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Wednesday, 24 July 2019

Yellowhammer

The yellowhammer (Emberiza citrinella) is a passerine bird in the bunting family that is native to Eurasia and has been introduced to New Zealand and Australia. Most European birds remain in the breeding range year-round, but the eastern subspecies is partially migratory, with much of the population wintering further south. The male yellowhammer has a bright yellow head, streaked brown back, chestnut rump, and yellow under parts. Other plumages are duller versions of the same pattern. The yellowhammer is common in open areas with some shrubs or trees, and forms small flocks in winter. Its song has a rhythm like "A little bit of bread and no cheese". The song is very similar to that of its closest relative, the pine bunting, with which it interbreeds.
Breeding commences mainly in April and May, with the female building a lined cup nest in a concealed location on or near the ground. The three to five eggs are patterned with a mesh of fine dark lines, giving rise to the old name for the bird of "scribble lark". The female incubates the eggs for 12–14 days prior to hatching, and broods the altricial downy chicks until they fledge 11–13 days later. Both adults feed the chick in the nest and raise two or three broods each year. The nest may be raided by rodents or corvids, and the adults are hunted by birds of prey. Yellowhammers feed on the ground, usually in flocks outside the breeding season. Their diet is mainly seeds, supplemented by invertebrates in the breeding season. Changes to agricultural practices have led to population declines in western Europe, but its large numbers and huge range mean that the yellowhammer is classed as being of least concern by the International Union for Conservation of Nature.
This conspicuous yellow bird has inspired poems by Robert Burns and John Clare, and its characteristic song has influenced works by Beethoven and Messiaen. Children's writer Enid Blyton helped to popularise the standard English representation of the song.
The yellowhammer is a large bunting, 16–16.5 cm (6.3–6.5 in) long, with a 23–29.5 cm (9.1–11.6 in) wingspan; it weighs 20–36.5 g (0.71–1.29 oz). The male of the nominate subspecies E. c. citrinella has a bright yellow head, heavily streaked brown back, rufous rump, yellow under parts, and white outer tail feathers. The female is less brightly coloured, and more streaked on the crown, breast, and flanks. Both sexes are less strongly marked outside the breeding season, when the dark fringes on new feathers obscure the yellow plumage. The juvenile is much duller and less yellow than the adults, and often has a paler rump.
After breeding, adults have a complete moult, which takes at least eight weeks; males acquire more yellow in the plumage each time they moult. Juveniles have a partial moult not long after fledging, replacing the head, body, and some covert feathers.
Foraging is mainly on the ground, and the bird's diet consists mainly of seeds. Oily seeds, such as those of brassicas, are ignored in favour of more starchy items. Typical food plants include common nettle, docks, common knotgrass, fat hen, common chickweed, and yarrow. Grasses are also important, particularly cereals, and grain makes up a significant part of the food consumed in autumn and winter, wheat and oats being preferred to barley. When not breeding, yellowhammers forage in flocks that can occasionally number hundreds of birds, and often contain other buntings and finches.
The yellowhammer adds invertebrates to its diet in the breeding season, particularly as food for its growing chicks. A wide range of species is taken, including springtails, grasshoppers, flies, beetles, caterpillars, earthworms, spiders, and snails. During the first few days, chicks are exclusively fed invertebrate prey, but from day three they are also fed cereal grains, which the chicks can digest efficiently. This is thought to be intentional by the parents to allow the nestlings to adjust their physiology to eating seed.

 

(latin: Emberiza citrinella)

Wednesday, 24 July 2019