Grey jay

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Grey jay
Perisoreus canadensis mercier2.jpg
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Corvidae
Genus: Perisoreus
Species: P. canadensis
Binomial name
Perisoreus canadensis
(Linnaeus, 1766)
Subspecies

9 subspecies; see text

Perisoreus canadensis range.png
Grey jay range
Synonyms

Dysornithia brachyrhyncha, Sw.

The grey jay (Perisoreus canadensis), also gray jay, Canada jay or whisky jack, is a passerine bird of the family Corvidae. It is found in boreal forests of North America north to the tree line and in the Rocky Mountains subalpine zone south to New Mexico and Arizona. A fairly large songbird, the grey jay has pale grey underparts, darker grey upperparts, and a grey-white head with a darker grey nape. It is one of three members of the genus Perisoreus along with the Siberian jay (P. infaustus) found from Norway to eastern Russia, and the Sichuan jay (P. internigrans) native to the mountains of eastern Tibet and northwestern Sichuan. The grey jay itself has nine recognized subspecies.

Like all Perisoreus jays, grey jays live year-round on permanent territories in coniferous forests, surviving in winter months on food stored throughout their territory in warmer periods. The birds form monogamous mating pairs, with pairs accompanied on their territories by a third juvenile from the previous season. Grey jays adapt to human activity in their territories and are known to approach humans for food, inspiring a list of colloquial names including lumberjack, camp robber, and venison-hawk.

The grey jay has become associated with the Algonquian and Dene mythological figure Wisakedjak, a benevolent figure whose name was Anglicized to Whiskyjack. In 2016, an online poll and expert panel conducted by Canadian Geographic magazine selected the grey jay as the national bird of Canada, although the designation is not formally recognized.

Taxonomy[edit]

Subspecies P. c. capitalis, Grand Tetons, Wyoming
Subspecies P. c. capitalis (left), and P. c. obscurus (right); illustration by Keulemans, 1877

Carl Linnaeus described the grey jay as Corvus canadensis in the 12th edition of his Systema Naturae in 1766.[2] William John Swainson named it Dysornithia brachyrhncha in 1831.[3] Bonaparte assigned the grey jay to the genus Perisoreus in 1838 in A geographical and comparative list of the birds of Europe and North America, along with the Siberian jay, P. infaustus.[4] The grey jay and its close relatives belong to the crow and jay family Corvidae. However, they are not closely related to other birds known as jays, they are instead related to the genus Cyanopica, which contains the Azure-winged magpie.[5] Its relatives are native to Eurasia, and ancestors of the grey jay are thought to have diverged from their Old World relatives and crossed Beringia into North America.[6]

A 2012 genetic study revealed four clades across its range: a widespread boreal or taiga clade ranging from Alaska to Newfoundland and ranging south to the Black Hills of South Dakota, Wyoming, Utah and New England, a transcascade clade in eastern Washington and Oregon and ranging into Alberta and Montana, a Rocky Mountains (Colorado) clade from the southern Rocky Mountains, and (the earliest offshoot) a Pacific clade from coastal British Columbia, Washington and southwestern Oregon. There was also a population of the boreal clade in the central Rocky Mountains between the Colorado and transcascade clades.[6]

The boreal clade is genetically diverse, suggesting that grey jays retreated to multiple areas of milder climate during previous ice ages and recolonized the region in warmer times.[6]

Nine subspecies are recognized:[7][8]

  • P. c. albescens, also known as the Alberta jay, was described by American ornithologist James L. Peters in 1920. It is a resident from northeastern British Columbia and northwestern Alberta southeastward, east of the Rocky Mountains to South Dakota (Black Hills). It is casual in northwestern Nebraska.[9]
  • P. c. bicolor, described by American zoologist Alden H. Miller in 1933, is a resident in southeastern British Columbia, southwestern Alberta, eastern Washington, northeastern Oregon, northern and central Idaho, and western Montana.[9] Miller noted that the subspecies appeared to be a stable intermediate form between canadensis and capitalis. It was a similar size to subspecies canadensis, and had a wholly white head with a black nape. Its body markings resembled those of capitalis but its coloration resembled candensis.[10]
  • P. c. canadensis breeds from northern British Columbia east to Prince Edward Island, and south to northern Minnesota, northern Wisconsin, northern Michigan, northeastern New York, northern Vermont, northern New Hampshire, and Maine. It winters at lower altitudes within the breeding range and south to southern Ontario and Massachusetts, casually to central Minnesota, southeastern Wisconsin, northwestern Pennsylvania, and central New York. Perisoreus c. canadensis is accidental in northeastern Pennsylvania (Philadelphia).[9]
  • P. c. capitalis is a resident in the southern Rocky Mountains from eastern Idaho, south-central Montana, and western and southern Wyoming south through eastern Utah, and western and central Colorado, to east-central Arizona and north-central New Mexico.[9] American naturalist Spencer Fullerton Baird described this subspecies in 1873. It has a wholly whitish head with a pale nuchal band, and overall more ashy grey plumage.[11] It is also generally larger than subspecies canadensis.[10]
  • P. c. griseus is a resident from southwestern British Columbia and Vancouver Island south through central Washington and central Oregon to the mountains of north-central and northeastern California. It was described by Robert Ridgway in 1899.[9]
  • P. c. nigricapillus, also known as the Labrador jay,[12] is a resident in northern Quebec (Kuujjuaq, Whale River, and George River), throughout Labrador and Nova Scotia, and in southeastern Quebec (Mingan and Blanc-Sablon). It was described by Ridgway in 1882.[9]
  • P. c. obscurus, described by Ridgway in 1874, is a resident in the coastal belt from Washington (Crescent Lake, Seattle, and Columbia River) through western Oregon to northwestern California (Humboldt County).[9] Also known as the Oregon jay,[13] this subspecies has more dark brown than grey upperparts.[11]
  • P. c. pacificus is a resident of central Alaska and northwestern Canada, including the Yukon and along the Mackenzie River. It was described by Johann Friedrich Gmelin in 1788.[8]
  • P. c. sanfordi is found in Newfoundland.[8] Harry C. Oberholser described it in 1914 from a specimen collected by a Dr Sanford, whom he named it after. Oberholser reported that it was smaller and darker than the nominate race P. c. canadensis and more closely resembled P. c. nigricapillus.[14]

Two additional subspecies were formerly recognized:

  • P. c. arcus is a resident in the Rainbow Mountains area, and headwaters of the Dean and Bella Coola Rivers of the central Coast Ranges, British Columbia.[9] Described by Miller in 1950, it is often recognized as P. c. obscurus.[8]
  • P. c. barbouri was described by Allan Brooks in 1920.[9] Abundant on Anticosti Island in eastern Quebec, this subspecies is significantly heavier but not larger than other grey jay subspecies in Quebec, and does not appear to be genetically distinct from P. c. nigricapillus[8] or other populations in Quebec.[15]

Description[edit]

The grey jay is a relatively large songbird, though smaller than other jays. A typical adult grey jay is between 25 to 33 cm (9.8 to 13.0 in) long. Its wingspan is around 45 cm (18 in). It weighs about 65 to 70 g (2.3 to 2.5 oz). Adults have medium grey back feathers with the underside lighter grey. The distinctive head colouring is mostly white with a dark grey or black back and hood, with a short black beak and dark eyes. The long tail is medium grey with lighter tips.[16] The plumage is thick, providing insulation in the bird's cold native habitat.[17] Grey jays are not sexually dimorphic, like most corvids, but males are slightly larger than females. Juveniles are initially coloured very dark grey all over, gaining adult plumage after a first moult in July or August.[18] These birds can live for up to 19 years.[19]

Grey jays use a variety of vocalizations, and like other corvids may mimic other bird species, especially predators. Calls include a whistled quee-oo, and various clicks and chuckles. When predators are spotted, the bird announces a series of harsh clicks to signal a threat on the ground, or a series of repeated whistles to indicate a predator in the air.[17]

Distribution and habitat[edit]

Perisoreus canadensis obscurus in Mount Rainier National Park

The grey jay is a native resident from northern Alaska east to Newfoundland and Labrador and south to northern California, Idaho, Utah, east-central Arizona, north-central New Mexico, central Colorado, and southwestern South Dakota. It is also a native resident in northern Minnesota, northern Wisconsin, northern Michigan, northern New York, and northern New England. The grey jay may wander north of the breeding range. In winter it travels irregularly to northwestern Nebraska, central Minnesota, southeastern Wisconsin, central Michigan, southern Pennsylvania, central New York, Connecticut, and Massachusetts.[9][20]

The vast majority of grey jays live where there is a strong presence of black spruce (Picea mariana), white spruce (P. glauca), Engelmann spruce (P. engelmanni), jack pine (Pinus banksiana), or lodgepole pine (P. contorta). Grey jays do not inhabit the snowy, coniferous, and therefore seemingly appropriate Sierra Nevada of California where no spruce occur. Nor do grey jays live in lower elevations of coastal Alaska or British Columbia dominated by Sitka spruce (Picea sitchensis). The key habitat requirements may be sufficiently cold temperatures to ensure successful storage of perishable food and tree bark with sufficiently pliable scales arranged in a shingle-like configuration that allows grey jays to wedge food items easily up into dry, concealed storage locations. Storage may also be assisted by the antibacterial properties of the bark and foliage of boreal tree species. An exception to this general picture may be the well-marked subspecies P. c. obscurus, once given separate specific status as the 'Oregon jay'. It lives right down to the coast from Washington to northern California in the absence of cold temperatures or the putatively necessary tree species.[20]

Behaviour[edit]

Mating[edit]

Grey jays typically breed at two years of age. Pairs are monogamous and remain together for their lifetime, but a male or female will find another mate following the disappearance or death of their partner.[20] Grey jay pairs breed during March and April, depending on latitude,[20][21][22] in permanent, all-purpose territories.[20][21][22][23] Second broods are not attempted, perhaps allowing greater time for food storage.[20][21]

Grey, sooty plumage of a juvenile

Grey jays cooperatively breed.[22][24][25] During the nest-building phase of the breeding season, grey jay breeding pairs are accompanied by a third, juvenile bird. Approximately 65% of grey jay trios included a dominant juvenile from the pair's previous breeding season, and approximately 30% of trios included non-dominant juveniles who had left their parents' territory. Occasionally, two nonbreeding juveniles accompany a pair of adults. The role of juveniles is in allofeeding, to retrieve caches and bring food to younger siblings;[24][25] however, this is only allowed by the parents during the postfledgling period.[22][24][25] Until then, parents will drive the other birds away from the nest. This may reduce the frequency of predator-attracting visits to the nest when young are most vulnerable. The benefits of juveniles participating in subsequent brood care may include "lightening the load" for the breeding pair, which may possibly increase longevity, reducing the probability of starvation of nestlings, and detecting and mobbing predators near the nest.[24] Dominant juveniles may eventually inherit the natal territory and breed, while unrelated juveniles may eventually fill a vacancy nearby or form a new breeding pair on previously unoccupied ground.[22]

Nesting[edit]

Female incubating her eggs

Breeding grey jays build nests and lay eggs in March or even February, when snow is deep in the boreal forest.[20][21] Male grey jays choose a nest site in a mature coniferous tree[23] and take the lead in construction.[20] Grey jay nests were found in black spruce (Picea mariana), white spruce (Picea glauca), and balsam fir (Abies balsamea) trees in Ontario and Quebec, with black spruce predominating.[20][21] Cup-shaped nests[23] were constructed with brittle dead twigs pulled off of trees, as well as bark strips and lichens. Cocoons of the forest tent caterpillar (Malacosoma disstria) filled the interstitial spaces of the nest.[20] Nests are usually built on the southwestern side of a tree for solar warming and are usually less than one nest diameter from the trunk.[21] Nest height is typically 8 to 30 ft (2.4 to 9.1 m) above the ground.[21] The average height of 264 nests surveyed in Algonquin Provincial Park was 16 ± 9.2 ft (4.9 ± 2.8 m) above ground.[21]

Clutch size is 2 to 5 eggs. The mean clutch sizes of grey jays in Algonquin Provincial Park and La Verendrye Provincial Park were 3.03 and 3.18 eggs, respectively. Incubation is performed only by the female[21] and lasts an average of 18.5 days.[20]

Fledging[edit]

A hatchling

Grey jay young are altricial. Nestling growth is most rapid from the fourth through the tenth day following hatching. Young are fed food carried in the throats of both parents.[20][21] The accompanying nonbreeding third bird does not help with feeding during this period but is driven away by the parents if it approaches the nest.[24][25] Food is a dark brown, viscous paste containing primarily arthropods.[20][21] Young grey jays leave the nest between 22 and 24 days after hatching, after which the third bird begins to participate in foraging and feeding.[20] Natal dispersal distance for the grey jay is a median of 0.0 km for males, 2.8 km (1.7 mi) for females, and a maximum distance of 11.3 km (7.0 mi) for males and females.[22]

After 55 to 65 days, juveniles reach full adult measurements and battle among themselves until a dominant juvenile forces its siblings to leave the natal area.[26] The dominant bird remains with its parents until the following season, while its siblings leave the natal territory to join an unrelated pair who failed to breed. In Strickland's study, two-thirds of dominant juveniles were male.[22]

Survival[edit]

In studies conducted in Ontario and Quebec, the mortality rate for dominant juveniles was 52%, and mortality was 85% for juveniles who left the parents' territory between fledging in June to approximately mid-October. From fall to the following breeding season in March, further juvenile mortality was 50%. Territory-holding adult grey jays experienced low mortality rates (15.1 and 18.2% for males and females, respectively).[22] The oldest known grey jay recaptured in the wild was at least 17 years old.[18] Food-storing birds such as the grey jay may live longer than other species due to the increased probability of food availability.[27]

Feeding[edit]

Grey jays are omnivorous.[20][21] Foods eaten include arthropods,[20] small mammals,[28] nestling birds,[29][30][31] carrion,[20][21] fungi,[20] fruits such as chokecherry (Prunus virginiana),[21] and seeds.[21] Two grey jays were seen eating slime mold (Fuligo septica) near Kennedy Hot Springs in the Glacier Peak Wilderness, Washington. This was the first report of any bird consuming slime mold in the field.[32] Risk and energy expenditure are factors in food selection for the grey jay, which selects food on the basis of profitability to maximize caloric intake. Increased handling, searching, or recognition times for a preferred food item lowers its profitability.[33] Grey jays wrench, twist, and tug food apart, unlike other birds known as jays (such as the blue jay, Cyanocitta cristata) which grasp and hammer their food.[18] Grey jays commonly carry large food items to nearby trees to eat or process for storage, possibly as defense against large scavengers.[20]

Grey jays commonly prey on nestling birds.[31][34] Nests are located visually by moving from perch to perch and scanning surroundings.[20] Grey jay predation on nestling birds is temporally homogeneous throughout the passerine breeding season. Avian nest predation by grey jays is not necessarily higher in fragmented versus unfragmented forest.[29][30][31] Studies of nest predation by grey jays in Quebec have shown that the birds prefer preying on nests in open forest with high prominence of jack pine,[29] and greater rates of predation in riparian forest strips and green-tree retention stands versus clearcuts.[35] This may be due to increased availability of perch sites for avian predators such as the grey jay.[31]

Grey jays are suspected but not proven to prey on nests of the threatened marbled murrelet (Brachyramphus marmoratus) in coastal areas of the Pacific Northwest.[34] Evidence from studies in the Pacific Northwest suggest a moderate increase in nest predation in logged plots adjacent to mature conifer forest, which is the grey jay's preferred habitat.[20][21]

Occasionally, grey jays eat live prey. Lescher and Lescher[28] witnessed a grey jay kill an unidentified small rodent in Wisconsin. Barnard was the first to witness an in-flight grey jay capture of a magnolia warbler (Dendroica magnolia) for consumption.[36] They have been reported to opportunistically hunt young amphibians such as the western chorus frog (Pseudacris triseriata) in Chambers Lake, Colorado, [37] and the long-toed salamander (Ambystoma macrodactylum) in Whitehorse Bluff in Crater Lake National Park in Oregon.[38] Grey jays have been seen landing on moose (Alces alces) to remove and eat engorged winter ticks (Dermacentor albipictus) during April and May in Algonquin Provincial Park. Researchers also found a grey jay nest containing a brooding female, three hatchlings, and three warm, engorged winter deer ticks. Because the ticks were too large for the hatchlings to eat, it was hypothesized that the ticks may have served as "hot water bottles", keeping hatchlings warm when parents were away from the nest.[39]

Caching[edit]

Pair of jays feeding their nestlings

Grey jays are "scatterhoarders", caching thousands of food items during the summer for use the following winter.[22][25][33][40][41] Any food intended for storage is manipulated in the mouth and formed into a bolus that is coated with sticky saliva, adhering to anything it touches. The bolus is stored in bark crevices, under tufts of lichen, or among conifer needles. Cached items can be anything from carrion to bread crumbs.[21] A single grey jay may hide thousands of pieces of food per year, to later recover them by memory, sometimes months after hiding them.[21][42] Cached food is sometimes used to feed nestlings and fledglings.[21]

When exploiting distant food sources found in clearings, grey jays were observed temporarily concentrating their caches in an arboreal site along the edge of a black spruce forest in interior Alaska. This allowed a high rate of caching in the short term and reduced the jay's risk of predation. A subsequent recaching stage occurred, and food items were transferred to widely scattered sites to reduce theft.[43]

Caching is inhibited by the presence of Steller's jays[44] and grey jays from adjacent territories,[40][41] which follow resident grey jays to steal cached food.[44] Grey jays carry large food items to distant cache sites for storage more often than small food items. To prevent theft, they also tend to carry valuable food items further from the source when caching in the company of one or more grey jays.[41] Scatterhoarding discourages pilferage by competitors. Cache thievery increases with increased cache density.[40]

Caching behaviour is thought to have evolved for several reasons. It allows for permanent residence in boreal and subalpine forests,[20] ensures a food source in areas with high elevations and cyclic availability of food resources, and favours the retention of young and a kin-selected social organization.[27] In southern portions of the grey jay's range, food is not cached during summer because of the chance of spoilage and the reduced need for winter stores.[20]

Predators[edit]

Grey jays are consumed by several bird species including great grey owls (Strix nebulosa), northern hawk-owls (Surnia ulula),[45] and Mexican spotted owls (Strix occidentalis lucida).[46] Grey jay remains were found in the nest sites of fisher (Martes pennanti) and American marten (Martes americana).[47] Red squirrel (Tamiasciurus hudsonicus) eat grey jay eggs.[21] Grey jays warn each other of predators by whistling alarm notes, screaming, chattering, or imitating, and/or mobbing predators.[20]

Relationship with humans[edit]

Cultural significance[edit]

Bold grey jay, typical of those individuals accustomed to humans

Found throughout Canada, the bird is popularly known by its once-official name, Canada jay.[48] Another well-known colloquial name is "whisky jack". This is a variation on the name of Wisakedjak, a benevolent trickster and cultural hero in Cree, Algonquin and Menominee mythologies.[49] Alternate spellings for this name include wesakechak, wiskedjak, whiskachon, and wisakadjak.[50]

The grey jay readily capitalizes on novel food sources, including taking advantage of man-made sources of food. To the frustration of trappers using baits to catch fur-bearing animals or early travelers trying to protect their winter food supplies, and to the delight of campers, bold grey jays are known to approach humans for treats and to steal from unattended food stores. According to Maccarone and Montevecchi,[33] human observers do not inhibit grey jays' feeding behaviour; however, Rutter claims that "once having identified man with food it does not forget". He found that after a nesting female was accustomed to being fed by humans she could be enticed to leave the nest during incubation and brooding.[21] These behaviours have inspired a number of nicknames for the grey jay, including lumberjack, meat-bird, venison-hawk, moose-bird, and gorby.[17][51] The Tlingit people of northwestern North America know it as kooyéix or taatl'eeshdéi, "camp robber".[52]

In January 2015, The Royal Canadian Geographical Society's magazine, Canadian Geographic, announced a project to select a national bird for Canada, a designation which the country has never formally recognized.[53] Dubbed the National Bird Project, the organization conducted an online poll inviting Canadians to vote for their favourite bird.[54] The poll closed on 31 August 2016, and a panel of experts convened the following month to review the top five selections: the grey jay, common loon, snowy owl, Canada goose and black-capped chickadee.[55] The project announced on 16 November 2016 that the grey jay was selected as the winner of the contest, and will recommend that the Canadian government make the selection official as part of Canada's sesquicentennial celebrations in 2017.[56][57]

Conservation[edit]

Grey jays are widespread in boreal and subalpine habitats only lightly occupied by humans. Significant human impacts may nevertheless occur through anthropogenic climate warming. Grey jays at the northern edges of their range may benefit from the extension of spruce stands out onto formerly treeless tundra. A published study[58] has documented a decline at the southern edge of the grey jay’s range, however, and plausibly linked a local decline in productivity to warmer temperatures in preceding autumns. Such warm temperatures may trigger spoilage of the perishable food items stored by grey jays upon which success of late winter nesting partly depends.[59]

References[edit]

 This article incorporates public domain material from the United States Department of Agriculture document "Perisoreus canadensis".

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Further reading[edit]

  • Madge, S. and H. Burn (1994). Crows and Jays: A Guide to the Crows, Jays and Magpies of the World. Boston, Houghton Mifflin.

External links[edit]