European Greenfinch

The European greenfinch (Chloris chloris) is a heavy-set finch with a large head and a powerful conical bill adapted for cracking seeds. Adults are about 15 cm long and weigh around 28 g. Males are yellow-green with brighter yellow panels in the wings and tail, while females are greyer and more subdued. Both sexes show the yellow wing and tail markings particularly clearly in flight.

The song combines twittering phrases with a distinctive drawn-out, nasal wheeze. Males may also perform a slow song flight with stiff, shallow wingbeats over the breeding territory, making the species conspicuous even when the bird itself is partly hidden among trees and shrubs.

Greenfinches favour open, partly wooded landscapes with dense shrubs or trees for nesting. Farmland, hedgerows, woodland edges, orchards, parks, cemeteries and gardens are all typical habitats, and the species readily lives close to people.

Good habitat combines secure nesting cover with open feeding areas and abundant seed-producing plants. This makes structurally varied suburbs and traditional farmland especially suitable, while very dense forest and completely open landscapes with little woody cover are generally less favourable.

Adults are strongly seed-eating throughout the year. The broad bill allows them to crack and process a wide range of seeds, including those of weeds, grasses, trees and cultivated plants. Berries and other plant material are also taken, and greenfinches readily use garden feeders.

During breeding, the young receive softened plant food along with some insects and other small invertebrates. Outside the breeding season the birds often feed socially in flocks, moving between seed-rich patches and feeding stations.

Much of the population is resident or makes only short-distance movements, but birds from northern Europe are more migratory. Winter flocks can therefore contain both local birds and migrants that have moved south or west from colder breeding areas.

Movements are flexible and strongly influenced by food and weather. Even largely resident birds may range more widely outside breeding as natural seed supplies change through autumn and winter.

The female builds a compact cup nest in dense shrubs, hedges, conifers or other trees, using fine twigs, grasses and moss and lining it with softer material. A typical clutch contains 4–5 eggs, incubated by the female for about 14 days while the male often brings food.

Both parents feed the chicks, which usually remain in the nest for about 14–16 days before fledging. Two broods are typical when conditions allow.

European greenfinches have also become established well outside their native range. Birds from Britain were released in New Zealand by acclimatisation societies between 1862 and 1868, and the species is now common across much of the main islands. Introduced populations are also established in southeastern Australia, including Tasmania, and in parts of southern South America such as Argentina.

These populations show how readily the species can adapt to new temperate landscapes once suitable seed-rich feeding habitat and nesting cover are available.

European greenfinches have been hit particularly hard by finch trichomonosis, a potentially fatal disease caused by the protozoan parasite Trichomonas gallinae. The parasite attacks tissues in the mouth, throat and upper digestive tract, producing inflammation and lesions that make swallowing progressively more difficult. Severely affected birds may sit fluffed up, drop food from the bill and eventually die because they can no longer eat or drink normally.

A study published in 2010 documented the rapid collapse in British greenfinch numbers after a major epidemic emerged around 2005. The same highly pathogenic parasite lineage subsequently appeared in other parts of Europe. Research in the Netherlands published in 2019 found that infected greenfinches could develop severe internal disease even when obvious external lesions were absent, so infection may be more widespread than visible sick birds alone suggest.

Transmission is favoured where many birds repeatedly share contaminated food or water. Feeders, bird tables and drinking stations can therefore become local transmission points unless they are kept clean and food remains dry and fresh.

The European greenfinch is classified as least concern on the IUCN Red List. It remains widespread across Europe, north-west Africa and western Asia.

Despite this global status, breeding numbers across Europe are about 21% lower over the long-term series and about 18% lower in 2015–2024. Finch trichomonosis has caused especially severe losses in parts of northern and western Europe.