The Eurasian jay (Garrulus glandarius) is a species of passerine bird in the crow family Corvidae. It is a woodland bird that occurs over a vast region from western Europe and northwest Africa to the Indian subcontinent and further to the eastern seaboard of Asia and down into southeast Asia. Across this vast range, several distinct racial forms have evolved which look different from each other, especially when comparing forms at the extremes of its range.
The Eurasian jay is a small passerine bird with pinkish brown plumage. The whitish throat is bordered on each side by a prominent black mustache stripe. The forehead and crown are whitish with black stripes. The rump is white. The complex coloring on the upper surface of the wing includes black and white bars and a prominent bright blue patch with fine black bars. The tail of this bird is mainly black.
Eurasian jays can be found from western Europe and northwest Africa to the Indian subcontinent and further to the eastern seaboard of Asia and down into Southeast Asia. These birds inhabit mixed woodland, particularly with oaks, and often frequent parks, orchards, and large gardens. Northern birds can be found in conifers and birch forests.
Eurasian jays are shy secretive birds that are often heard rather than seen. They are generally solitary but may sometimes spend time in small family groups and during cold periods of the year, they gather in large communal roosts. Eurasian jays are active during the day and feed in both trees and on the ground. They often cache their food, especially oak acorns, and beechnuts for winter and spring. Caching usually occurs throughout the year, but it is most intense in the autumn. Their usual call is the alarm call which is a harsh, rasping screech and is used upon sighting various predatory animals. Eurasian jays are also well known for their mimicry, often sounding so like a different species that it is virtually impossible to distinguish their true identity unless jays are seen. They will even imitate the sound of the bird they are attacking, such as a Tawny owl, which they do if attacking during the day.
Eurasian jays are omnivores. They take a wide range of invertebrates including many pest insects, acorns (oak seeds, which it buries for use during winter), beech and other seeds, fruits such as blackberries and rowan berries, young birds and eggs, bats, and small rodents.
Eurasian jays are monogamous and form long-lasting pair bonds. Their breeding season occurs in spring. Pairs nest solitarily in trees or large shrubs laying usually 4-6 eggs that hatch after 16-19 days. The chicks are blind and naked when they hatch and fledge generally after 21-23 days. Both parents typically feed the young for another 7-8 weeks, before they become completely independent. Reproductive maturity is attained at 1-2 years of age.
Eurasian jays are not considered threatened or endangered at present, however, in the past, they were collected for their bright wing feathers and were also heavily persecuted by farmers.
According to the IUCN Red List, the total population size of the Eurasian jay is 33,000,000-65,100,000 mature individuals. In Europe, the breeding population consists of 7,480,000-14,600,000 pairs, which equates to 15,000,000-29,300,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List and its numbers today are stable.
Eurasian jays are habitual acorn hoarders. In recent years, these birds have begun to migrate into urban areas, possibly as a result of the continued erosion of their woodland habitat. Before humans began planting the trees commercially on a wide scale, Eurasian jays were the main source of movement and propagation for the European oak as each bird can spread more than a thousand acorns each year! Eurasian jays also bury the acorns of other oak species and have been cited by the National Trust as a major propagator of the largest population of Holm oak in Northern Europe, situated in Ventnor on the Isle of Wight. Jays are able to carry single acorns as far as 20 km and are credited with the rapid northward spread of oaks following the last ice age.
