Editing Common firecrest (section)

=== Breeding ===
[[File:Regulus Ignicapilla Singing with Crest.jpg|thumb|Singing with crest displayed in a hazelnut tree. [[Capranica, Lazio|Capranica]], Italy.]]
[[File:Regulus ignicapilla MHNT.ZOO.2010.11.207.jpg|thumb|Eggs of ''Regulus ignicapilla'' – [[MHNT]]]]
The common firecrest is [[monogamy in animals|monogamous]]. The male sings during the breeding season, often with its crest raised, and has a [[display (zoology)|display]]  which involves pointing its bill at another bird, showing the crest and strong face pattern. This differs from the display of the plainer-faced goldcrest, which bows its head to emphasise the crest. The breeding territory is about {{convert|0.5|ha|acre|abbr=off}}, and may overlap with neighbouring goldcrest territories. Firecrests will sometimes defend their territories against goldcrests with the crest raised and a great deal of wing-fluttering,<ref name= Simms/> but the amount of actual competition between the species may not be very great. A Spanish study suggested that territorial conflicts between the species, and other phenomena like males singing mixed or alternating songs, were most frequent when one species locally far outnumbered the other;<ref name= Becker>{{cite journal| last= Becker | first= Peter H | year= 1977 | title= Verhalten auf Lautäußerungen der Zwillingsart, interspezifische Territorialität und Habitatansprüche von Winter- und Sommergoldhähnchen (''Regulus regulus'', ''R. ignicapillus'') |language = de | journal= Journal für Ornithologie | volume= 118 | issue = 3 | pages= 233–260 | doi = 10.1007/BF01643534| s2cid= 29890907 }}</ref> in other circumstances, the two kinglets learned to ignore each other's songs. In his courtship display the male firecrest raises his crest, points it towards his mate and hovers over her before mating takes place.<ref name= Simms/>

The nest is often suspended from a hanging branch usually at no great altitude, although [[Eric Simms (ornithologist)|Eric Simms]] reported nests at heights from {{convert|2.5|to|20|m|ft|abbr=on}}.<ref name= Simms/> Firecrests may favour breeding close to [[Eurasian goshawk]] nests. That large bird will prey on potential predators of the firecrest such as [[Eurasian sparrowhawk]]s, and nest robbers like [[eastern grey squirrel|grey squirrel]]s, [[Eurasian jay]]s and [[great spotted woodpecker]]s.<ref name= BB103>{{cite journal| last= Mawson | first= Geoff |date=April 2010| title= Apparent nesting association of Northern Goshawks and Firecrests | journal= British Birds | volume= 103 | pages= 243–244}}</ref> As is typical for the family, the [[bird nest|nest]] is a closed cup built in three layers with a small entrance hole near its top. The nest's outer layer is made from moss, small twigs, cobwebs and lichen, the spider webs also being used to attach the nest to the thin branches that support it. The middle layer is moss, and this is lined with feathers (up to 3,000) and hair.<ref name=BWP/> The nest is smaller, deeper and more compact than that of the goldcrest, about {{convert|8|cm|in|abbr=on}} across and {{convert|5|–|7|cm|in|abbr=on}} deep, with a wall thickness of about {{convert|2|cm|in|abbr=on}}.<ref name= Simms/> The nest is constructed by the female alone, although the male will accompany the female while she builds the nest over a period of a few days to three weeks.<ref name =hbw/>

Laying starts in western Europe at the end of April, and in the east of the range in late May; second [[clutch (eggs)|clutches]], which are common, commence in June to July.<ref name=BWP/> The eggs are pink with very indistinct reddish markings at the broad end,<ref name= Seebohm >{{cite book | last = Seebohm | first = Henry | author-link = Henry Seebohm | title = Coloured Figures of the Eggs of British Birds | url = https://archive.org/details/colouredfigureso00seeb | year = 1896| publisher = Sheffield: Pawson and Brailsford |page = [https://archive.org/details/colouredfigureso00seeb/page/209 209], plate 53 }}</ref> unlike those of Madeira firecrest which are described as like those of a ''[[Leaf-warbler|Phylloscopus]]'' warbler (white with some brown speckles).<ref name= Simms>{{cite book | last = Simms | first = Eric |title = British Warblers (New Naturalist Series) | year = 1985| location = London| publisher = Collins | page = 370 |isbn =978-0-00-219810-3 }}</ref> The eggs are {{convert|14|x|10|mm|in|abbr=on}} and weigh {{convert|0.7|g|oz|abbr=on}}, of which 5% is shell.<ref name = BTO>{{cite web|title= Firecrest '' Regulus ignicapilla '' [Temminck, 1820]|work= BTOWeb BirdFacts |date= 16 July 2010 | url= http://blx1.bto.org/birdfacts/results/bob13150.htm |publisher=[[British Trust for Ornithology]] |access-date=17 October 2010}}</ref> The clutch size in Europe is 7–12 eggs, but probably smaller in northwest Africa. The female incubates the eggs for 14.5 to 16.5 days to hatching, and broods the chicks, which [[fledge]] eight to ten days later. Both parents feed the chicks and fledged young.<ref name=BWP/> This species becomes sexually mature after one year, and has a life expectancy of less than two years.<ref name = BTO/>

Although their ranges overlap substantially, [[hybrid (biology)|hybridisation]] between goldcrests and firecrests seems to be prevented by differences in courtship rituals and different facial patterns. Even in aviary studies in which a female goldcrest was given an artificial eyestripe to facilitate mating with a male firecrest, the chicks were never raised by the mixed pair, and appeared to be poorly adapted compared to the parent species.<ref name =hbw/>