Grey jay

"Whisky jack" redirects here. For the Cree mythological figure, see Wisakedjak. For other uses, see Whiskeyjack (disambiguation).
Grey jay
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Corvidae
Genus: Perisoreus
Species: P. canadensis
Binomial name
Perisoreus canadensis
(Linnaeus, 1766)
Subspecies

11 subspecies; see text

Grey Jay range

The grey jay (Perisoreus canadensis), also gray jay, Canada jay[2] or whisky jack,[3] 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. 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.

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.

Description

The grey jay is a relatively large songbird. A typical 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). This is not a sexually dimorphic species, like most corvids, but males are slightly larger than females. These birds can live for up to 19 years.[4] Its build is stocky, with thick feathers, long tails, and broad, rounded wings. These birds have round heads with short, stout bills.[5]

Distribution

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

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.[6][7]

Habitat and distribution

Perisoreus canadensis obscurus in Mount Rainier National Park

The vast majority of grey jays live where there is a strong presence of one or more 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.

Behaviour

Mating

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.[7] Grey jay pairs breed during March and April, depending on latitude,[7][9][10] in permanent, all-purpose territories.[7][9][10][11] Second broods are not attempted, perhaps allowing greater time for food storage.[7][9]

Grey, sooty plumage of a juvenile

Grey jays cooperatively breed.[10][12][13] During the nest-building phase of the subsequent breeding season, approximately 65% of grey jay trios included "stayers" from the previous spring and their parents, and approximately 30% of trios included an unrelated "leaver". Occasionally, two nonbreeders accompany a pair of adults. "Stayers" may eventually inherit the natal territory and breed, and "leavers" may eventually fill a vacancy nearby or form a new breeding pair on previously unoccupied ground.[10] The role of "stayers" is to retrieve caches and bring food to younger siblings;[12][13] however, this is only allowed by the parents during the postfledgling period.[10][12][13] Until then, parents are hostile toward the "stayer". This may reduce the frequency of predator-attracting visits to the nest when young are most vulnerable. The benefits of allofeeding 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.[12]

Nesting

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.[7][9] Male grey jays choose a nest site in a mature coniferous tree[11] and take the lead in construction.[7] 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.[7][9] Cup-shaped nests[11] 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.[7] Nests are usually built on the southwestern side of a tree for solar warming and are usually <1 nest diameter from the trunk.[9] Nest height is typically 8 to 30 ft (2.4 to 9.1 m) above the ground.[9] The average height of 264 nests surveyed in Algonquin Provincial Park was 16 ± 9.2 ft (4.9 ± 2.8 m) above ground.[9]

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[9] and lasts an average of 18.5 days.[7]

Fledging

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.[7][9] The accompanying nonbreeding third bird ("stayer") does not help with feeding during this period but is driven away by the parents if it approaches the nest.[12][13] Food is a dark brown, viscous paste containing primarily arthropods.[7][9] Young grey jays leave the nest between 22 and 24 days after hatching, after which the "stayer" begins to participate in foraging and feeding.[7] 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.[10]

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.[14] 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 "stayers" were male.[10]

Survival

In studies conducted in Ontario and Quebec, the mortality rate for nonbreeding dominant juveniles ("stayers") was 52%, and mortality was 85% for nonbreeding "leavers" between fledging in June to approximately mid-October. From fall to the following breeding season in March, further nonbreeder mortality was 50%. Territory-holding adult grey jays experienced low mortality rates (15.1 and 18.2% for males and females, respectively).[10] The oldest known female grey jay was 16 years old, and one male was at least 14 years old.[7] Food-storing birds such as the grey jay may live longer than other species due to the increased probability of food availability.[15]

Grey jays are omnivorous.[7][9] Foods eaten include arthropods,[7] small mammals,[16] nestling birds,[17][18][19] carrion,[7][9] fungi,[7] fruits such as chokecherry (Prunus virginiana),[9] and seeds.[9] 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.[20]

Occasionally, grey jays eat live prey. Lescher and Lescher[16] witnessed a grey jay kill an unidentified, live small rodent in Wisconsin. Barnard was the first to witness an in-flight grey jay capture of a magnolia warbler (Dendroica magnolia) for consumption.[21]

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 winter deer 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.[22]

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.[23]

Foraging behaviour

Grey jays do not hammer food with their bill as do other jays, but wrench, twist, and tug food apart. Grey jays commonly carry large food items to nearby trees to eat or process for storage, possibly as defense against large scavengers.[7] They are "scatterhoarders", caching food items among scattered sites for later consumption.[24][25]

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. A single grey jay may hide thousands of pieces of food per year, to later recover them by memory, sometimes months after hiding them.[9][26]

Risk and energy expenditure are factors in food selection for 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.[24]

The grey jay takes advantage of man-made sources of food, hence the names "camp robber" and "whisky jack". According to Maccarone and Montevecchi,[24] human observers do not inhibit grey jays' feeding behaviour; however, Rutter[9] 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.[9]

Predation

Grey jays commonly prey on nestling birds.[19][23] Nests are located visually by moving from perch to perch and scanning surroundings.[7] 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.[17][18][19]

Boulet and others [17] examined bird nest predation in a commercially fragmented boreal black spruce forest intermixed with jack pine, balsam fir, quaking aspen, and paper birch near Lake Saint-Jean, Quebec. Grey jays directed their attacks on artificial arboreal nests more often than artificial ground nests. Depredation of nests was positively related to the presence of the lake and jack pine. Grey jays may have preferred preying on avian nests in jack pine versus black spruce habitat because jack pine forests were more open, and trees did not conceal nests as well. Grey jays may have favoured foraging along lakeshores and moist patches due to the high density of insects. No relationship was found between the fragmented forest and predation.[17]

The potential for egg predation by grey jays was greater in riparian forest strips than in clearcuts in a second-growth boreal balsam fir forest in Montmorency Forest, Quebec.[27]

Stuart-Smith and Hayes[18] examined the influence of residual tree density on predation of artificial and natural songbird nests. The study took place in the White River and Lussier River Watershed, southeastern British Columbia, in a forest dominated by Douglas-fir, white spruce, and western larch. Twenty-four plots of similar age were chosen (16 logged, 8 burned by wildfire); they varied in residual tree density between 0 and 180 trees/ha. Residual trees apparently did not increase predation on nesting songbirds by the grey jay. However, a moderate increase in nest predation occurred in logged plots adjacent to or surrounded by mature conifer forest, which is the preferred habitat for grey jays.[7][9] Retaining residual trees would outweigh the possible increased risk of nest predation, except in areas where nesting birds are at very low numbers and potential risk by grey jays is high.[18]

When predation rates on bird nests by the grey jay were compared in clearcut, green-tree retention stands, and mature western hemlock stands in the west-central Oregon Cascade Ranges, predation rates were highest in green-tree retention stands. This may have been due to increased availability of perch sites for avian predators such as the grey jay.[19]

Caching

Pair of jays feeding their nestlings

Grey jays cache thousands of food items during the summer for use the following winter.[10][13][28][29] Caching behavior is thought to have evolved for several reasons. It allows for permanent residence in boreal and subalpine forests,[7] ensures a food source in areas with high elevations and cyclic availability of food resources, and favors the retention of young and a kin-selected social organization.[15] 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.[7] Cached items can be anything from carrion to bread crumbs and are formed into a bolus before being cached.[9] Cached food is sometimes used to feed nestlings and fledglings.[9]

Caching is inhibited by the presence of Steller's jays[30] and grey jays from adjacent territories,[28][29] which follow resident grey jays to steal cached food.[30] 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.[29] Scatterhoarding discourages pilferage by competitors. Cache thievery increases with increased cache density.[28]

When exploiting distant food sources found in clearings, grey jays temporarily concentrated 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.[25]

Predators

Grey jays are consumed by several bird species including great grey owls (Strix nebulosa), northern hawk-owls (Surnia ulula),[31] and Mexican spotted owls (Strix occidentalis lucida).[32] Grey jay remains were found in the nest sites of fisher (Martes pennanti) and American marten (Martes americana).[33] Red squirrel (Tamiasciurus hudsonicus) eat grey jay eggs.[9]

Grey jays warn each other of predators by whistling alarm notes, screaming, chattering, or imitating, and/or mobbing predators.[7]

Relationship with humans

Cultural significance

Bold grey jay, typical of those individuals accustomed to humans

The bird's most notable 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.[34] Alternate spellings for this name include wesakechak, wiskedjak, whiskachon, and wisakadjak.

Grey jays readily capitalize on novel food sources, including food sources introduced by humans living on or passing through their territories. 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, many individual grey jays quickly learn that humans can be an excellent source of food, even coming to the hand for bread, raisins, or cheese. Such familiarity has inspired a long list of colloquial names for the grey jay. In addition to the once official 'Canada jay', there are, lumberjack, meat-bird, camp robber, venison-hawk, moose-bird, and gorby.

In January 2015, the Royal Canadian Geographical Society and Canadian Geographic magazine announced a project to select a National Bird of Canada, dubbed the National Bird Project, consisting of an online poll inviting Canadians to vote for their favourite bird.[35] 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.[36] The project announced in November 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.[37][38]

Conservation

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 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.

References

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

  1. ↑ BirdLife International (2012). "Perisoreus canadensis". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. ↑ Peterson, RT (1947). A Field Guide to Eastern Birds (Second Revised ed.). Boston: Houghton Mifflin Co.
  3. ↑ MacKinnon, Bobbi-Jean (23 November 2016). "CBC's spelling of grey jay causes some readers to squawk". CBC News. Retrieved 27 November 2016.
  4. ↑ "Grey Jay". Oiseaux-Birds. Retrieved 18 November 2016.
  5. ↑ "Grey Jay". All About Birds. Retrieved 18 November 2016.
  6. 1 2 3 4 5 6 7 8 9 10 American Ornithologists' Union (1957). Checklist of North American birds. 5th ed. Baltimore, MD: The Lord Baltimore Press, Inc.
  7. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Strickland, Dan; Ouellet, Henri. (1993). Grey Jay. In: Poole, A.; Stettenheim, P.; Gill, F., eds. Birds of North America, No. 40. Philadelphia, PA: The Academy of Natural Sciences; Washington, DC: The American Ornithologists' Union.
  8. ↑ Hoffmann, Ralph & Brooks, Allan (Major) (illustrator) (1927). Birds of the Pacific States, The Riverside Press, Cambridge, Massachusetts, USA (Houghton Mifflin Company, Boston, Massachusetts, USA), p. 224: description with black-and-white illustration of Oregon Jay on conifer branch.
  9. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Rutter, Russell J. (1969). "A contribution to the biology of the Grey Jay (Perisoreus canadensis)". Canadian Field-Naturalist. 83 (4): 300–316.
  10. 1 2 3 4 5 6 7 8 9 Strickland, Dan (1991). "Juvenile dispersal in Grey Jays: dominant brood member expels siblings from natal territory". Canadian Journal of Zoology. 69 (12): 2935–2945. doi:10.1139/z91-414.
  11. 1 2 3 Hobson, Keith A.; Schieck, Jim (1999). "Changes in bird communities in boreal mixedwood forest: harvest and wildfire effects over 30 years". Ecological Applications. 9 (3): 849–863. doi:10.1890/1051-0761(1999)009[0849:CIBCIB]2.0.CO;2. JSTOR 2641334.
  12. 1 2 3 4 5 Strickland, Dan; Waite, Thomas A. (2001). "Does initial suppression of allofeeding in small jays help to conceal their nests?". Canadian Journal of Zoology. 79 (12): 2128–2146. doi:10.1139/cjz-79-12-2128.
  13. 1 2 3 4 5 Waite, Thomas A.; Strickland, Dan (1997). "Cooperative breeding in Grey Jays: philopatric offspring provision juvenile siblings". The Condor. 99 (2): 523–525. doi:10.2307/1369960. JSTOR 1369960.
  14. ↑ Ha, James C.; Lehner, Philip N. (1990). "Notes on Grey Jay demographics in Colorado". The Wilson Bulletin. 102 (4): 698–702. JSTOR 4162942.
  15. 1 2 Roberts, Robert Chadwick (1976). Ecological relationships in the acorn woodpecker (Melanerpes formicivorus), with reference to habitat characteristics, foraging strategies, and the evolution of food-storing behavior. Davis, CA: University of California. Dissertation
  16. 1 2 Lesher, Fred; Lesher, Jolene (1984). "Gray Jay takes live mammal". The Loon. 56 (1): 72–73.
  17. 1 2 3 4 Boulet, Marylene; Darveau, Marcel; Belanger, Louis (2000). "A landscape perspective of bird nest predation in a managed boreal black spruce forest". Ecoscience. 7 (3): 281–289.
  18. 1 2 3 4 Stuart-Smith, A; Hayes, John P. (2003). "Influence of residual tree density on predation of artificial and natural songbird nests". Forest Ecology and Management. 183: 159. doi:10.1016/S0378-1127(03)00104-X.
  19. 1 2 3 4 Vega, Robyn M. S. (1993). Bird communities in managed conifer stands in the Oregon Cascades: habitat associations and nest predation. Corvallis, OR: Oregon State University. Thesis
  20. ↑ Sutherland, John B.; Crawford, Ronald L (1979). "Gray Jay feeding on slime mold". The Murrelet. 60 (1): 28.
  21. ↑ Barnard, William H. (1996). "Juvenile Grey Jay preys upon magnolia warbler" (PDF). Journal of Field Ornithology. 67 (2): 252–253.
  22. ↑ Addison, E. M.; Strickland, R. D.; Fraser, D. J. H. (1989). "Gray Jays, Perisoreus canadensis, and common ravens, Corvus corax, as predators of winter ticks, Dermacentor albipictus". The Canadian Field-Naturalist. 103 (3): 406–408.
  23. 1 2 Raphael, Martin G.; Mack, Diane Evans; Marzluff, John M.; Luginbuhl, John M. (2002). "Effects of forest fragmentation on populations of the marbled murrelet". Studies in Avian Biology. 25: 221–235.
  24. 1 2 3 Maccarone, Alan D.; Montevecchi, W. A. (1986). "Factors affecting food choice by Grey Jays". Bird Behavior. 6 (2): 90–92. doi:10.3727/015613886792195216.
  25. 1 2 Waite, Thomas A.; Reeve, John D. (1997). "Multistage scatter-hoarding decisions in the Grey Jay (Perisoreus canadensis)". Bird Behavior. 12 (1/2): 7–14. doi:10.3727/015613897797141335.
  26. ↑ "Grey Jay Research in Algonquin Park". The Science Behind Algonquin's Animals. Retrieved 18 November 2016.
  27. ↑ Darveau, Marcel; Belanger, Louis; Huot, Jean; Melancon, Eric; DeBellefeuille, Sonia (1997). "Forestry practices and the risk of bird nest predation in a boreal coniferous forest". Ecological Monographs. 7 (2): 572–580. doi:10.1890/1051-0761(1997)007[0572:FPATRO]2.0.CO;2. JSTOR 2269522.
  28. 1 2 3 Waite, Thomas A. (1988). "A field test of density-dependent survival of simulated Grey Jay caches". The Condor. 90 (1): 247–249. doi:10.2307/1368458. JSTOR 1368458.
  29. 1 2 3 Waite, Thomas A. (1992). "Social hoarding and a load size-distance relationship in Grey Jays". The Condor. 94 (4): 995–998. doi:10.2307/1369297. JSTOR 1369297.
  30. 1 2 Burnell, Kristi L.; Tomback, Diane F. (1985). "Steller's jays steal Grey Jay caches: field and laboratory observation". Auk. 102 (2): 417–419. doi:10.2307/4086793. JSTOR 4086793.
  31. ↑ Rohner, Christoph; Smith, James N. M.; Stroman, Johan; Joyce, Miranda; Doyle, Frank I.; Boonstra, Rudy (1995). "Northern Hawk-Owls in the Nearctic boreal forest: prey selection and population consequences of multiple prey cycles". The Condor. 97 (1): 208–220. doi:10.2307/1368997. JSTOR 1368997.
  32. ↑ U.S. Department of the Interior, Fish and Wildlife Service (1995). Recovery plan for the Mexican spotted owl: Vols. 1–2. Albuquerque, NM: U. S. Department of the Interior, Fish and Wildlife Service.
  33. ↑ Henry, Stephen E.; Raphael, Martin G.; Ruggiero, Leonard F. (1990). "Food caching and handling by marten". The Great Basin Naturalist. 50 (4): 381–383. PDF copy
  34. ↑ "Native Languages of the Americas. (2011). Native Languages of the Americas: Wesakechak Stories and other Cree Legends.".
  35. ↑ Galloway, Gloria (22 January 2015). "Race is on to pick the national bird of Canada". The Globe and Mail. Ottawa. Retrieved 17 November 2016.
  36. ↑ "National Bird Project". Canadian Geographic. Retrieved 17 November 2016.
  37. ↑ "Step aside, loon: Geographic society plucks grey jay as Canada's national bird". Bell Media Television. Retrieved 17 November 2016.
  38. ↑ Stone, Laura (16 November 2016). "Grey jay gets nod for Canada's national bird". The Globe and Mail.

Further reading

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