Eurasian jay

TheEurasian jay(Garrulus glandarius) is a species ofpasserinebird in the crow familyCorvidae. It has pinkish brown plumage with a black stripe on each side of a whitish throat, a bright blue panel on the upper wing and a black tail. The Eurasian jay is a woodland bird that occurs over a vast region from western Europe and north-west Africa to theIndian subcontinentand further to the eastern seaboard of Asia and down into south-east Asia. Across this vastrange, several distinct racial forms have evolved which look different from each other, especially when comparing forms at the extremes of its range.
The bird is calledjay, without anyepithets, by English speakers inGreat BritainandIreland.
The Eurasian jay wasformally describedby the Swedish naturalistCarl Linnaeusin 1758 in thetenth editionof hisSystema Naturaeunder thebinomial nameCorvus glandarius.Linnaeus specified thelocalityas "Europa" but this was restricted to Sweden byErnst Hartertin 1903.The Eurasian jay is now one of three species placed in the genusGarrulusthat was established in 1760 by the French zoologistMathurin Jacques Brisson.The genus nameGarrulusis aLatinword meaning "chattering", "babbling" or "noisy". The specific epithetglandariusisLatinmeaning "of acorns".
Eight racial groups (33subspeciesin total) were recognised bySteve Madge&Hilary Burnin 1994:
TheInternational Union for Conservation of Nature(IUCN) andBirdlife Internationalsplit the Eurasian jay into three species. The subspeciesG. g. leucotisbecomes the white-face jay (Garrulus leucotis)and thebispecularisgroup containing six subspecies becomes the plain-crowned jay (Garrulus bispecularis).
The Eurasian jay is a relatively smallcorvid, similar in size to awestern jackdaw(Coloeus monedula) with a length of 34–35 cm (13–14 in) and a wingspan of 52–58 cm (20–23 in).The nominate race has light rufous brown to a pinkish brown body plumage. The whitish throat is bordered on each side by a prominent black moustache stripe. The forehead and crown are whitish with black stripes. The rump is white. The complex colouring on the upper surface of the wing includes black and white bars and a prominent bright blue patch with fine black bars. The tail is mainly black.
The most characteristic call is a harsh, rasping screech that is used upon sighting various predators and as an advertising call. The jay is well known for itsmimicry, often sounding so like a different species that it is difficult to distinguish its true identity unless the bird is seen. It will imitate the calls of birds of prey such as the mew of thecommon buzzardand the cackle of thenorthern goshawk.
A member of the widespreadjaygroup, it inhabits mixedwoodland, particularly withoaks, and is a habitualacornhoarder. In recent years, the bird has begun to migrate into urban areas, possibly as a result of continued erosion of its woodland habitat. Before humans began planting the trees commercially on a wide scale, Eurasian jays were the main source of movement and propagation for theEuropean oak(Q. robur), each bird having the ability to spread more than a thousand acorns each year. Eurasian jays will also bury the acorns of other oak species, and have been cited by theNational Trustas a major propagator of the largest population ofholm oak(Q. ilex) in Northern Europe, situated inVentnoron theIsle of Wight.Jays have been recorded carrying single acorns as far as 20 km, and are credited with the rapid northward spread of oaks following the last ice age.
Eurasian jays normally first breed when two years of age, although they occasionally breed when only one year. Both sexes build the nest which is usually placed in a fork or on a branch of a tree close to the main trunk at a height of 2–5 m (6 ft 7 in – 16 ft 5 in) above the ground. Very occasionally the nest is located on a building. The nest has a base of twigs 3–15 mm (0.12–0.59 in) in diameter and a lining of thinner twigs, roots, grass, moss and leaves. The eggs are laid daily, normally early in the morning. The clutch is 3–6 eggs which are pale green to pale olive brown and are covered with fine darker speckles. They sometimes have brown or black streaks concentrated at the broader end. The eggs are 31.3 mm × 23.0 mm (1.23 in × 0.91 in) and weigh around 8.5 g (0.30 oz). They are incubated by the female and hatch after 16–19 days. While the female is on the nest the male brings her food. Both parents feed and care for the young which fledge after 19–23 days. The parents continue to feed the fledgelings until they are 6–8 weeks of age. Only a single brood is raised each year.
The maximum recorded age is 16 years and 9 months for a bird inSkelton, York, United Kingdom, that was ringed in 1966 and found dead in 1983.
Feeding in both trees and on the ground, it takes a wide range ofinvertebratesincluding manypestinsects, acorns (oakseeds, which it buries for use during winter),beechand otherseeds,fruitssuch asblackberriesandrowan berries, youngbirdsand eggs, bats, and smallrodents. Like most species, the jay's diet changes with the seasons but is noteworthy for its prolific caching of food—especially oak acorns and beechnuts—for winter and spring. While caching occurs throughout the year, it is most intense in the autumn.
In order to keep its plumage free from parasites, it lies on top of anthills with spread wings and lets its feathers be sprayed withformic acid.
Similar to other corvids, Eurasian jays have been reported to plan for future needs.Male Eurasian jays also take into account the desires of their partner when sharing food with her as a courtship ritualand when protecting food items from thieving conspecifics.