TheEurasian jay (Garrulus glandarius), also known simply as thejay without anyepithets in the United Kingdom and Ireland, is a species ofpasserine bird 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 subcontinent and farther 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.
thebrandtii group (four races inSiberia and northernJapan), with a streaked crown, reddish head, darkiris and grey mantle.
theleucotis group (two races insouth-east Asia), with no white in the wing, a white forecrown, black hindcrown and much white on the sides of the head.
thebispecularis group (six races in theHimalayan region), with an unstreaked rufous crown, and no white wing-patch.
thejaponicus group (four races in the southern Japanese islands), with a large white wing-patch, blackish face and scaled crown.
TheInternational Union for Conservation of Nature (IUCN) andBirdlife International split the Eurasian jay into three species. The subspeciesG. g. leucotis becomes the white-face jay (Garrulus leucotis)[10] and thebispecularis group containing six subspecies becomes the plain-crowned jay (Garrulus bispecularis).[11]
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).[12] 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.[9]
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 buzzard and the cackle of thenorthern goshawk.[13][14]
A member of the widespreadjay group, it inhabits mixedwoodland, particularly withoaks, and is a habitualacorn hoarder. 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 Trust as a major propagator of the largest population ofholm oak (Q. ilex) in Northern Europe, situated inVentnor on theIsle of Wight.[15] 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.[16]
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.[17]
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.[18][19]
Feeding in both trees and on the ground, it takes a wide range ofinvertebrates including manypest insects, acorns (oak seeds, which it buries for use during winter),[20]beech and otherseeds,fruits such asblackberries androwan berries, youngbirds and 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.[21]
Similar to other corvids, Eurasian jays have been reported to plan for future needs.[22] Male Eurasian jays also take into account the desires of their partner when sharing food with her as a courtship ritual[23] and when protecting food items from thieving conspecifics.[24]
^Jobling, James A. (2010).The Helm Dictionary of Scientific Bird Names. London: Christopher Helm. pp. 171,173.ISBN978-1-4081-2501-4.
^abMadge, Steve;Burn, Hilary (1994).Crows and Jays.Helm Identification Guides. pp. 95–97.ISBN978-0-7136-3999-5. (although the text accompanying plate 11 states "some 35 races", the species account on page 95 states that 33 are recognised, and the sum of the numbers of races listed for each group is 33, indicating that the figure accompanying the plate is an error)
^Howe, H.F.; Smallwood, J. (1982). "Ecology of seed dispersal".Annual Review of Ecology and Systematics.13 (1):201–228.doi:10.1146/annurev.es.13.110182.001221.
^Clayton, N.S.; Mellor, R.; Jackson, A. (1996). "Seasonal patterns of food storing in the JayGarrulus glandarius".Ibis.138 (2):250–255.doi:10.1111/j.1474-919X.1996.tb04336.x.
Cramp, Stanley; et al., eds. (1994). "Garrulus glandarius Jay".Handbook of the Birds of Europe the Middle East and North Africa: The Birds of the Western Palearctic. Vol. VIII:Crows to Finches. Oxford: Oxford University Press. pp. 7–31.ISBN978-0-19-854679-5.
Cheke, Lucy G.; Bird, Christopher D.; Clayton, Nicola S. (2011). "Tool-use and instrumental learning in the Eurasian jay (Garrulus glandarius)".Animal Cognition.14 (3):441–455.doi:10.1007/s10071-011-0379-4.PMID21249510.S2CID9123984.
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