The Eurasian jay (Garrulus glandarius) is a member of the crow family, Corvidae. It occurs across northern Europe and Asia, being absent only from treeless areas, such as the tundra, and from the driest deserts. Jays are generally found in woodlands, but often feed in open country or even urban areas. The name “jay” derives from Old French gai (modern French: geai), Latin gaius.
The Eurasian jay is a plump bird with a long tail and strong legs. It is 20–28 cm (8-11 inches) long with a 34–42 cm (13-17 inch) wingspan. The body mass can vary from 70 to 100 g (2 1/3 – 3 1/2 oz). In western Siberia birds are larger on average than in the south of the range; males weigh 89–98 g (3 1/4 – 3 1/2 oz), females 80–91 g (2 3/4 – 3 1/4 oz). southern races are much smaller; males 74–86 g (2 2/5 – 3 oz), females 67–79 grams(2 2/5 – 2 4 / 5 ounces). Among standard measurements, the wing chord measures 9.7 to 11.9 cm(3 7 / 8 to 4 6 / 8 inches), the tail measures 10 to 12 cm(4-4 3 / 4 inches) and the tarsus is 2 to 2.6cm( 0 4 / 5to1inch). There are two subspecies recognized currently: Glandarius glandarius which inhabits most of Europe eastwards through Siberia to Kamchatka Peninsula and Sakhalin Island while Glandarius silviae breeds further west including Scandinavia and Iceland down into France where it overlaps with glandarius at its eastern margin . However some authorities consider all Birds West Of The Ural mountains To Be silviae While Others Include Only Those From Britain And Ireland In This Race . Hybridization also complicates matters With Birds Showing A Mix Of Characters Occurring In Germany Austria And Slovenia Where The Two Subspecies Overlap
The adult has pale grey upperparts streaked with blackish brown, while underparts are off-white shading into buff on the flanks; there is considerable variation in plumage tone between individuals however . Juveniles have browner upperparts , lack streaks on their crowns , napes And breasts , have mottled underparts First winters resemble adults but have less developed head streaks Second winter plumage Is similar To that Of first years But more detailed Males take two years to reach full adult plumage Females achieve this after just one year although they may continue molting until they are three years old Molting takes place once yearly usually beginning in late July continuing through till December though sometimes not completed until February During this time They temporarily lose Their head streaks before redeveloping them again by March April when They Also regain Any other feathers lost Eurasian jays molt Into their breeding plumage starting around march continuing into may though some Individuals May Still be shedding feathers As Late As June Breeding plumage Is similar To non breeding Plumage But More Vivid With Stronger Contrasts On both Upperparts And Underparts The throat patch becomes whiter while blue on breast increases In intensity After Mating Which occures From late April Till early June Females Lay Between Three And Eight Eggs hatching Around mid May Both Parentsfeed chicks Which fledge 2531 days later Adults eat mostly invertebrates especially caterpillars beetles spiders earthworms millipedes slugs snails True Bugs larvae centipedes wasps crickets earwigs ants mantids grasshoppers flies termites etc but will also take small mammals reptiles amphibians carrion fruits berries seeds nuts acorns pine cones etc Though Mostly Arboreal When Foraging Jay Spend Much Time On Ground Particularly When Searching For Food Under Snow Or Leaves Jays Have Been Observed Using Tools Such As Small Sticks To Impale Caterpillars Or Digging Into Sandbanks With Their Beaks To Unearth Beetles One Bird Was Even Seen Fashioning A Tool By Biting Notches Into A Birch twig so That It Could Hook Insects Out Of Narrow Cracks Another Used Its Bill Like A Tweezers Plucking Seeds From Dandelions Despite Often Being Described As Cautious Jays Can Appear Bold When Approached Directly Especially If Food Is Present Often Stooping Down To Pick Up Items Right Next To Humans Although Susceptible To Many diseases Including Salmonella Toxoplasmosis Trichomoniasis Chlamydophila Psittaci Mycoplasma Gallisepticum Fowlpox Newcastle Disease Infectious Bronchitis Avian Influenza Encephalomyocarditis Hepatitis Herpes Virus Etc No Particular Pathogen Has Been Linked ConclusivelyTo Large Scale Mortality events Involving These Birds However Climate Change May Pose A Serious Threat In Future With Warming Winters Causing Increased Infestation By parasitic Mites Ixodes Ticovirus Lyme disease Etc While Hotter Summers Raise Levels Of Bacterial Growth LeadingTo Gastroenteritis Coli Enteritis Clostridium Perfringens Salmonellosis Necrotic Enteritis ErysipelasBotulism Etc Aside from these natural threats humans pose perhaps an even greater one Through Habitat destruction Deforestation fragmentation Intensification Pesticide Use Pollution Hunting Trapping Egg Collecting All nestlings Are Taken For FoodBy Some Cultures Fortunately Though Jay Numbers Remain Healthy Overall ThanksPartlyTo Ongoing Reforestation Efforts Across Europe