The Eurasian blackcap is a small widespread songbird. It has mainly olive-grey upperparts and pale grey underparts. Both sexes have a neat colored cap to the head, black in the male and reddish-brown in the female. The rich and varied song of this bird has led to it being described as the "mock nightingale" and it has featured in literature, films, and music.
Eurasian blackcaps breed in much of Europe, western Asia, and northwestern Africa. They are partial migrants; birds from the colder areas of their range winter in northwestern Europe, around the Mediterranean, and in tropical Africa. Some German birds have adapted to spending the winter in gardens in Great Britain and Ireland. Eurasian blackcaps breed in mature deciduous woodlands, with the good scrub cover below the trees, and may also be found in parks, large gardens, and overgrown hedges. The preferred winter habitat around the Mediterranean is scrub and olive orchards, while in Africa they occur in cultivated land, acacia scrub, mangroves, and forest.
Eurasian blackcaps are very active birds. They are usually found singly but may form loose groups during migration. They feed by the day mainly picking prey off foliage and twigs, but may occasionally hover, flycatch or feed on the ground. Blackcaps eat a wide range of small fruit and squeeze out any seeds on a branch before consuming the pulp. They defend good winter food sources, and at garden feeding stations they don't hesitate to repel competitors as large as starlings and blackbirds. Eurasian blackcaps are known for their beautiful loud song. The males' song is a rich musical warbling, often ending in a loud high-pitched crescendo, which is given in bursts of up to 30 seconds. In some geographically isolated areas, such as islands, peninsulas, and valleys in the Alps, males sing a simpler fluting song. The main call of Eurasian blackcaps is a hard 'tac-tac', like stones knocking together, and other vocalizations include a squeaking sweet alarm, and a low-pitched trill. Blackcaps may sometimes mimic the song of other birds, especially preferring to copy the garden warbler and the common nightingale.
Eurasian blackcaps are carnivores (insectivores) and herbivores (frugivores). They feed mainly on insects and larvae during the breeding season and switch to fruit in late summer. They also take berries, pollen, and nectar. Blackcaps will also eat small snails which they swallow whole since the shell is a source of calcium for the bird's eggs. Chicks are mainly fed soft-bodied insects, fruit only if invertebrates are scarce.
Eurasian blackcaps are monogamous and form pairs. They breed between mid-April and August. When males return to their breeding areas, they establish a territory by singing loudly while displaying with the crown raised, tail fanned, and slow wingbeats. This display is followed, if necessary, by a chase, often leading to a fight. A male then attracts a female to his territory through song and a display involving raising the black crown feathers, fluffing the tail, slow wingbeats, and a short flapping flight. He also builds one or more simple nests (cock nests), usually near his songpost. The final nest, which may be one of the cock nests or built from scratch, is a neat cup of roots, stems, and grasses lined with fine material such as hair. The nest is typically built in the cover of bramble, scrubs, or trees. It is constructed mainly by the female and may be between 1-4.5 m (3.3-15 ft) above the ground. The clutch is typically 4-6 eggs, which are usually buff with grey and brown blotches and a few dark brown spots. The eggs are incubated for 10-16 days by both parents. Males will sometimes sing even when incubating and this may also be intended to maintain the bond with the female. The chicks are altricial, hatching naked and with closed eyes, and are fed by both parents. They fledge about 11-12 days after hatching, leaving the nest shortly before they are able to fly. They are assisted with feeding for a further 2 or 3 weeks. If the nest is threatened, the non-incubating bird gives an alarm call so that the sitting parent and chicks stay still and quiet. A male blackcap may mob a potential predator, or try to lure it away with disjointed runs and flaps on the ground. Young Eurasian blackcaps usually start to breed when they are one year old.
Eurasian blackcaps are not globally threatened at present. However, they are illegally trapped and hunted in large numbers in Mediterranean countries, particularly in Lebanon, Syria, Palestine, Malta, Libya, Egypt, and Cyprus, where they are considered as a delicacy.
According to the IUCN Red List, the total population size of the Eurasian blackcap is 101,000,000-161,000,000 mature individuals. In Europe, the breeding population consists of 40,500,000-64,500,000 pairs, which equates to 81,000,000-129,000,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are increasing.