Common firecrest

Appearance

The common firecrest is a small plump bird, 9 cm in length with a wingspan of 13–16 cm, and weighs 4–7 grams. It has bright olive-green upperparts with a bronze-coloured patch on each shoulder, and whitish underparts washed with brownish-grey on the breast and flanks. It has two white wingbars, a tiny black pointed bill, and brownish-black legs.

The head pattern is striking, with a black eye stripe, long white supercilium, and a crest which is bright yellow in the female and mainly orange in the male. The sexes are very similar, apart from the crest colour, although the female is a little duller in plumage and on average slightly smaller.

Juveniles have a grey tinge to the duller upperparts, and lack the coloured crown; the other head markings are present, but duller than in the adult. By their first winter, only the flight and tail feathers remain unmoulted, and the young birds are virtually indistinguishable from the adults in the field. This kinglet usually hops with its body held horizontally, and its flight is weak and whirring, with occasional quick evasive turns.

Status

The common firecrest has a large range and a population estimated at 10–30 million individuals, most in Europe. The population is believed to be stable in the absence of evidence for any declines or serious threats, and it is therefore classed as least concern on the IUCN Red List.

Habitat

The common firecrest breeds in lowland broadleaf forest, preferring cork oak and alder where available, otherwise beech and holly. It also uses mixed broadleaf and conifer woodland, and stands of spruce, European silver fir, cedar and pines, often with undergrowth of juniper, ivy and wild rose. In drier Mediterranean habitats it is found in conifers, evergreen oak, and mixed woodlands up to 2,800 m.

Reproduction

The common firecrest is monogamous. The male sings during the breeding season, often with its crest raised, and has a 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 0.5 hectares, 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, 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; 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.

The nest is often suspended from a hanging branch usually at no great altitude, although Eric Simms reported nests at heights from 2.5 to 20 m. Firecrests may favour breeding close to northern goshawk nests. That large bird will prey on potential predators of the firecrest such as Eurasian sparrowhawks, and nest robbers like grey squirrels, Eurasian jays and great spotted woodpeckers. As is typical for the family, the 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 and hair. The nest is smaller, deeper and more compact than that of the goldcrest, about 8 cm across and 5–7 cm deep, with a wall thickness of about 2 cm. 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.

Laying starts in western Europe at the end of April, and in the east of the range in late May; second clutches, which are common, commence in June to July. The eggs are pink with very indistinct reddish markings at the broad end, unlike those of Madeira firecrest which are described as like those of a "Phylloscopus" warbler. The eggs are 14 mm × 10 mm and weigh 0.7 g, of which 5% is shell. 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. This species becomes sexually mature after one year, and has a life expectancy of less than two years.

Food

All species of kinglet are almost exclusively insectivorous, preying on small arthropods with soft cuticles, such as springtails, aphids and spiders. They also feed on the cocoons and eggs of spiders and insects, and occasionally take pollen. All species will hover to catch flying insects. Although the similarly sized firecrest and goldcrest are often found together, there are a number of factors that reduce direct competition for food. Common firecrests prefer larger prey than goldcrests. Although both will take trapped insects from spider webs on autumn migration, firecrests will also eat the large orb-web spiders.

Predators

Throughout the firecrest's range, the main predator of small woodland birds is the Eurasian sparrowhawk, which takes avian prey as up to 98% of its diet. The tawny owl relies more on mammalian catches, but about one-third of its food is forest birds. Eggs and young may be taken by grey squirrels, Eurasian jays and great spotted woodpeckers. The firecrest appears to be virtually unknown as a host of the common cuckoo, a widespread European brood parasite.

The invasive Argentine ant is common in the Mediterranean area, and reduces arthropod numbers by removing most native ant species. The reduction in prey items is greatest in the tree canopy, and has a greater effect on species like the firecrest that feed high in the foliage. Less food is available for chicks, and parents have to spend more time foraging.

Data on specific parasites of the firecrest is lacking, but the widespread moorhen flea, "Dasypsyllus gallinulae" has been recorded in a related "Regulus" species. A number of feather mites have been recorded in the genus, including "Proctophyllodes glandarinus" on firecrest. These mites live on fungi growing on the feathers....hieroglyph snipped... The fungi found on the plumage may feed on the keratin of the outer feathers or on feather oil.