Eurasian Jay - Garrulus glandarius Eurasian Jay By Melissa Mayntz With more than 30 recognized subspecies , the exact color patterns and plumage shades of the Eurasian jay can vary considerably in different geographic ranges. This is one of the most colorful corvids and is instantly recognizable because of its distinct markings even in populations with significantly different colors. Common Name: Eurasian Jay, Jay, Common Jay, European Jay, Acorn Jay Scientific Name: Appearance: Bill: Relatively short but thick, black, slightly rounded, framed with rictal bristles Size: 14 inches long with 21-23-inch wingspan , heavy build, long tail, crown feathers can be raised into a short crest Colors: Black, white, blue, tan, pink-brown, gray, rust Markings: Genders are similar but there is much geographic variation in plumage color and especially head markings. Typically, the upperparts range from pinkish-brown to darker tan or rust, with the back showing more pronounced gray or gray-brown. The wings are black with a broad white patch and white edging on the primary feathers , and the scapulars are light blue with fine black barring.

The underparts are paler, and the throat is white or pale buff bordered with a thick black malar stripe . The rump and undertail coverts are white. The crown and face vary most between populations, and could be brown with black streaking on the crown or white with a solid black crown. The forehead may be pale or dark. The tail is solid black and very gently rounded when spread. The legs and feet are pale, and the eyes have a light iris that ranges from yellow to light blue. Juveniles are similar to adults but with generally darker plumage and less defined head markings. continue reading below our video How to Turn Your Hobby into a Small Business Foods: Nuts, fruit, insects, eggs, bird hatchlings, amphibians, small mammals (See: Omnivorous ) Habitat and Migration: These jays prefer thick, deciduous forests, ideally with an abundance of oak and beech trees for nuts, but they are also found in coniferous or mixed forests as well as parks, gardens and backyards with plenty of mature trees.

They are common year-round from the United Kingdom to the Iberian Peninsula and northwestern Africa throughout Europe including southern Scandinavia and parts of the Middle East, east through Russia and as far as China, Japan and northern India. Though Eurasian jays may become nomadic in winter to seek out the best food sources, they generally do not migrate significant distances. Mountain populations may retreat to lower elevations in the winter. Vocalizations: These jays are noisy and can make a variety of squawks and screeches. The most common call is a harsh "aaaack-aaaack" made when alarmed, agitated or in flight, usually with 2-3 repetitions of even length. Some mimic calls, particularly of avian predators such as hawks and owls, are also part of these jays' repertoire. Behavior: These are solitary birds but can be found in pairs during the breeding season and often form small flocks for foraging in the fall and winter. They are shy and will spook easily, but their slow, jerky flight with an undulating path is easy to recognize.

While foraging , Eurasian jays glean insects from foliage or scour the ground for nuts, caching them for winter storage, and those caches help reforest many areas. Reproduction: These are monogamous birds believed to mate for life , though Eurasian jays do not often stay together during the winter and will instead renew pair bonds every spring. A mated pair works together to build a cup-shaped nest of twigs lined with moss, grass, feathers, fur or other soft materials, positioned in a tree 12-20 feet above the ground. The oval-shaped eggs range from whitish-buff to gray-green and are uniformly speckled. There are 4-7 eggs in a brood , but only one brood is raised by a mated pair each year. The female incubates the eggs for 16-19 days, and the altricial chicks are fed by both parents for an additional 21-23 days after hatching. Though they can independently feed themselves, young Eurasian jays often stay near their parents for several months, until they are chased away to find their own territory before the next breeding season begins.

Attracting Eurasian Jays: Despite their shy nature, these jays can be regularly attracted to backyards with mature trees, especially oak or beech trees that serve as a ready, natural food source. Providing fruit-bearing shrubs, preserving leaf litter for foraging and offering peanuts at tray or platform feeders can also tempt Eurasian jays to visit. Conservation: Because of their widespread range and high, stable population numbers, the Eurasian jay is not considered threatened or endangered , though some local subspecies may be facing greater threats. Similar Birds: Study Finds Eurasian Jays Keep Quiet When Hiding Food - The New York Times The New York Times Science |When Hiding Their Food, Eurasian Jays Keep Quiet Search Continue reading the main story The Eurasian jay, a member of the crow family, hides acorns and other food in several thousand locations every year, to be retrieved when food is scarce. But pilfering by other birds is common, so the jays have developed a strategy, a new study reports: they minimize the noise they make while hiding, or “caching,” their food supplies.

In an experiment, the researchers watched jays caching in three different settings: when birds were alone; when the birds could hear a potential pilferer but not see it; and when they were in plain sight of the thief. Photo Credit Kylie Millar When the pilferer could only listen to caching, the jays avoided noisy gravel and instead used sand and quiet locations when hiding their provisions. By contrast, when birds were alone or with a potential pilferer that could see and hear the jay, the birds were not as diligent about staying quiet. “This suggests that these birds have sophisticated cognitive abilities,” said an author of the study, Rachael C. Shaw, a comparative psychologist at the University of Cambridge. “They are very socially aware.” Ms. Shaw, whose findings are in the current issue of The Proceedings of the Royal Society B , also found that potential thieves “would suppress vocalizing” when observing jays caching. Advertisement Continue reading the main story Other crows engage in caching, but this is the first study to show that a member of the crow family vocalizes less when spying on another bird hiding food.

A version of this article appears in print on December 11, 2012, on Page D3 of the New York edition with the headline: When Hiding Their Food, Eurasian Jays Keep Quiet. Order Reprints | Today's Paper | Subscribe Eurasian Jay Eurasian Jay Weight: 150-190 g DESCRIPTION: Eurasian Jay is a beautiful Corvidae easy to identify thanks to the bright blue wing patch. Both adults are similar with pinkish-grey to reddish-brown upperparts. Rump and uppertail coverts are pure white contrasting with black tail. Upperwing shows rufous lesser and median coverts, and bright blue finely barred black primary and outer great coverts. Rest of upperwing shows black to grey-black feathers with white bases or edges, giving a complex wing pattern very conspicuous in flight. Underparts are similar to mantle. Vent and undertail coverts are white. On the head, crown is white streaked black. Forehead, lores, eye’s area, chin and throat are white. We can see a conspicuous black malar stripe. Nape and head sides are similar to upperparts.

The strong bill is blackish, with whitish to buffy rictal bristles. Eyes are bluish-white. Legs and feet are pinkish-brown. The juvenile is similar to adults, but with darker body plumage, greyer bill, more bluish eyes and brighter legs. By the first autumn, the young shows irregular black barring on the blue wing patch. We find 34 recognized races sharing the large European range. They differ mainly in intensity of colours in body plumage, in crown and wing patterns and in size. The subspecies G.g. brandtii is also displayed on this card. This race is present in Siberia and northern Japan. The bird has streaked crown, reddish head, grey mantle and darker eyes than nominate. G.g. brandtii VOICE: SOUNDS BY XENO-CANTO Eurasian Jay’s common call is a loud, raucous screech “skaaak-shraaak” which be often repeated if the bird is threatened. It also gives wide variety of notes often based on mimicry. These notes usually become softer, forming a subdued warbling song. It is able to imitate the Eurasian Buzzard call!

HABITAT: Eurasian Jay frequents all kinds of woodlands and forests, but mainly beech (Fagus), hornbeam (Carpinus) and its preferred oak (Quercus). The birds of the northern parts of the range frequent conifers and birch forests. This species is commonly seen in parks and large gardens and orchards. It may be seen from sea-level up to 4000 metres of elevation according to the range. G.g. brandtii RANGE: Eurasian Jay is mainly resident from W Europe and NW Africa to E Asia and into SE Asia. It is absent in Iceland. The birds from western and southern parts are sedentary, whereas the eastern and northern populations migrate southwards for food during winter. They sometimes travel in flocks. Some of them also perform altitudinal movements. BEHAVIOUR: Eurasian Jay feeds primarily on invertebrates such as caterpillars and beetles during the breeding and nesting seasons. It gleans from foliage in trees. But as other Corvidae , it also takes eggs and nestlings of several bird species. During autumn and winter, it feeds on seeds and berries, chestnuts and acorns.

One jay often caches acorns in winter (up to 3000 a month), by burying each acorn in the leaf litter or beneath low vegetation. It has learnt to know the green shoots of oak produced by the buried acorns. The next summer, it easily finds them and feeds the germinated acorn. It is a prolific planter of oaks! Eurasian Jay is secretive and wary, often heard rather than seen. It remains hidden into the dense foliage, but sometimes we can see it easily in city parks. This bird is usually solitary or in small family groups. Several unmated birds often gather in spring to attract a mate. In late summer and autumn, they form large communal roosts. During aggressive displays, the male erects crown and rump feathers. It is territorial during spring and chases away the yearlings from the home range. Outside the breeding season, parents tolerate their young within the territory. During the threat displays, the male approaches with head held up, bill pointed upwards and sleeked plumage. It may perform bill-snapping too. During the fights, the jays grapple each other with feet and peck with the bill.

The body feathers are erected, and the semi-opened bill is pointed towards the opponent. Other postures have different functions according to the context, and may be used as well in aggressive behaviour as in courtship displays. Courtship feeding by male to female occurs during laying, incubation or brooding of young at nest, and this is important part of food sources for female. Eurasian Jay performs anting, remaining passive while ants run over its body. After anting, the bird often bathes, then shakes itself and preens. FLIGHT: Eurasian Jay usually flies fairly low and between trees. In flight, the white rump is very conspicuous. It performs undulating flight. During migrations or movements in flocks, they climb high and move out with steady wing beats. Both sexes build a well constructed platform of twigs. The cup is fairly deep and lined with softer plant materials. Nest is situated in fork near the centre of the tree or lower crown, concealed by foliage and vegetation, at about 4-6 metres above the ground. Female lays 3-10 eggs and incubates alone during 16-19 days.

Chicks are fed by both parents and fledge 19-23 days after hatching. They depend on parents during 7-8 weeks, before to be chased away from the home range. They can breed at one or two years of age. DIET: Eurasian Jay feeds on insects during the breeding and nesting seasons. It takes eggs and nestlings of several other bird species. In autumn, it feeds on acorns which excess is buried in soil and dug up when needed. The jay opens acorn by holding it with the feet against the perch and then, it levers bits of shell with the bill. PROTECTION / THREATS / STATUS: Eurasian Jay is common or locally abundant. They were heavily persecuted in the last century, but today, populations are increasing throughout the most part of the range and are stable. The species is not threatened at this moment. G.g. brandtii Jay - Garrulus glandarius - Details - Encyclopedia of Life Learn more about this article Eurasian jay plumage is mainly light reddish brown. Their feathers reflect UV light. Their crests, which are frequently raised during communication, are white with black speckles.

Their beaks are black, and black moustache stripes extend downward from the ends of their beaks. Their tails are black dorsally with a white patch around the base. Their wings have bright blue spots with black speckles. These blue areas appear like triangles or a band, though their orientation and size changes when the wings are spread (they enlarge when spread). There are white bands on the wings, visible during flight. The rest of the wings are black, except for a red triangle where the wing attaches to the body. They often carry their wings so the tips are both on one side of the tail. When compared to other corvids, like Corvus and Pica species, Eurasian jays hold their tail rather high. For this reason the tail feathers incur less damage than in the other genera. Unlike other corvids, Eurasian jays have two plumage phases: juvenile and adult. Other corvids can be aged by a sequence of plumages, but ageing is more difficult in Eurasian jays. They lose their juvenile plumage by autumn of the first year, so birds seen in autumn all appear to be adults. Eurasian jay average basal metabolic rate is 4.99 kJ per hour.

Average mass: 170 g. Other Physical Features: endothermic ; homoiothermic; bilateral symmetry Sexual Dimorphism: female larger 2009. "BirdGuides" (On-line). Jay Garrulus glandarius. Accessed January 15, 2009 at . Goodwin, D. 1956. Further observations on the behavior of the jay Garrulus glandarius . IBIS, 98: 186-219. McNab, B. 2009. Ecological factors affect the level and scaling of avian BMR. Comparative Biochemistry and Physiology, Part A, 152: 22-45. Seel, D. 1976. Moult in five species of Corvidae in Britain. IBIS, 118: 491-536. Veiga, J., V. Polo. 2005. Feathers at nests are potential female signals in the spotless starling. Biology Letters, 1: 334-337.

© The Regents of the University of Michigan and its licensors Learn more about this article Eurasian jays prefer dense foliage, with plenty of trees, bushes, and undergrowth. Trees are essential due to their arboreal lifestyles, though they also forage on the ground. High levels of biodiversity are important so they can enjoy varied diets. Eurasian jays store and eat acorns, so oak trees are important features of their habitat. Deciduous oak forests are preferred for foraging, but coniferous forests provide the best nesting places. Eurasian jays do not like open areas and will avoid entering them if possible. They are most vulnerable to predators in open areas. Habitat Regions: temperate ; terrestrial Terrestrial Biomes: forest ; scrub forest Other Habitat Features: suburban ; agricultural ; riparian Goodwin, D. 1951. Some aspects of the behavior of the jay Garrulus glandarius . IBIS, 93: 414-442, 602-625. Hougner, C., J. Golding, T. Soderqvist. 2006. Economic valuation of a seed dispersal service in the Stockholm National Urban Park, Sweden.

Ecological Economics, 59: 364-374. Pons, J., J. Pausas. 2008. Modelling jay ( Garrulus glandarius ) abundance and distribution for oak regeneration assessment in Mediterranean landscapes. Forest Ecology and Management, 256: 578-584. Selva, N., B. Jedrzejewska, W. Jedrzejewski, A. Wajrak. 2005. Factors affecting caracass use by a guild of scavengers in European temperate woodland. Canadian Journal of Zoology, 83: 1590-1601. © The Regents of the University of Michigan and its licensors Learn more about this article Eurasian jays are omnivores and opportunistic, eating pretty much whatever they can find. Acorns represent the largest part of their diet. They crack the shell by biting it and using their beaks to lever the shell pieces open until they can get the meat out. They collect the acorns of Quercus oaks in the autumn and bury them to eat throughout the year.

They rely on stored food the most from May to July, when they are feeding offspring. One bird can hide between 4500 and 11,000 acorns and will use its memory to locate caches up to ten months later. When hiding acorns, they usually hide only one in a spot, but may hide two or three acorns there. The impulse to store acorns for later use is so strong that captive jays without access to a surplus of acorns will store things that look like acorns, including properly shaped stones. Eurasian jays prefer the acorns of Quercus ilex, Quercus suber, and Quercus faginea, but avoid acorns from Quercus coccifera. Preference is probably linked to relative nutritional value. Quercus ilex acorns have the highest fat content and Quercus coccifera acorns have the highest amount of tannins, at least of the four species studied by Pons and Pausas (2007). Eurasian jays prefer bigger acorns over smaller ones. They usually transport one acorn at a time, but they have been observed carrying up to five at once.

Single acorns are carried in the bill. If more than one is carried, the first one or ones are swallowed and carried in the crop while the last, and usually largest, is held in the bill. In addition to acorns, Eurasian jays eat fruit, grains, and nuts. They also take invertebrates, including worms, snails, slugs, and insects. Eggs are not instinctively recognized as food, but once a bird learns to crack it open and eat the insides, it will continue to do so with other eggs it encounters. They will eat small birds, their young, and their eggs. Reed warblers (Acrocephalus scirpaceus) are an example of a common prey species. Eurasian jays eat plenty of carrion. Researchers studying carrion consumers have found jays will visit about half of available carcasses, especially those in the forest. They use their feet to hold food, but not if the food is sticky. They look everywhere they can for food, including in crevices, loose bark, small holes, under leaves, or any other spot a prey item might be hiding. However, they avoid food that is on open ground instead of covered with foliage.

To open something, they insert their beaks and then try to open them. To turn something over, they pull on it with their beaks or put their beaks under the edges and push sideways. Animal Foods: birds; mammals; eggs; carrion ; insects; terrestrial non-insect arthropods; terrestrial worms Plant Foods: seeds, grains, and nuts; fruit Foraging Behavior: stores or caches food Primary Diet: herbivore (Granivore ); omnivore Clayton, N., D. Griffiths, A. Bennett. 1994. Storage of stones by Jays ( Garrulus glandarius ). IBIS, 136: 331-334. Clayton, N., R. Mellor, A. Jackson. 1996. Seasonal patterns of food storing in the Jay Garrulus glandarius . IBIS, 138: 250-255. Davies, N., S. Butchart, T. Burke, N. Chaline, I. Stewart. 2003. Reed warblers guard against cuckoos and cuckoldry.

Animal Behavior, 65: 285-295. Pons, J., J. Pausas. 2007. Not only size matters: Acorn selection by the European jay ( Garrulus glandarius ). Acta Oecologica, 31: 353-360. © The Regents of the University of Michigan and its licensors Learn more about this article Eurasian jays perform many functions which benefit the ecosystems they inhabit. Their alarm calls alert other species, including red squirrels (Sciurus vulgaris), to the presence of predators. They consume carrion, removing potential disease sources and helping in making nutrients available in the ecosystem. One of their most important ecosystem roles is the dispersal of acorns from Quercus trees. Eurasian jays eat most of the acorns they take, but they also bury acorns and forget about them, leading to oak regeneration. Eurasian jay prefer collecting and burying viable acorns over infertile, dead, or damaged acorns, making them excellent dispersal agents.

They preferentially store acorns on the edges of clear spaces, which is the best place for seedlings to get the right amount of light for germination. Oak trees, including Quercus robur and Quercus petrea, are keystone species in their habitats, providing homes and food for many species of animals, plants, fungi, and lichen. About 80% of all insects on the IUCN Red List need oak trees as part of their life cycle. Ecosystem Impact: disperses seeds; creates habitat; biodegradation Mutualist Species: Learn more about this article Eurasian jays are preyed on by many animals, including cats, birds of prey, and small terrestrial predators. Eggs and young are taken by martens (Martes) and cats (Felis). Adults and fledglings are largely taken by birds of prey. Eurasian jays exhibit a variety of responses to predators, depending on the species and the circumstances. When they see a hawk flying above, they freeze, watch it flying, and emit a low moan in alarm. Mobbing is a common defense mechanism, and they use it against nearly all species of predators.

Sometimes a threatened bird will emit the calls of more powerful birds, like tawny owls (Strix aluco), perhaps in an effort to frighten the attacker. Another use of mimicry in predation defense is when Eurasian jays fly out of sight of a threatening bird and then call it using its own species’ call notes. For instance, they have been observed to fly away from their nest in the presence of a carrion crow (Corvus corone, a nest predator) and mimic the crow’s own calls. Eurasian jays sitting on a nest can also sit quietly or sneak away rather than draw attention to their nest. A valuable defense measure is to simply avoid open spaces, where they are more vulnerable to avian predators. Known Predators: Learn more about this article Eurasian jays use a variety of visual displays to communicate. Displays involve changing body positions, raising feathers on certain parts of their bodies, and movements when necessary. Each display can be given in intense versions or simpler versions. For example, a very submissive bird will extend her wings completely during display, while a less submissive bird will only extend them partway.

The displays are undoubtedly more colorful to the bird than to a human observer because their feathers reflect UV light, which we cannot see. Displays are accompanied by vocalizations in some cases, like when the bird is expressing friendliness or alarm. Males and females have different sexual displays, both of which involve spreading their wings, lifting their feathers, and making a call. The female’s sexual display is similar to the submissive display. The submissive display can be used in a variety of settings, from admitting defeat in a fight to reacting to a human owner, if the bird is tame. They use an aggressive posture to threaten enemies. Jerky alarm movements are performed in silence when the bird does not feel too threatened, serious threats are signaled with the same movements accompanied by alarm screeches. Anxiety is expressed by exaggerated bill wiping and anger is expressed by overzealous feeding movements which only involve actual swallowing if the anger is vented on something edible. Eurasian jays possess a range of jay-specific calls. One of these, the “appeal note,” is used by birds of all ages when they want something.

In young birds, the call is directed to the parents as a request for food, but adults have been heard to utter the same notes while foraging on their own, as if talking to themselves. They use alarm calls to signal the presence of predators. The alarm call is a loud screech emitted once or twice. They also vocalize to express anger, playfulness, affection, warnings about predators, and a myriad of other emotions, intentions, or observations. Eurasian jays are accomplished mimics and will sing songs composed of all sorts of sounds they have heard. They may mimic crying babies, passerine songs, water dropping from a tap, lawn mowers, and even the alarm calls of their predators. Goodwin (1951) supposes they repeat sounds according to the emotional state they experienced when they originally heard the sound. Thus, when threatened or mobbing they copy alarm notes from blackbirds, magpies, and tawny owls, but at more relaxed times may emulate woodpeckers, sparrows, and human whistling. Young birds spend a great deal of time practicing their mimicry until they can perfectly replicate the original sound.

Communication Channels: visual ; tactile ; acoustic Other Communication Modes: mimicry Perception Channels: visual ; ultraviolet; tactile ; acoustic ; chemical Randler, C. 2006. Red Squirrels ( Sciurus vulgaris ) Respond to Alarm Calls of Eurasian Jays ( Garrulus glandarius ). Ethology, 112: 411-416. © The Regents of the University of Michigan and its licensors Learn more about this article Eurasian jays are monogamous and breed once a year in the spring. At the beginning of spring, usually in March and April, unpaired birds spontaneously form gatherings where they choose their mates. In these gatherings, birds pair up and display to each other. They use a wide range of vocalizations, one of which is named the “flight appeal” and is an invitation to fly. Males display more than females and they also chase them. Mating gatherings appear random and may be started by already paired birds chasing and displaying to each other, which excites nearby unpaired birds and encourages them to join in. The gatherings may be as small as three or four birds, but are often as large as thirty or more.

These gatherings also sometimes happen later in the season, like in June, though those gatherings are most likely the result of a paired bird losing its mate or nest rather than new birds finding their first mates. Males offer their mates food as part of courtship. He crushes or tears portions off a food source and offers it to her. If she acts too nervous to accept, he may try approaching her from below, as this is a less threatening way to approach a jay. The birds may call affectionately to each other and engage in a tug-of-war during the ritual. If the female brings the food to her mate, they may pass the food back and forth until one or the other eats it. The ritual appears to strengthen their bond. Later, when the female is busy with the nest, the male will continue to supply her with food. Mating System: monogamous Both parents build and line the nest. Their nests are cup shaped and built in bushes or trees. They are constructed of sticks, freshly broken off of branches, and lined with fine roots, hairs, and the birds’ own feathers.

Egg-laying commences around the end of March, and usually only one brood is raised per season, 4 to 5 eggs are laid, each weighing about 8.5 grams, 6% of which is the shell’s weight. Both parents incubate. The young hatch in 18 days and are naked and blind. They fledge and first leave the nest when they are 20 to 23 days old, but they remain dependent on their parents. The parents begin to wean them when they are around 40 days old, and they are independent around two months of age, though they continue to rob food from their parents for a few days. Eurasian jays reach breeding age at 2 years. Breeding interval: Eurasian jays breed once a year. Breeding season: Eurasian jays breed from March through June. Range eggs per season: 4 to 5. Average time to hatching: 18 days. Range fledging age: 20 to 23 days. Average time to independence: 2 months. Average age at sexual or reproductive maturity (female): 2 years. Average age at sexual or reproductive maturity (male): 2 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous Sometimes only the females incubates, though in many pairs it is both parents. Incubating females clean the nest of parasites by eating them. This behavior seems to be caused by a need to eat anything she finds in the nest that isn’t an egg, lining, or young. Sometimes her need to clean the nest can be exaggerated if she is stressed by the presence of a predator or other stimulus, and she may eat her eggs or young. When a predator approaches, the incubating bird will react according to the situation. If the intruder is far away and may not have noticed the bird, the parent will simply sneak away from the nest or fly off altogether, sometimes making alarm cries as he or she leaves. If the predator approaches, the parent will crouch lower in the nest, facing the threat, with her bill open. An even closer predator will warrant a defensive threat posture, which involves spreading the wings and crouching down.

If the parent decides the only course of action is to attack, she will fly at the predator, attacking it with her claws and beak and crying out using any number of alarm calls, either her own jay calls, the predator’s own calls, or the alarm calls of an entirely different animal. Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Male, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female); pre-independence (Provisioning: Male, Female, Protecting: Male, Female) Goodwin, D. 1951. Some aspects of the behavior of the jay Garrulus glandarius . IBIS, 93: 414-442, 602-625. Goodwin, D. 1956. Further observations on the behavior of the jay Garrulus glandarius . IBIS, 98: 186-219. Robinson, R. 2005.

"BirdFacts: profiles of birds occurring in Britain & Ireland" (On-line). Jay Garrulus glandarius [Linnaeus, 1758]. Accessed January 09, 2009 at . Tutt, H. 1952. The behavior of the jay Garrulus glandarius . IBIS, 94: 162-163. © The Regents of the University of Michigan and its licensors Contributor/s Justification This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations).

The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern. History BBC Nature - Clever Eurasian jays plan for the future Clever Eurasian jays plan for the future By Victoria Gill Science reporter, BBC Nature Jays are members of the corvid family, which is known for its intelligence 'Deceptive' scrub jays hide food Watch Experiments with Eurasian jays have shown that the birds store food that they will want in the future - "planning" for their impending needs. The study revealed that birds would stash more of the foods that they knew would be unavailable to them on forthcoming foraging trips. Jays are not the first birds to show that they might have the capacity for what is known as "mental time travel". But previous claims that birds "plan" in this way have been controversial.

Continue reading the main story Jays are members of the corvid family A favourite food for these colourful birds is acorns, which they cache throughout autumn and unearth during the winter A single bird can bury several thousand acorns each year, so jays play a crucial role in the spread of oak woodlands Jay videos, news and facts To find out if the jays thought about the future, the scientists exploited the birds' habit of hiding or "caching" food for later. In previous studies on Eurasian jays' distant relatives, scrub jays, Prof Nicola Clayton from the University of Cambridge showed that when the birds were offered so much of one food that they became sick of it, they would still store it away in their cache. She and her team interpreted this to mean that the birds knew they would want that food in the future. "The difficulty though, is that we don't know what they know, we only know what they're doing," explained Lucy Cheke, a researcher who works with Prof Clayton and who carried out this latest experiment. The scrub jays, Ms Cheke explained, might just have worked out which foods stored well and which did not.

With their new experiment, the scientists wanted to eliminate the possibility that the birds were using this simple rule. To do this, the researchers put four adult jays through their intellectual paces in a complicated four-day test. 'Sick of peanuts' Lucy Cheke is working with Eurasian jays to find out more about their remarkable cognitive abilities On day one, the jays were presented with two differently coloured boxes in which to hide food. They could gather this from from a mixed pile of peanuts and raisins. The following day, the scientists fed the birds only with raisins, then offered them just one of their boxes. On day three, the birds were given a pile of peanuts before being presented with the other box. "The day after that, they came to cache again," explained Ms Cheke, "and just before they cache, they're fed a big pile of peanuts. "So when they come to cache, they're sick of peanuts. But instead of ignoring the peanuts and only stashing the raisins, the birds appeared to plan ahead. They stored raisins in the tray they were offered after their "peanut binge" and peanuts in the one they were offered after being fed raisins.

"Imagine a child is packing two lunch boxes - one for this afternoon and one for tomorrow," Ms Cheke explained. "If this afternoon they know they'll get to eat loads of cake before their lunch, they'll know only to pack sandwiches in that lunch box." The Cambridge team and their colleagues who work with corvids are continuing to reveal remarkable insights into their intelligence. Ms Cheke is currently investigating Eurasian jays' social abilities - finding out if the birds are able to understand how other birds are feeling. Follow the ants Other researchers based in the same Cambridge laboratory have found examples of what they think is mental time travel in wild birds. Species such as the cocoa woodcreeper follow ant raids to feed on escaping insects Some bird species in Costa Rica follow army ant swarms through the forest, indulging in an insect feeding frenzy as flying insects flee the ant raid. Researcher Corina Logan has observed birds checking ant bivouacs - the temporary nest structures that the ants construct at the end of their raid. She and her colleagues proposed, in a paper in the journal Behavioural Ecology , that the birds might return to the nest sites the following day, in order to follow the next ant raid.

Ms Logan told BBC Nature: "I think [this behaviour] could possibly involve future planning. "The birds were checking bivouacs when they were not hungry, a behaviour that does not make sense until the next morning." Ms Logan says that studying animals in the wild like this helps researchers make sense of their cognitive abilities "in the context of their social and ecological environment". Follow @BBCNature on Twitter 06 MAY 2009, SCI/TECH Related Internet links ADW: Garrulus glandarius: INFORMATION References Geographic Range Garrulus glandarius is widely distributed throughout Europe and Asia. It is a mostly temperate species that lives in forested areas and near human settlements. ( BirdLife International, 2008 ) Biogeographic Regions native Habitat Eurasian jays prefer dense foliage, with plenty of trees, bushes, and undergrowth. Trees are essential due to their arboreal lifestyles, though they also forage on the ground. High levels of biodiversity are important so they can enjoy varied diets. Eurasian jays store and eat acorns, so oak trees are important features of their habitat. Deciduous oak forests are preferred for foraging, but coniferous forests provide the best nesting places.

Eurasian jays do not like open areas and will avoid entering them if possible. They are most vulnerable to predators in open areas. ( Goodwin, 1951 ; Hougner, et al., 2006 ; Pons and Pausas, 2008 ; Selva, et al., 2005 ) Habitat Regions riparian Physical Description Eurasian jay plumage is mainly light reddish brown. Their feathers reflect UV light. Their crests, which are frequently raised during communication, are white with black speckles. Their beaks are black, and black moustache stripes extend downward from the ends of their beaks. Their tails are black dorsally with a white patch around the base. Their wings have bright blue spots with black speckles. These blue areas appear like triangles or a band, though their orientation and size changes when the wings are spread (they enlarge when spread). There are white bands on the wings, visible during flight. The rest of the wings are black, except for a red triangle where the wing attaches to the body. They often carry their wings so the tips are both on one side of the tail.

( "BirdGuides", 2009 ; Goodwin, 1951 ; Goodwin, 1956 ; Veiga and Polo, 2005 ) When compared to other corvids , like Corvus and Pica species, Eurasian jays hold their tail rather high. For this reason the tail feathers incur less damage than in the other genera. Unlike other corvids , Eurasian jays have two plumage phases: juvenile and adult. Other corvids can be aged by a sequence of plumages, but ageing is more difficult in Eurasian jays. They lose their juvenile plumage by autumn of the first year, so birds seen in autumn all appear to be adults. ( Seel, 1976 ) Eurasian jay average basal metabolic rate is 4.99 kJ per hour. ( McNab, 2009 ) Other Physical Features 21.65 in Reproduction Eurasian jays are monogamous and breed once a year in the spring. At the beginning of spring, usually in March and April, unpaired birds spontaneously form gatherings where they choose their mates.

In these gatherings, birds pair up and display to each other. They use a wide range of vocalizations, one of which is named the “flight appeal” and is an invitation to fly. Males display more than females and they also chase them. Mating gatherings appear random and may be started by already paired birds chasing and displaying to each other, which excites nearby unpaired birds and encourages them to join in. The gatherings may be as small as three or four birds, but are often as large as thirty or more. These gatherings also sometimes happen later in the season, like in June, though those gatherings are most likely the result of a paired bird losing its mate or nest rather than new birds finding their first mates. ( Goodwin, 1951 ) Males offer their mates food as part of courtship. He crushes or tears portions off a food source and offers it to her. If she acts too nervous to accept, he may try approaching her from below, as this is a less threatening way to approach a jay. The birds may call affectionately to each other and engage in a tug-of-war during the ritual.

If the female brings the food to her mate, they may pass the food back and forth until one or the other eats it. The ritual appears to strengthen their bond. Later, when the female is busy with the nest, the male will continue to supply her with food. ( Goodwin, 1951 ) Mating System monogamous Both parents build and line the nest. Their nests are cup shaped and built in bushes or trees. They are constructed of sticks, freshly broken off of branches, and lined with fine roots, hairs, and the birds’ own feathers. Egg-laying commences around the end of March, and usually only one brood is raised per season, 4 to 5 eggs are laid, each weighing about 8.5 grams, 6% of which is the shell’s weight. Both parents incubate. The young hatch in 18 days and are naked and blind. They fledge and first leave the nest when they are 20 to 23 days old, but they remain dependent on their parents.

The parents begin to wean them when they are around 40 days old, and they are independent around two months of age, though they continue to rob food from their parents for a few days. Eurasian jays reach breeding age at 2 years. ( Goodwin, 1951 ; Goodwin, 1956 ; Robinson, 2005 ) Key Reproductive Features Average age at sexual or reproductive maturity (male) 2 years Sometimes only the females incubates, though in many pairs it is both parents. Incubating females clean the nest of parasites by eating them. This behavior seems to be caused by a need to eat anything she finds in the nest that isn’t an egg, lining, or young. Sometimes her need to clean the nest can be exaggerated if she is stressed by the presence of a predator or other stimulus, and she may eat her eggs or young. ( Goodwin, 1956 ; Tutt, 1952 ) When a predator approaches, the incubating bird will react according to the situation.

If the intruder is far away and may not have noticed the bird, the parent will simply sneak away from the nest or fly off altogether, sometimes making alarm cries as he or she leaves. If the predator approaches, the parent will crouch lower in the nest, facing the threat, with her bill open. An even closer predator will warrant a defensive threat posture, which involves spreading the wings and crouching down. If the parent decides the only course of action is to attack, she will fly at the predator, attacking it with her claws and beak and crying out using any number of alarm calls, either her own jay calls, the predator’s own calls, or the alarm calls of an entirely different animal. ( Goodwin, 1956 ) Parental Investment The oldest bird recorded in Britain was 16 years, 9 months of age. ( Robinson, 2005 ) Average lifespan 16.75 years Behavior Eurasian jays are primarily arboreal but also forage on the ground. They are sedentary unless acorn crops fail, when they must migrate to other areas for food. Like other corvids , Eurasian jays have complex social behavior.

They exhibit play behaviors, mostly chases that resemble their fleeing response to hawks ( Accipitridae ). ( "BirdGuides", 2009 ; Goodwin, 1951 ) Dominance between jays is not always determined by strength, and hierarchies are not stable. Males are usually dominant over females, but in certain circumstances, like when a male is moulting or his mate is persistent, the female may be dominant. Dominance struggles may be settled with actual tussles, with birds grappling and pulling out each other’s feathers, but they may also be settled without fighting. In dominance contests that don't involve fighting, the outcome of the contest seems to rely on psychological factors which are not fully understood. Overall, jays are not particularly pugnacious toward conspecifics. ( Goodwin, 1951 ) Eurasian jays perform "anting" when ants of the appropriate species, like wood ants ( Formica rufa ), are available. A jay will jump down onto the mass of ants and rub its body, tail, and wings against the ground so that the ants are soon crawling all over the bird’s body.

The jay will shudder and sit upright, often with its tail under its body and between its legs. They probably do not eat the ants which crawl on them. They prefer to ant no more frequently than every other day, possibly two days in a row on occasion. They will bathe in water several times a day. ( Goodwin, 1951 ) Key Behaviors dominance hierarchies Home Range Home range sizes in Eurasian jays vary with season and habitat type. Home ranges in winter and spring were smaller than home ranges in summer and fall. Larger home ranges are found in areas with higher habitat heterogeneity. Home ranges overlap substantially among individuals. ( Rolando, 1998 ) Communication and Perception Eurasian jays use a variety of visual displays to communicate. Displays involve changing body positions, raising feathers on certain parts of their bodies, and movements when necessary. Each display can be given in intense versions or simpler versions. For example, a very submissive bird will extend her wings completely during display, while a less submissive bird will only extend them partway. The displays are undoubtedly more colorful to the bird than to a human observer because their feathers reflect UV light, which we cannot see.

Displays are accompanied by vocalizations in some cases, like when the bird is expressing friendliness or alarm. ( Goodwin, 1951 ; Veiga and Polo, 2005 ) Males and females have different sexual displays, both of which involve spreading their wings, lifting their feathers, and making a call. The female’s sexual display is similar to the submissive display. The submissive display can be used in a variety of settings, from admitting defeat in a fight to reacting to a human owner, if the bird is tame. They use an aggressive posture to threaten enemies. Jerky alarm movements are performed in silence when the bird does not feel too threatened, serious threats are signaled with the same movements accompanied by alarm screeches. Anxiety is expressed by exaggerated bill wiping and anger is expressed by overzealous feeding movements which only involve actual swallowing if the anger is vented on something edible. ( Goodwin, 1951 ) Eurasian jays possess a range of jay-specific calls. One of these, the “appeal note,” is used by birds of all ages when they want something.

In young birds, the call is directed to the parents as a request for food, but adults have been heard to utter the same notes while foraging on their own, as if talking to themselves. They use alarm calls to signal the presence of predators. The alarm call is a loud screech emitted once or twice. They also vocalize to express anger, playfulness, affection, warnings about predators, and a myriad of other emotions, intentions, or observations. ( Goodwin, 1951 ; Randler, 2006 ) Eurasian jays are accomplished mimics and will sing songs composed of all sorts of sounds they have heard. They may mimic crying babies, passerine songs, water dropping from a tap, lawn mowers, and even the alarm calls of their predators. Goodwin (1951) supposes they repeat sounds according to the emotional state they experienced when they originally heard the sound. Thus, when threatened or mobbing they copy alarm notes from blackbirds, magpies, and tawny owls, but at more relaxed times may emulate woodpeckers, sparrows, and human whistling.

Young birds spend a great deal of time practicing their mimicry until they can perfectly replicate the original sound. ( Goodwin, 1951 ) Communication Channels chemical Food Habits Eurasian jays are omnivores and opportunistic, eating pretty much whatever they can find. Acorns represent the largest part of their diet. They crack the shell by biting it and using their beaks to lever the shell pieces open until they can get the meat out. They collect the acorns of Quercus oaks in the autumn and bury them to eat throughout the year. They rely on stored food the most from May to July, when they are feeding offspring. One bird can hide between 4500 and 11,000 acorns and will use its memory to locate caches up to ten months later. When hiding acorns, they usually hide only one in a spot, but may hide two or three acorns there. The impulse to store acorns for later use is so strong that captive jays without access to a surplus of acorns will store things that look like acorns, including properly shaped stones.

( Clayton, et al., 1994 ; Goodwin, 1951 ; Hougner, et al., 2006 ; Pons and Pausas, 2008 ) Eurasian jays prefer the acorns of Quercus ilex, Quercus suber, and Quercus faginea, but avoid acorns from Quercus coccifera. Preference is probably linked to relative nutritional value. Quercus ilex acorns have the highest fat content and Quercus coccifera acorns have the highest amount of tannins, at least of the four species studied by Pons and Pausas (2007). Eurasian jays prefer bigger acorns over smaller ones. They usually transport one acorn at a time, but they have been observed carrying up to five at once. Single acorns are carried in the bill. If more than one is carried, the first one or ones are swallowed and carried in the crop while the last, and usually largest, is held in the bill.

( Pons and Pausas, 2007 ) In addition to acorns, Eurasian jays eat fruit, grains, and nuts. They also take invertebrates, including worms, snails, slugs, and insects. Eggs are not instinctively recognized as food, but once a bird learns to crack it open and eat the insides, it will continue to do so with other eggs it encounters. They will eat small birds, their young, and their eggs. Reed warblers ( Acrocephalus scirpaceus ) are an example of a common prey species. Eurasian jays eat plenty of carrion. Researchers studying carrion consumers have found jays will visit about half of available carcasses, especially those in the forest. They use their feet to hold food, but not if the food is sticky. They look everywhere they can for food, including in crevices, loose bark, small holes, under leaves, or any other spot a prey item might be hiding. However, they avoid food that is on open ground instead of covered with foliage. To open something, they insert their beaks and then try to open them.

To turn something over, they pull on it with their beaks or put their beaks under the edges and push sideways. ( Clayton, et al., 1996 ; Davies, et al., 2003 ; Goodwin, 1951 ; Selva, et al., 2005 ) Primary Diet stores or caches food Predation Eurasian jays are preyed on by many animals, including cats, birds of prey, and small terrestrial predators. Eggs and young are taken by martens ( Martes ) and cats ( Felis ). Adults and fledglings are largely taken by birds of prey. ( Palma, et al., 2006 ; Toyne, 1998 ; Tutt, 1952 ) Eurasian jays exhibit a variety of responses to predators, depending on the species and the circumstances. When they see a hawk flying above, they freeze, watch it flying, and emit a low moan in alarm. Mobbing is a common defense mechanism, and they use it against nearly all species of predators.

Sometimes a threatened bird will emit the calls of more powerful birds, like tawny owls ( Strix aluco ), perhaps in an effort to frighten the attacker. Another use of mimicry in predation defense is when Eurasian jays fly out of sight of a threatening bird and then call it using its own species’ call notes. For instance, they have been observed to fly away from their nest in the presence of a carrion crow ( Corvus corone , a nest predator) and mimic the crow’s own calls. Eurasian jays sitting on a nest can also sit quietly or sneak away rather than draw attention to their nest. A valuable defense measure is to simply avoid open spaces, where they are more vulnerable to avian predators. ( Goodwin, 1951 ; Randler, 2006 ) Anti-predator Adaptations other crows ( Corvus ) Ecosystem Roles Eurasian jays perform many functions which benefit the ecosystems they inhabit. Their alarm calls alert other species, including red squirrels ( Sciurus vulgaris ), to the presence of predators. They consume carrion, removing potential disease sources and helping in making nutrients available in the ecosystem.

( Randler, 2006 ; Selva, et al., 2005 ) One of their most important ecosystem roles is the dispersal of acorns from Quercus trees. Eurasian jays eat most of the acorns they take, but they also bury acorns and forget about them, leading to oak regeneration. Eurasian jay prefer collecting and burying viable acorns over infertile, dead, or damaged acorns, making them excellent dispersal agents. They preferentially store acorns on the edges of clear spaces, which is the best place for seedlings to get the right amount of light for germination. Oak trees, including Quercus robur and Quercus petrea, are keystone species in their habitats, providing homes and food for many species of animals, plants, fungi, and lichen. About 80% of all insects on the IUCN Red List need oak trees as part of their life cycle.

( Hougner, et al., 2006 ; Pons and Pausas, 2008 ) Ecosystem Impact Portuguese oaks (Quercus faginea) Economic Importance for Humans: Positive Eurasian jays are important in the regeneration of oak forests through acorn dispersal. Oaks are important to people because of their wood, beauty, and ability to enhance biodiversity. One study from a park in Sweden estimated how much money it would cost for humans to do the same job as Eurasian jays. The researchers determined it would cost between 1 and 6 million kroners (about 125,000 to 751,000 U.S. dollars) to replace Eurasian jays with people planting acorns in the 2700 hectare park. ( Hougner, et al., 2006 ) A study in Germany found oaks regenerated in pine forests at a rate of 2,000 to 4,000 trees per hectare. Since mother oak trees were largely unavailable, they attributed this regeneration to Eurasian jays.

The area was clearcut about 30 years before the study was performed and mostly pines regenerated. Oak trees were not recruited into the regenerating forest until Eurasian jays moved into the pine forest and began caching acorns. ( Mosandl and Kleinert, 1998 ) Economic Importance for Humans: Negative There are no known adverse effects of Eurasian jays on humans. Conservation Status Eurasian jays have an extensive range, populations are estimated in the millions of individuals, and there are no detected declining population trends. As a result, the IUCN Red List has determined they are "Least Concern." ( BirdLife International, 2008 ) References 2009. "BirdGuides" (On-line). Jay Garrulus glandarius. Accessed January 15, 2009 at . BirdLife International, 2008. "2008 IUCN Red List of Threatened Species" (On-line). Garrulus glandarius. Accessed January 09, 2009 at . Clayton, N., D. Griffiths, A. Bennett. 1994.

Storage of stones by Jays (Garrulus glandarius). IBIS, 136: 331-334. Clayton, N., R. Mellor, A. Jackson. 1996. Seasonal patterns of food storing in the Jay Garrulus glandarius . IBIS, 138: 250-255. Davies, N., S. Butchart, T. Burke, N. Chaline, I. Stewart. 2003. Reed warblers guard against cuckoos and cuckoldry. Animal Behavior, 65: 285-295. Goodwin, D. 1956. Further observations on the behavior of the jay Garrulus glandarius . IBIS, 98: 186-219. Goodwin, D. 1951. Some aspects of the behavior of the jay Garrulus glandarius . IBIS, 93: 414-442, 602-625. Hougner, C., J. Golding, T. Soderqvist. 2006.

Economic valuation of a seed dispersal service in the Stockholm National Urban Park, Sweden. Ecological Economics, 59: 364-374. McNab, B. 2009. Ecological factors affect the level and scaling of avian BMR. Comparative Biochemistry and Physiology, Part A, 152: 22-45. Mosandl, R., A. Kleinert. 1998. Development of oaks (Quercus petraea (Matt.) Liebl.) emerged from bird-dispersed seeds under old-growth pine (Pinus silvetris L.) stands. Forest Ecology and Management, 106: 35-44. Palma, L., P. Beja, M. Pais, L. Cancela da Fonseca. 2006. Why do raptors take domestic prey? The case of Bonelli's eagles and pigeons. Journal of Applied Ecology, 43: 1075-1086. Pons, J., J. Pausas. 2008.

Modelling jay (Garrulus glandarius) abundance and distribution for oak regeneration assessment in Mediterranean landscapes. Forest Ecology and Management, 256: 578-584. Pons, J., J. Pausas. 2007. Not only size matters: Acorn selection by the European jay (Garrulus glandarius). Acta Oecologica, 31: 353-360. Randler, C. 2006. Red Squirrels ( Sciurus vulgaris ) Respond to Alarm Calls of Eurasian Jays (Garrulus glandarius). Ethology, 112: 411-416. Robinson, R. 2005. "BirdFacts: profiles of birds occurring in Britain & Ireland" (On-line). Jay Garrulus glandarius [Linnaeus, 1758]. Accessed January 09, 2009 at . Rolando, A. 1998. Factors affecting movements and home ranges in the jay (Garrulus glandarius).. Journal of Zoology, 246: 249-257.

Seel, D. 1976. Moult in five species of Corvidae in Britain. IBIS, 118: 491-536. Selva, N., B. Jedrzejewska, W. Jedrzejewski, A. Wajrak. 2005. Factors affecting caracass use by a guild of scavengers in European temperate woodland. Canadian Journal of Zoology, 83: 1590-1601. Toyne, E. 1998. Breeding season diet of the Goshawk Accipiter gentilis in Wales. IBIS, 140: 569-579. Tutt, H. 1952. The behavior of the jay Garrulus glandarius . IBIS, 94: 162-163. Veiga, J., V. Polo. 2005. Feathers at nests are potential female signals in the spotless starling. Biology Letters, 1: 334-337.

Question: What is the main food of the Eurasian jay
Answer: Acorns