Common linnets are slim birds with long tails. Their upper parts are brown, the throat is sullied white and the bill is grey. The summer male has a grey nape, red head patch, and red breast. Females and young birds lack the red and have white underparts; their breasts are streaked buff.
Common linnets breed in Europe, the western Palearctic, and North Africa. Some populations are resident, but many eastern and northern birds migrate farther south in the breeding range or move to the coasts. They are sometimes found several hundred miles off-shore. During the breeding season, Common linnets prefer open land with thick bushes, including heathland, moorlands and hills with scattered trees, light woodlands, open rocky hillsides, mountain slopes, alpine meadows, valleys with low shrubs, and edges of cultivated areas. When not breeding, they can be found in coastal dunes and salt marshes.
Common linnets are diurnal birds. They are usually seen in pairs or small groups but can form large flocks outside the breeding season, sometimes mixed with other finches, such as twite, on coasts, and salt marshes. Common linnets feed on the ground and low down in bushes. The song of these birds is pleasant and contains fast trills and twitters.
Common linnets are herbivores (granivores) and feed mainly on the seeds of various plants. They also eat fruits, and buds and sometimes catch insects and small snails.
Common linnets are serially monogamous and form pairs only for one breeding season. During this time they are very territorial defending their nests and the area around them. Common linnets breed between mid-April and early August and may produce 2 or 3 broods per season. They build cup-shaped nests in bushes and line them with plant down, fur, and feathers. The female lays 4 to 6 eggs and incubates them alone during 11-13 days. The male provides her with food during this period. When chicks hatch, both adults feed and protect them for about 10-14 days. At this time the young fledge but still remain dependant on their parents for 2 weeks more.
The population of the Common linnet declines due to the intensification of agriculture, which causes the destruction of their habitat, especially hedgerows.
According to IUCN Red List, the total population size of the Common linnet is 54,000,000-98,000,000 mature individuals. In Europe, the breeding population consists of 17,600,000-31,900,000 pairs, which equates to 35,100,000-63,700,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List but its numbers today are decreasing.