Irruptions of the Clark Nutcracker in California

Davis, John M.; Williams, Laidlaw

doi:10.2307/1364965

Cited by 30 publications

(23 citation statements)

References 15 publications

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“…Irruptions.-Aside from the autumnal movements of the Clark's Nutcracker from its breeding grounds to adjacent areas in search of harvestable pine seeds, nutcrackers typically undergo periodic movements far from their mountainous environs to lowland deserts and coastal areas. Major irruptions of the Clark's Nutcracker have occurred during the falls and winters of 1898-99, 1919-20, 1935-36, 1950-51, 1955-56, and 1961-62 (Davis and Williams 1957, 1964 in the Sierra Nevadas of California with milder irruptions occurring occasionally during intervening years.…”

Section: The Effect Of Food Storage On the Clark's Nutcrackermentioning

confidence: 99%

“…These irruptions are closely correlated with the widespread failure of conifer seed crops and probably with high nutcracker population density (Formoso£ 1933;Davis andWilliams 1957, 1964). During years of good seed crops, conditions are favorable for successful breeding and consequently populations increase.…”

Section: The Effect Of Food Storage On the Clark's Nutcrackermentioning

confidence: 99%

“…During years of good seed crops, conditions are favorable for successful breeding and consequently populations increase. In a poor seed crop year, the food shortage is intensified by the high population level and many nutcrackers are forced to leave their montane forest habitat and search for food at lower elevations (Davis and Williams 1957).…”

Section: The Effect Of Food Storage On the Clark's Nutcrackermentioning

confidence: 99%

See 2 more Smart Citations

Coadaptations of the Clark's Nutcracker and the Pinon Pine for Efficient Seed Harvest and Dispersal

Wall¹,

Balda²

1977

Ecological Monographs

320

214

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Clark's Nutcracker (Nucifraga columbiana) is one of four species of corvids that commences harvesting, transporting, and caching the seeds of pinon pine (Pinus edulis) in mid—August. Caching continues until inclement weather intervenes or the seed crop is depleted. Nutcrackers are efficient at collecting seeds from the trees because the birds discriminate edible and aborted seeds, select cones with higher than average number of good seeds and appear to concentrate on those trees that produce cones with large numbers of good seeds. The use of a sublingual pouch allows the nutcracker to carry up to 95 pinon pine seeds per trip (x = 55). A pouch full of seeds may be carried as far as 22 km from the collecting area (the pinon—juniper woodland, elevation ~ 1800 m) to communal caching areas where the seeds are buried in clumps in subterranean caches at a depth of 2 to 3 cm. These caching areas are on steep, south—facing slopes that are usually free of snow by late winter. Although solitary nesters, the birds, during the nonbreeding season, often form flocks when harvesting seeds. A flock of 150 nutcrackers cached between 3.3—5.0 X 106 pinon pine seeds in the autumn of a good cone crop. Each bird caches between 2.2 and 3.3 X its needed energetic requirements for the insect—free portion of the year. Some of the unrecovered seeds germinated and grew. The pinon pine reaches its highest density in relatively dry areas below the elevational range of other members of the genus Pinus, but ranges up to 3,100 m into the mixed coniferous forest. This pine has developed a number of traits that enhance its efficiency to be located and dispersed by the birds. The seeds are unusually large, of high energy value, and have relatively thin seed coats. The large size improves the germination potential of the seed but also attracts predators and dispersal agents. The seed coat color is markedly different for edible and aborted seeds, thus labeling them for visually oriented seed harvesters. Most pinon pine cones are oriented outward and upward which increases illumination of the seeds and tends to hold them in the cone. The pinon pine displays the seeds in its cones more readily than wind—dispersed pines by opening the seed—bearing cone scales to a uniform angle. Pinon pine seeds are retained for a long period of time in the cone because they are held in deep depressions on the cone scales by small flanges. This constellation of features indicated an evolutionary strategy on the part of the pinon pine to exploit and encourage members of the seed—caching guild to disperse the seeds. Deposition sites are presumably more favorable for germination than those obtained by simply broadcasting the seeds over a wide area. Individual seedlings potentially experience immediate intraspecific competition because the seeds are cached in clumps. Only one seedling, presumably the strongest, fastest—growing individual, survives. The benefits of this system to the nutcracker are that the bird has a supply of energy for the most unproductive months of the ye...

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Section: The Effect Of Food Storage On the Clark's Nutcrackermentioning

confidence: 99%

Section: The Effect Of Food Storage On the Clark's Nutcrackermentioning

confidence: 99%

Section: The Effect Of Food Storage On the Clark's Nutcrackermentioning

confidence: 99%

See 1 more Smart Citation

Coadaptations of the Clark's Nutcracker and the Pinon Pine for Efficient Seed Harvest and Dispersal

Wall¹,

Balda²

1977

Ecological Monographs

320

214

View full text Add to dashboard Cite

show abstract

“…Although we found no evidence that food subsidies negatively affect the use of whitebark pine by Clark's Nutcrackers in Mount Rainier National Park, food subsidy may still be an important energy source for Clark's Nutcrackers in years with low seed crops. Because Clark's Nutcrackers, like many granivorous birds, respond to cone crop failures and seed shortages with emigration or irruption (Davis and Williams 1957, 1964, Bock and Lepthien 1976, food subsidy from visitors to Mount Rainier could help prevent localized population extinctions and lower the risk of mutualism disruption (McKinney et al 2009). This may be especially relevant because persistent threats to whitebark pine trees and cone production, particularly white pine blister rust, are widespread in western North America and throughout the range of whitebark pine (Kendall and Keane 2001, Smith et al 2008, Tomback and Achuff 2010.…”

Section: Measuring Occupancy or Densitymentioning

confidence: 99%

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2015

The Condor

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“…They bury more whitebark pine seeds than they require for winter and spring food, and many seed caches are in sites suitable for whitebark pine establishment . Nutcrackers are so dependent on whitebark pine and other conifer seeds that years of widespread cone crop failure cause nutcracker irruptions in which the birds may move hundreds of miles from their normal range (Davis and Williams 1964). Use of pine seed caches to feed nestlings and fledglings enables Clark's nutcrackers to nest earlier than other'passerines, which must wait until insects are available for feeding.…”

Section: Introductionmentioning

confidence: 99%

Proceedings-symposium on whitebark pine ecosystems: Ecology and management of a high-mountain resource; 1989 March 29-31; Bozeman, MT

Schmidt¹,

McDonald²

1990

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Irruptions of the Clark Nutcracker in California

Cited by 30 publications

References 15 publications

Coadaptations of the Clark's Nutcracker and the Pinon Pine for Efficient Seed Harvest and Dispersal

Coadaptations of the Clark's Nutcracker and the Pinon Pine for Efficient Seed Harvest and Dispersal

Full Issue

Proceedings-symposium on whitebark pine ecosystems: Ecology and management of a high-mountain resource; 1989 March 29-31; Bozeman, MT

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