{{Short description|Family of birds}} {{Use dmy dates|date=August 2015}} {{Automatic taxobox | name = Kinglets | image = Regulus regulus japonensis face.JPG | image_caption = Goldcrest (''Regulus regulus'') in Japan | parent_authority = | display_parents = 2 | taxon = Regulidae | authority = Vigors, 1825 | subdivision_ranks = Genera | subdivision = * ''Corthylio'' * ''Regulus'' }}
The '''kinglets''' or '''crests''' are small birds in the family '''Regulidae'''. Species in this family were formerly classified with the Old World warblers. "Regulidae" is derived from the Latin word ''regulus'', diminutive for "king", and refers to the coloured crowns of adult birds. This family has representatives in Eurasia and North America. There are six species in this family; one, the Madeira firecrest (''Regulus madeirensis''), was only recently split from the common firecrest as a separate species. The ruby-crowned kinglet differs sufficiently in its voice and plumage to be afforded its own genus, ''Corthylio''.
==Description== Kinglets are among the smallest of all passerines, ranging in size from {{convert|8|to|11|cm|in|round=0.5|abbr=on}} and weighing {{convert|6|-|8|g|oz|abbr=on}}; the sexes are the same size. They have medium-length wings and tails, and small needle-like bills. The plumage is overall grey-green, offset by pale wingbars, and the tail tip is incised. Five species have a single stiff feather covering the nostrils, but in the ruby-crowned kinglet this is replaced by several short, stiff bristles. Most kinglets have distinctive head markings, and the males possess a colourful crown patch. In the females, the crown is duller and yellower. The long feathers forming the central crown stripe can be erected; they are inconspicuous most of the time, but are used in courtship and territorial displays when the raised crest is very striking.<ref name="hbw">Martens, Jochen; Päckert, Martin "Family Regulidae (Kinglets & Firecrests)" pp. 330–349 in {{cite book|title=Handbook of the Birds of the World, Volume 11: Old World Flycatchers to Old World Warblers|title-link=Handbook of the Birds of the World|publisher=Lynx Edicions|year=2006|isbn=978-84-96553-06-4|editor-last=Del Hoyo|editor-first=Josep|location=Barcelona, Spain|editor2-last=Elliott|editor2-first=Andrew|editor3-last=Christie|editor3-first=David A.}}</ref>
There are two species of different genera in North America with largely overlapping distributions, and two in Eurasia that also have a considerable shared range; the remaining two, at opposite ends of Eurasia, are island endemics. In each continent, one species (goldcrest in Eurasia and golden-crowned kinglet in North America) is a conifer specialist; these have deeply grooved pads on their feet for perching on conifer twigs and a long hind toe and claw for clinging vertically. The two generalists, ruby-crowned kinglet and common firecrest, hunt more in flight and have smoother soles, shorter hind claws and a longer tail.<ref name = hbw/>
==Taxonomy== Recent molecular studies have clarified the phylogeny of the Regulidae; they are now placed in their own superfamily '''Reguloidea''', near-basal in the infraorder Passerides, the "higher songbirds", with their closest relatives probably the family Elachuridae and the superfamily Bombycilloidea (waxwings and allies).<ref name="Fjeldså">{{cite book | last1=Fjeldså | first1=Jon | last2=Christidis | first2=Les | last3=Ericson | first3=Per G. P. | title=The Largest Avian Radiation | publisher=Lynx edicions | publication-place=Barcelona | date=2020 | isbn=978-84-16728-33-6 | pages=180–181}}</ref>
The kinglets were first allocated to the warbler genus ''Sylvia'' by English naturalist John Latham in 1790,<ref name= latham>{{cite book| last = Latham | first = John | title = Index ornithologicus, sive, Systema ornithologiae, complectens avium divisionem in classes, ordines, genera, species, ipsarumque varietates, adjectis synonymis, locis, descriptionibus, &c | year = 1790 | location = London | publisher = Leigh & Sotheby | language = la | page = 548 | volume = ii }}</ref> but moved to their current genus by French zoologist Georges Cuvier in 1800.<ref name= cuvier>{{cite book| last = Cuvier | first = Georges | title = Lecons d'anatomie comparee de M. G. Cuvier, Recueillies et publiees sous ses yeux, par C. Dumeril et Duvernoy | year = 1800 | location = Paris | publisher = Crochard et cie | language = fr | volume = 1, table 2 }}</ref> They were formerly usually included in the Old World warblers but were given family status when it was found, that despite superficial similarities, they are phylogenetically remote from the warblers.<ref name= Barker>{{cite journal | last= Barker | first= F Keith |author2=Barrowclough, George F |author3=Groth, Jeff G | year = 2002 | title= A phylogenetic hypothesis for passerine birds: taxonomic and biogeographic implications of an analysis of nuclear DNA sequence data | journal= Proceedings of the Royal Society of London B | volume= 269 | pages= 295–308 | url= | doi = 10.1098/rspb.2001.1883 | pmid=11839199 | pmc=1690884 | issue=1488}}</ref><ref name= Spicer>{{cite journal | last= Spicer | first= Greg S | author2= Dunipace, Leslie | year= 2004 | title= Molecular phylogeny of songbirds (Passerifor-mes) inferred from mitochondrial 16S ribosomal RNA gene sequences | pmid= 14715224 | doi= 10.1016/S1055-7903(03)00193-3 | journal= Molecular Phylogenetics and Evolution | volume= 30 | issue= 2 | pages= 325–335 | bibcode= 2004MolPE..30..325S | url= http://online.sfsu.edu/~gs/spicer/pages/spicerpdf/spicerdunipace04.pdf | access-date= 24 November 2010 | archive-date= 4 March 2012 | archive-url= https://web.archive.org/web/20120304150636/http://online.sfsu.edu/~gs/spicer/pages/spicerpdf/spicerdunipace04.pdf | url-status= dead }}</ref><ref name="Fjeldså"/>
Most members of the genus ''Regulus'' are similar in size and colour pattern. The exception is the ruby-crowned kinglet, the largest species, which has a strongly red crest and no black crown stripes. It has distinctive vocalisations, and is different enough from the Old World kinglets and the other American species, the golden-crowned kinglet, to be assigned to a separate genus, ''Corthylio''.<ref name="hbw" /><ref>{{Cite journal | last1=Chesser | first1=R.T. | last2=Billerman | first2=S.M. | last3=Burns | first3=K.J. | last4=Cicero | first4=C. | last5=Dunn | first5=J.L. | last6=Hernández-Baños | first6=B.E. | last7=Kratter | first7=A.W. | last8=Lovette | first8=I.J. | last9=Mason | first9=N.A. | last10=Rasmussen | first10=P.C. | last11=Remsen | first11=J.V.J. | last12=Stotz | first12=D.F. | last13=Winker | first13=K. | date=2021 | title=Sixty-second Supplement to the American Ornithological Society's Check-list of North American Birds | journal=Ornithology | volume=138 | issue=ukab037 | article-number=ukab037 | doi=10.1093/ornithology/ukab037 | doi-access=free }}</ref><ref name="ioc">{{cite web| editor1-last=Gill | editor1-first=Frank | editor1-link=Frank Gill (ornithologist) | editor2-last=Donsker | editor2-first=David | editor3-last=Rasmussen | editor3-first=Pamela | editor3-link=Pamela Rasmussen | date=July 2021 | title=Dapple-throats, sugarbirds, fairy-bluebirds, kinglets, Elachura, hyliotas, wrens, gnatcatchers | work=IOC World Bird List Version 11.2 | url=https://www.worldbirdnames.org/bow/sugarbirds/ | publisher=International Ornithologists' Union | accessdate=20 July 2021 }}</ref>
===Species in taxonomic order=== {| class="wikitable sortable" |- ! Image !! Common name !! Scientific name !! Distribution |- |120px || Ruby-crowned kinglet || ''Corthylio calendula'' || North America. Three subspecies. |- |120px || Common firecrest || ''Regulus ignicapilla'' || Europe, southwest Asia, northwest Africa. Four subspecies. |- |120px || Madeira firecrest || ''Regulus madeirensis'' || Madeira (endemic). Monotypic. |- |120px || Golden-crowned kinglet || ''Regulus satrapa'' || North America. Five subspecies. |- |120px || Flamecrest || ''Regulus goodfellowi'' || Taiwan (endemic). Monotypic. |- |120px || Goldcrest || ''Regulus regulus'' || Europe, Asia. Fourteen subspecies. |- |}
==Etymology== The name of the family derives from the Latin ''regulus'', a diminutive of ''rex'', "a king",<ref name = Chambers>{{cite book | editor-last = Brookes| editor-first = Ian | title = The Chambers Dictionary, ninth edition | year =2006 | publisher = Chambers | location = Edinburgh | pages = 223, 735, 1277 | isbn = 978-0-550-10185-3| title-link = Chambers Dictionary }}</ref> and refers to the characteristic orange or yellow crests of adult kinglets (aside from the red crest of ''Corthylio'').
== Distribution and habitat == Kinglets are birds of the Nearctic and Palearctic realms, with representatives in temperate North America, Europe and Asia, northernmost Africa, Macaronesia and the Himalayas. They are adapted to conifer forests, although there is a certain amount of adaptability and most species will use other habitats, particularly during migration. In Macaronesia, they are adapted to laurisilva and tree heaths.<ref name =hbw/>
==Behaviour==
===Diet and feeding=== The tiny size and rapid metabolism of kinglets means that they must constantly forage in order to provide their energy needs. They will continue feeding even when nest building. Kinglets prevented from feeding may lose a third of their body weight in twenty minutes and may starve to death in an hour.{{cn|date=November 2025}} Kinglets are insectivores, preferentially feeding on prey such as aphids and springtails that have soft cuticles. Prey is generally gleaned from the branches and leaves of trees, although in some circumstances prey may be taken on the wing or from the leaf litter on the ground.
===Life cycle=== Kinglet nests are small, very neat cups, almost spherical in shape, made of moss and lichen held together with spiderwebs and hung from twigs near the end of a high branch of a conifer. They are lined with hair and feathers, and a few feathers are placed over the opening. These characteristics provide good insulation against the cold environment. The female lays 7 to 12 eggs, which are white or pale buff, some having fine dark brown spots. Because the nest is small, they are stacked in layers. The female incubates; she pushes her legs (which are well supplied with blood vessels, hence warm) down among the eggs. A unique feature of kinglets is the "size hierarchy" among eggs, with early-laid eggs being smaller than later ones.<ref>Haftorn, Svein; "Clutch size, intraclutch egg size variation, and breeding strategy in the Goldcrest ''Regulus regulus''"; in ''Journal of Ornithology'', Volume 127, Number 3 (1986), 291-301.</ref>
Eggs hatch asynchronously after 15 to 17 days. The young stay in the nest for 19 to 24 days. After being fed, nestlings make their way down to the bottom of the nest, pushing their still-hungry siblings up to be fed in their turn (but also to be cold).
Kinglets are the most fecund and shortest-living of all altricial birds,<ref>Sibly Richard M., Witt, Christopher C., Wright, Natalie A., Venditti, Chris, Jetze, Walter and Brown, James H.; [http://biology.unm.edu/witt/pub_files/PNAS-2012-Sibly-etal-Avian-productivity.pdf "Energetics, lifestyle, and reproduction in birds"] {{Webarchive|url=https://web.archive.org/web/20140719215519/http://biology.unm.edu/witt/pub_files/PNAS-2012-Sibly-etal-Avian-productivity.pdf |date=19 July 2014 }}; in ''Proceedings of the National Academy of Sciences''; 109 (27); pp. 10937-10941</ref> and probably the shortest-lived apart from a few smaller galliform species. Adult mortality for the goldcrest is estimated at over 80 percent per year<ref>In Ricklefs, R.E.; "Sibling competition, hatching asynchrony, incubation period, and lifespan in altricial birds"; in Power, Dennis M. (editor); ''Current Ornithology''. Vol. 11. {{ISBN|9780306439902}}</ref> and the maximum lifespan is only six years.<ref>Wasser, D. E. and Sherman, P.W.; "Avian longevities and their interpretation under evolutionary theories of senescence" in ''Journal of Zoology'' 2 November 2009</ref>
==References== {{Reflist}}
==External links== {{Commons|Regulus}} {{Commons|Regulidae}} *[http://ibc.lynxeds.com/family/cotingas-cotingidae Kinglet videos] on the Internet Bird Collection
{{Kinglets}}
{{Taxonbar|from1=Q118959217}}
* Category:Regulus (bird) Category:Taxa named by Georges Cuvier