291}}</ref>

The point at which chicks [[fledge]] varies dramatically. The chicks of the ''[[Synthliboramphus]]'' murrelets, like the [[ancient murrelet]], leave the nest the night after they hatch, following their parents out to sea, where they are raised away from terrestrial predators.<ref>{{cite book |last1=Gaston |first1=AJ |year=1994 |chapter=Ancient Murrelet (''Synthliboramphus antiquus'') |title=The Birds of North America, No. 132 |editor-first1=A. |editor-last1=Poole |editor-first2=F. |editor-last2=Gill |location=Philadelphia & Washington, D.C. |publisher=The Academy of Natural Sciences & The American Ornithologists' Union}}</ref> Some other species, such as ducks, move their chicks away from the nest at an early age. In most species, chicks leave the nest just before, or soon after, they are able to fly. The amount of parental care after fledging varies; albatross chicks leave the nest on their own and receive no further help, while other species continue some supplementary feeding after fledging.<ref>{{cite journal | last1 = Schaefer | first1 = H. C. | last2 = Eshiamwata | first2 = G. W. | last3 = Munyekenye | first3 = F. B. | last4 = Böhning-Gaese | first4 = K. | year = 2004 | title = Life-history of two African ''Sylvia'' warblers: low annual fecundity and long post-fledging care | journal = [[Ibis (journal)|Ibis]] | volume = 146 | issue = 3| pages = 427–437 | doi = 10.1111/j.1474-919X.2004.00276.x }}</ref> Chicks may also follow their parents during their first [[bird migration|migration]].<ref>{{cite journal | last1 = Alonso | first1 = J. C. | last2 = Bautista | first2 = L. M. | last3 = Alonso | first3 = J. A. | year = 2004 | title = Family-based territoriality vs flocking in wintering common cranes ''Grus grus'' | journal = [[Journal of Avian Biology]] | volume = 35 | issue = 5| pages = 434–444 | doi = 10.1111/j.0908-8857.2004.03290.x | hdl = 10261/43767 }}</ref>