© Richard Stevens
The following lists are speculative. They are based on pinyon jay distribution
information and the habitat characteristics and species composition of communities
pinyon jays are known to occupy during migration and breeding. Abundance of pinyon
jays in the community types listed is variable. Pinyon jays are rarely observed in
some of the following communities and are quite common in others. See
Preferred Habitat for more details.
FRES21 Ponderosa pine
FRES26 Lodgepole pine
FRES30 Desert shrub
FRES33 Southwestern shrubsteppe
FRES34 Chaparral-mountain shrub
STATES/PROVINCES: (key to state/province abbreviations)
In a study conducted in Washington County in southwestern Utah by Webb , pinyon jays occurred in the Great Basin-Mohave Desert ecotone, dominated by blackbrush (Coleogyne ramosissima).
Terry Spivey, www.forestryimages.org
The pinyon jay is a permanent resident of pinyon-juniper (Pinus-Juniperus spp.)
woodlands and low-elevation ponderosa pine (P. ponderosa) forests  in the
southwestern United States. Pinyon-juniper woodlands are comprised primarily of Colorado
pinyon (P. edulis) and Utah juniper (J. osteosperma) [72,73,79] and cover vast
acreages in Colorado, northern Arizona, Utah, and Nevada . Other pinyon and juniper species
occurring in these woodlands include singleleaf pinyon (P. monophylla), Parry pinyon
(P. quadrifolia), Mexican pinyon (P. cembroides), alligator juniper
(J. deppeana), Rocky Mountain juniper (J. scopulorum), and California juniper
(J. californica) [79,121]. The pinyon jay relies on singleleaf pinyon in the northwestern
portion of its range and Colorado pinyon in the southeastern portion of its range . Ponderosa
pines of the southwestern United States include interior ponderosa pine (P. p.
var. scopulorum) and Arizona pine (P.p. var. arizonica). In this
review, "pinyon" refers to both Colorado pinyon and singleleaf pinyon, and "ponderosa
pine" refers to interior ponderosa pine and Arizona pine, unless otherwise specified.
TIMING OF MAJOR LIFE HISTORY EVENTS:
Mating: Pinyon jays form large flocks that are maintained in a variety of forms throughout the year. The breeding season during January and February is the only time of the year when the composition of the flock changes dramatically. Two flocks are formed, 1 with breeding birds and 1 with yearling non-breeding birds. A 3rd flock may form at this time, composed of breeding pairs that were unsuccessful in their 1st breeding attempt in order to try a 2nd breeding attempt. Despite separation into separate flocks at times, a high degree of sociality continues to be maintained [10,11].
Pinyon jays appear to form perennial, monogamous pair bonds [87,89,90] that last an average of 2.5 years. Breeding is initiated in males and females at 2 years and 1.56 years of age, respectively. Males average 1.63 mates/lifetime and females average 1.43 mates/lifetime .
Pinyon-juniper woodlands [42,72] and ponderosa pine forests [10,49,72] are utilized for reproduction. Pinyon jays are stimulated by increased photoperiod length and begin breeding in January  or early February. Breeding may occur again in August based on the abundance of green Colorado pinyon cones and seeds, which stimulates and accelerates the growth of testes [82,83]. Breeding activities from nest-building to the feeding of fledglings are related to the availability of conifer seeds and have been recorded for every month except December [10,82,83,89]. Reproductive success may be maximized following large Colorado pinyon seed crops. These seed crops ripen at the end of August and enable pinyon jays to cache plenty of seeds and therefore breed sooner in the year [10,82,83,89], typically beginning in January . In years when bumper crops of pinyon seeds are available, pinyon jays have the opportunity to breed twice, in January or February and again in August . When the pinyon crop fails, pinyon jays forego late-winter breeding and instead breed in August when crops of pinyon seeds are ripe . "Courtship parties", consisting of all adult birds in the flock, are formed. Pinyon jays in these "courtship parties" fly several miles away from the group foraging area to breed in a colony [10,87].
Balda and Bateman  studied a flock of 250 pinyon jays in a ponderosa pine forest and adjacent pinyon-juniper woodland for 2 1/2 years near Flagstaff, Arizona. During January or February, the make-up of the pinyon jay flock changed dramatically as courtship activities increased. The flock was together in early morning for foraging, then "courtship parties" flew up to 900 feet (274 m) away from the feeding flock for courtship activities. Courting pairs left and re-entered the main flock throughout the day.
Nesting: Nesting occurs from late February to April [10,72]. Food availability is an important factor in the selection of nesting grounds . Nest building takes place in loose colonies and is synchronized among pairs in the "courtship party" [10,72,87]. During nesting, breeding pairs of birds roost with the main flock and feed as a unit for 1.5 hours each morning .
Nests are built in pinyon , western juniper (J. occidentalis) , or ponderosa pine trees [49,72] and are composed of twigs and shredded bark . Pinyon jays living in urban areas of Flagstaff, Arizona, were observed building their nests from trash, paper, and synthetic materials. Nests were built an average height of 18.4 feet (5.6 m) off of the ground in ponderosa pine trees with large amounts of cover above . Nests are built 50 to 500 feet (15-152 m) apart from each other .
Pinyon jays appear to be highly adaptive. For example, a study conducted by Marzluff  concluded that pinyon jays learned to modify their nest site location based on prior experience. Following at least 2 encounters with predators, pinyon jays learned to avoid building their nests in exposed areas of trees. Pinyon jays 7 or more years old learned to nest at low heights, enhancing concealment, and built their nests further out from the trunk early in the season in order to increase solar warming  and reduce the energy costs of incubation . Galaldon  found that pinyon jays who built their nests within 98 feet (30 m) of roads in Flagstaff, Arizona, experienced higher nest success than nonroadside nests.
Females typically incubate 3 to 5 eggs [72,89]. Clutches measured in Flagstaff, Arizona, commonly contained 4 eggs, but in some years over 40% of all nests contained 3 or fewer eggs. Large clutches of 4 or more eggs were more common in years of abundant Colorado pinyon seeds .
During incubation, males leave the females and form their own feeding flock . Incubating females are fed pinyon and ponderosa pine seeds by their mates [18,72,87]. Marzluff and Balda  found that females were fed at a rate of about once every 73 minutes during incubation. Eggs are typically incubated for 17 days before hatching .
In a ponderosa pine forest near Flagstaff, Arizona, pairs of birds not successful in their 1st nesting attempt formed satellite nesting colonies composed of 3 to 12 nests in late April. These satellite colonies were scattered up to 0.75 miles (1.2 km) in all directions from the initial nesting location . Nest success increased with successive attempts; however, the number of young fledged per nest did not increase .
Fledging: In Balda and Bateman's  study, the fledging of all young pinyon jays occurred no more than 6 days apart from different nests due to the synchronization of breeding. To protect fledglings from the cold, females remained on the nests continuously, and females and young were fed regurgitated ponderosa pine seeds. No more than 2 male birds fed nestlings for the first 12 to 15 days following hatching. Up to 7 adult male birds, probably sons of the nesting pair from the previous year , cooperatively fed nestlings during the last 4 days of nestling life and 20 days after leaving the nest. Some adult pinyon jays that were unsuccessful in their 1st and/or 2nd nesting attempts have been seen assuming a parental role for other young birds .
Young pinyon jays fledge approximately 3 weeks following hatching . Eight days after leaving the nest , the young learn to feed themselves a diet of mainly insects [10,18,75,87] and soft plants . Pinyon seeds and ponderosa pine seeds are eaten as a reserve food [18,75,87]. The fledgling's parents continue to feed them for up to 1 month, but at a reduced rate. Immature pinyon jays become independent at 8 weeks. After fledging, adults and young form a tightly knit feeding group until late summer . In the fall, juveniles of both sexes either become permanent members of the flock that they were born into, or leave to become members of other flocks. Young females usually leave their natal flock to find mates in new flocks and males stay with their natal flock to either breed or help their parents to breed .
Survival: In general, adults have a better chance of survival than yearlings and yearlings have a better chance of survival than juveniles . Nest failure is "high" during years when pinyons do not produce seeds. Breeding during late winter and early spring can produce fewer young that survive to maturity except in years following a major pinyon seed crop. Breeding for a 2nd time in August or September may result in high mortality of nestlings if the weather deteriorates rapidly in the late fall .
Marzluff and Balda  studied 708 pinyon jays in Flagstaff, Arizona, from 1972-1984. The heaviest mortality of pinyon jays occurred in the fall, perhaps due to increased foraging activity in relatively unfamiliar areas, associated with the pinyon seed harvest. An average of 74% of adults, 62% of yearlings and 41% of juveniles survived each year. Female pinyon jays experienced lower survivorship than males, perhaps because they perform the incubation and brooding.
In another study by Marzluff and Balda  in Flagstaff, Arizona, survivorship of all age classes of pinyon jays was more strongly correlated with weather than with pinyon seed crop variations. Juveniles and yearlings had a better chance of survival when spring weather was warm and wet and pinyon crops were large compared to snowy springs and poor pinyon seed crops. Adults survived better during warm, wet, spring weather also but experienced highest survival during intermediate versus large pinyon seed crops. This may have been due to increased activity during harvest in large seed crop years and increased exposure to predators.
Following a study of 2 pinyon jay flocks near Flagstaff, Arizona, Clark and Gabaldon  suggested that nest desertions by adults may be a response to low-temperature thermal stress of nestlings. Broods too young to thermoregulate may die from low-temperature thermal stress when left unattended. This thermal stress may be responsible for nest desertions before the chicks die. Nest desertion may also occur following partial depredation of the nest because of the high probability that a predator may return.
Preferred habitat: Pinyon jays prefer pinyon-juniper woodlands [42,47,72,102] and ponderosa pine forests [10,10,41,49,72].
Pinyon jays interact in a mutual relationship with the pinyon [9,72,83,93]. Pinyon trees provide pinyon jays with food, nesting and roosting sites, and breeding stimuli. Pinyon jays influence seed dispersal [57,58,83,125], establishment [29,55,57,72,125], and genetic structure of pinyon populations .
Pinyon jays use Colorado pinyon in the southeastern portion of their range and singleleaf pinyon in the northwestern portion of their range . The Colorado pinyon begins to bear cones at 25 years of age  and produces "substantial" nut crops at interval of 4 to7 years [12,56], and sometimes every 3 to 5 years . Good cone crops tend to be localized and occur at irregular and infrequent intervals but are geographically synchronous [83,126], perhaps to counteract seed predation . Bumper seed crops of the Colorado pinyon are episodic, and are probably linked to favorable climatic conditions [55,58]. For more details about the botanical and ecological characteristics of the Colorado pinyon, see Colorado pinyon.
Singleleaf pinyon may not produce cones until 35 years of age with a 2- to 7-year interval between cone production years . Maximum seed production occurs when trees are 75 to 100 years old .For more botanical and ecological information about the singleleaf pinyon, see singleleaf pinyon.
The climate, precipitation, elevation, and soil types of pinyon-juniper and ponderosa pine habitats are described in the following section.
Climate: Pinyon-juniper woodlands are characterized as arid, semiarid, or occasionally, dry subhumid . The mean annual temperature varies from 40°to 61° F (4°-16° C) . The climate of ponderosa pine forests in the western United States is arid to semiarid . Weather is an important factor influencing the breeding success and survival of pinyon jays (see Mating and Survival).
Precipitation: The annual mean precipitation in pinyon-juniper woodlands of the southwestern United States varies widely, depending on elevation, topography, and geography. Precipitation ranges from 10 inches (254 mm) at low elevations to 22 inches (559 mm) at high elevations [55,117,134]. Spring and summer are times of drought , and Colorado pinyon and juniper are highly drought resistant . Snow depths are not great, except at higher elevations and northern latitudes, but even then, melting occurs within a few days, especially on south-facing slopes . Ponderosa pine forests in the western United States experience extreme variations in precipitation, receiving no snow some years and up to 100 inches (2,540 mm) in other years. Heavy spring snowfall in both habitats can create difficult nesting conditions for pinyon jays .
Elevation: Pinyon-juniper woodlands occur on foothills, mesas, plateaus and low mountains from 4,000 to 8,000 feet (1,219-2,438 m) elevation [10,55,58,64,105,117,131]. Ponderosa pine forests in the western United States are most common from 6,000 to 8,500 feet (1,800-2,600) . Pinyon jays have been noted foraging with Clark's nutcrackers (Nucifraga columbiana) at elevations up to 11,500 feet (3,505 m) in northern Arizona .
Soil: Pinyon-juniper woodlands occur in areas with a wide range of soils [53,117], with parent materials composed of limestone, lava, and sandstone . Soil textures range from coarse, rocky gravels to fine, compacted clays [81,117]. Ponderosa pine forests in the western United States occur on igneous and sedimentary parent materials including basalt, volcanic cinder, limestone, and sandstone . Conifer seeds are buried by pinyon jays in areas sparsely covered with vegetation, with patches of bare soil and rocks, indicating well-drained soil .
Specific data about the size of pinyon jay's home range are currently unavailable.
Pinyon jays utilize pinyon, western juniper  and ponderosa pine [10,49] trees for cover.
Roosting sites rarely occur in the last area that was used for foraging that day. Before roosting,
a flock of pinyon jays in northern Arizona flew 1 to 3 miles (1.6- 4.8 km) from the feeding site.
Roosting birds clumped together in groups of 3 to 5 individuals .
Pinyon jays are morphologically and behaviorally specialized to exploit pinyon seeds for food [10,83]. Pinyon seeds are heavy and wingless, and not suited for wind dissemination. Their dispersal requires birds, animals, and humans [9,21,29,54,56,72,75]. The seeds of the Colorado pinyon and singleleaf pinyon are very nutritious. Colorado pinyon seeds contain 14% protein, 62% to 71% fat, and 18% carbohydrate. Singleleaf pinyon seeds contain 10% protein, 23% fat, and 54% carbohydrate. Both contain all of the amino acids and abundant phosphorus, iron, vitamin A, and other nutrients . Pinyon cones require 3 growing seasons to mature ; however, seeds within 1 year old green cones can be eaten by the pinyon jay and are ripe by the end of August . Each cone contains approximately 20 seeds . Ponderosa pine seeds are also an important food for the pinyon jay [10,41,49].
In addition to pinyon and ponderosa pine seeds, pinyon jays eat Rocky Mountain bristlecone pine (Pinus aristata) seeds , limber pine (P. flexilis) seeds, and juniper berries . Insects [18,38,75,83,87] such as caterpillar (Lepidoptera) larvae [83,86], beetles (Coleoptera), grasshoppers (Orthoptera), and ants (Hymenoptera)  make up a large portion of their diet. Spiders (Araneae)  are commonly eaten, and cultivated grains [75,83,86] including corn, sorghum, beans, barley, oats, and wheat are consumed during winter months [75,83,86]. Pinyon jays have also been noted ingesting soil around salt blocks for cattle .
Nestlings eat insects [10,18,75,87], soft plants , and pinyon seeds when they are plentiful [75,83].
Foraging Behavior: Pinyon jays form flocks of 50 to more than 500 [72,75,87] and occasionally thousands of individuals, that begin to forage together in late August [72,75]. Flocking may be an adaptive strategy to increase search efficiency and reduce predation [18,88,89]. Pinyon jays must travel long distances in search of cones during years when almost no pinyon or ponderosa pine cones are produced in an area. Different flocks may criss-cross each other within an area and keep in contact by vocalizations.
Flocks are sometimes formed with the hairy woodpecker (Picoides villosus), downy woodpecker (P. pubescens), northern flicker (Coloptes auratus), Clark's nutcracker, and European starling (Sturnus vulgaris) for a portion of the year, but these species are not important for the maintenance of the flock. The benefits of interspecific flocking are probably for protection from predators during feeding and to assist in locating locally abundant but scattered food .
Pinyon jays forage on the ground and in dead, fallen trees for insects and cached seeds. They also forage in the crevices of live trees for cached pinyon seeds, feed on the tips of ponderosa pine branches where new growth has occurred, and forage in the canopy for pinyon and ponderosa pine cones . If a cone is ripe but closed, the pinyon jay removes it to a place where it can be held open with the bird's feet. Then the bird hammers the cone open with its bill . Pinyon jays can differentiate between filled and empty seeds by a combination of color, weight, and sound produced by clicking seeds with their bills [10,72,83]. Pinyon jays can hold up to 43 ponderosa pine seeds  and 56 pinyon seeds in their expandable esophagus [9,83].
Caching: Cached seeds provide energy for gonad development, courtship, nest building, egg laying and incubation . Pinyon jays travel up to 7.5 miles (12 km) [10,72,83] to cache pinyon and ponderosa pine seeds for later use [10,29,60,72,75,83,87,89]. Seed caching is most common in the fall [72,75,119]. Cached Colorado pinyon seeds comprise up to 90% of the pinyon jay's diet from November through February . One to 7 seeds are placed in each cache , and a single pinyon jay can cache more than 20,000 seeds in 1 season . A flock of pinyon jays in New Mexico was estimated to cache 4.5 million seeds in 1 year . Pinyon jays may recache seeds to avoid seed theft by Steller's jays (Cyanocitta stellerii) .
Seeds are cached on and off of the ground, depending on the season. Seeds are cached on the ground in areas with sparse vegetation and exposed, well-drained soils . Seeds are buried in the litter of dead needles and twigs [10,72], and between organic material and mineral soil . Seeds are cached close to the trunk of trees , most often on the south side where snow melts most quickly [9,10,72,83]. Ground-caching stops when snow covers the ground .
Pinyon jays have been observed caching a significantly (P<0.01) greater number of seeds in above-ground sites during winter. Most seeds were cached in the crevices of tree bark. This was probably due to cold ground temperatures and snow accumulation .
A flock of pinyon jays occupying residential areas near Flagstaff, Arizona, was observed removing and caching sunflower seeds, Colorado pinyon seeds, peanuts, and millet from bird feeders .
Pinyon jays can remember specific locations where their conspecifics cached seeds for at least 2 days. They can remember general locations of cached seeds for at least 7 days. Observational spatial memory may have evolved as a consequence of cache dependence, as a consequence of caching in flocks, and/or a combination of the 2 .
Diet due to season: Pinyon jays forage mainly on pinyon seeds in late summer [10,29,60,72,75,82,83,87,88,89] and ponderosa pine seeds in fall and early winter [10,41]. A flock of pinyon jays in Flagstaff, Arizona, spent 80% of their time foraging in ponderosa pine forests in late November and early December, and 20% of their time foraging in both an open meadow dominated by grasses and forbs and pinyon-juniper woodlands. When snow was present in the meadow, the flock spent 60% of its time in the pinyon-juniper woodlands where snow seldom covered the ground .
In the fall and winter, pinyon jays have been noted eating Gambel oak (Quercus gambelii)
acorns in Gambel oak communities in New Mexico, Utah, and Arizona .
Predation can be high for pinyon jays ; however, flocking, colonial nesting, and mobbing may deter predators [10,36,89]. In a study by Balda and Bateman , near Flagstaff, Arizona, 4-12 pinyon jays of a flock acted as sentinels, positioned at a high vantage point in a tree, waiting silently for an intruder while the flock was feeding. If an intruder approached, a warning call caused the flock to cease feeding and hide in the trees.
Pinyon jays have been seen mobbing great horned owls (Bubo virginianus) [10,88], sharp-shinned hawks (Accipiter striatus), Cooper's hawks (A. cooperii), red-tailed hawks (Buteo jamaicensis) , and common gray foxes (Urocyon cinereoargenteus) [10,88].
In a study conducted by Marzluff  in Flagstaff, Arizona, 122 pinyon jays nests were located and studied between 1981-1986. The percentages of identified predation events on pinyon jays were: ravens and crows (Corvus spp.) 76.2%; Steller's jays, Abert's squirrels (Sciurus aberti), and rock squirrels (Spermophilus variegatus) 18.0%; ground predators including snakes (Squamata), gray foxes, and domestic cats (Felis silvestris) 4.1%; and accipiters 1.6% . Mexican spotted owls (Strix occidentalis lucida) have also been seen consuming pinyon jays [120,127].
Incubating females are sometimes pulled from their nests at night . Female pinyon jays may be
vulnerable to nocturnal and diurnal predators because they are extremely reluctant to leave their
nests. Because pinyon jays breed in loose colonies, a predator attuned to finding nests could
potentially specialize on incubating or brooding females .
Pinyon-juniper woodlands: Due to the mutualistic relationship between the pinyon pine and the pinyon jay, "their interaction needs to be conserved" [56,105]. The singleleaf pinyon and Colorado pinyon do not produce cones until 35 years, and 25 years of age respectively. Therefore, the general recommendation for the preservation of pinyon jay populations is to manage for large, mature, cone-bearing trees [31,77,100] and preserve pinyon-juniper woodlands [1,34,77,100], as well as other habitats utilized by the pinyon jay [10,80,112,132].
Arizona Partners in Flight  recommends maintaining a stable or increasing population trend of pinyon jays throughout pinyon-juniper woodlands in the Colorado Plateau and Mogollon Rim physiographic regions. Other recommendations include: maintaining extensive stands of cone-bearing pinyon trees; identifying and retaining traditional home ranges; determining how many mature stands of pinyon-juniper stands exist; encouraging small-scale forest openings to reduce erosion in dense, mature stands; using appropriate livestock and/or wild ungulate stocking rates to promote grass and herbaceous growth; and considering common raven (C. corax) control if their increased numbers are affecting pinyon jay nest success. Additional information about the research and outreach needs for the pinyon jay can be found in the Arizona Partners in Flight Bird Conservation Plan.
Colorado Partners in Flight  suggests managing for large and old age-class pinyon pine trees for high seed production. Maintaining or increasing pinyon jay distribution and abundance is also recommended.
New Mexico Partners in Flight  lists the pinyon jay as a "high responsibility" species that requires large stands of mature pinyon pine and ponderosa pine trees covering extensive areas for foraging. For optimal habitat conditions, they recommend in areas where pinyon-juniper species are dominant, creating or maintaining 6 contiguous nonfragmented blocks of 500 acres (202.3 ha) each within 5,000 acre (2,023 ha) blocks.
According to the Cornell Lab of Ornithology , pinyon jay populations are declining due to the destruction of pinyon-juniper woodlands for grazing and changes in the fire regime.
Balda and Bateman  recommend that, to preserve pinyon jay populations, patches of pinyon-juniper and pure pinyon pine habitats be a minimum of 7 square miles (18 km˛).
In a study by Albert and others , the number of occurrences of pinyon jays decreased in thinned pinyon-juniper woodlands compared to control plots. In the pinyon-juniper woodland, Paulin and others  recommend a landscape mosaic that intersperses patches of cover for birds with openings for browsing and foraging.
Due to their dependence on mature, cone-bearing pinyon trees, pinyon jays may be negatively affected by the removal of trees for livestock in pinyon-juniper woodlands .
In a study by Goguen and Mathews  in northeastern New Mexico, the mean number of detections of pinyon jays was not significantly different (P= 0.93) in moderate, 3-season cattle-grazed areas versus ungrazed areas in pinyon-juniper woodlands :
|Treatment||Mean number of detections||Standard error|
Gambel oak: In Gambel oak woodlands of north-central Utah, the pinyon jay is a local transient species from adjacent habitats [62,85]. Pinyon jays use these woodlands in the fall and winter to forage on Gambel oak acorns. The proximity of Gambel oak woodlands to urban centers may cause the pinyon jay to experience substantial habitat loss and fragmentation in the near future. Leidolf and others  recommend that in order to maintain viable bird populations in Gambel oak habitat, federal and state land managers should consider nongame bird populations in their management plans. A recommendation for more research to be conducted on the response of birds to specific management actions such as prescribed burning, grazing, and cutting is also suggested.
Ponderosa pine: From 1911 to 1961, the population of pinyon jays in ponderosa pine forests of the southwestern United States decreased. This may be related to logging, fire exclusion, hunting, grazing, and herbicide and pesticide use. Canopy foragers, such as the pinyon jay, have been affected the most .
Pinyon jays may or may not benefit from livestock grazing in ponderosa pine habitat in the southwestern United States. The degree to which livestock grazing affects birds depends on several factors including: 1) number of animals grazing in an area; 2) timing of grazing; and 3) type of grazing system used . Habitat changes occur as grazing increases , affecting birds . Grazing generally leads to an increase in the density of ponderosa pine due to less competition of seedlings with understory vegetation . Since pinyon jays prefer open ponderosa pine habitats, they may be negatively affected . However, grazing may benefit pinyon jays because the increased density of trees such as ponderosa pine, oak (Quercus spp.), juniper, and pinyon provide more food sources .
Sagebrush: To improve most bird and animal species populations in big sagebrush (Artemisia tridentata) habitat, Welch  recommends that in areas where the sagebrush canopy exceeds 20%, sagebrush not be thinned or killed.
Other habitats: In 1981 and 1982, Medin and others  collected bird census data in several habitat types near and on Wheeler Peak in east-central Nevada along an elevational gradient of 5,250-11,400 feet (1,600-3,475 m). Twenty years later, Woodyard and others  recensused 6 of his 11 plots to determine how bird populations changed over time. The pinyon jay population decreased in 3 of the 4 of the habitat types from 1982 to 2002 :
Mean number of birds/10 visits
|Wyoming big sagebrush (A.t. ssp. wyomingensis)||0.1||1.0|
|Mountain big sagebrush (A.t. ssp. vaseyana)||0.3||0.0|
Total number of birds sighted in 70 censuses
|Rocky Mountain bristlecone pine||104||34|
Due to the importance of the pinyon [56,72,75,83,87,105] and ponderosa pine [10,41,49,72] to pinyon jays, the fire regimes for pinyon-juniper woodlands and ponderosa pine forests of the western United States will be focused upon in this section.
Pinyon-juniper woodlands: Prior to European settlement, pinyon-juniper woodlands occupied less than 7,413,000 acres (3,000,000 ha) in the Intermountain West and fire was the most common natural disturbance. Overall, fire is relatively uncommon in pinyon-juniper woodlands due to lack of fuels [53,116]. Fire regimes in this habitat were a mixture of surface and crown fires, depending on site productivity [57,58]. In open stands dominated by grass, fire intervals were 10 years or less [55,58]. Productive sites with many trees experienced patchy fires occurring at intervals of 10 to 50 years. In very densely wooded areas, crown fires may have occurred every 200 to 300 years [55,58].
Following European settlement, pinyon-juniper woodlands expanded into large portions of the southwestern United States previously occupied by grasslands [51,66]. As of 2005, pinyon-juniper woodlands occupy over 74,130,000 acres (30,000,000 ha) , a 10-fold increase since European settlement. This is due to livestock grazing [54,55,66,97,104,109,111], which reduces fine fuels, and the resulting decrease in fire frequencies [66,97,104,109,111]. Climate change and invasive plant species have also altered the fire regime in pinyon-juniper woodlands . For more details about the fire regimes in pinyon-juniper woodlands, see Colorado pinyon and singleleaf pinyon.
Because the fire regime in pinyon-juniper woodlands has changed from a mixture of surface and crown fires to more consistent high-severity, stand-replacement burns, bird species such as the pinyon jay are likely to be negatively affected due to their requirement for live, mature trees [99,113].
Most pinyon seeds cached by pinyon jays have a "reasonable" probability of surviving fire depending on the microhabitat of the cache . Undershrub and tree microhabitats experience higher soil temperatures during a fire than sparsely vegetated sites , and seeds buried in these areas would be expected to experience the highest seed mortality . In the Sheeprock Mountain Range within the Vernon division of the Wasatch National Forest in Utah, singleleaf pinyon seedlings appeared 22 years following a fire of unknown severity and did not dominate the site until after 70-80 years .
Pinyon jay populations may respond positively or negatively to fire. The response of wildlife populations to prescribed burning in pinyon-juniper woodlands was studied by Mason  in the White River area of the Humboldt National Forest, Nevada. The project was divided into 4 separate but interrelated subdivisions. Twelve burns were conducted during the spring and fall of 1974 and 1975, and ranged in size between 2 and 60 acres (0.8-24.3 ha). A total of 155 bird transects were run in 1974 and 1975. The mean numbers and total numbers of pinyon jays per transect were highest in unburned areas :
|Mean no. birds/transect||0.6||1.5||0.4||0.7||0.1|
|Total no. birds/transect||11||29||16||32||5|
In a similar study project by Mason , the response of wildlife populations to prescribed burning in pinyon-juniper woodlands was examined in the White Pine Ranger District of the Humboldt National Forest, Nevada. Details about the severity and time of year that the prescribed burn was conducted were not given. A total of 150 transects were run in 1974 and 1975, with 47% in burned areas, 43% in unburned areas and 10% in ecotone areas. The average number of all bird species sighted per transect was highest in burned areas. Prescribed burning in patches increased the density of all wildlife species due to the availability of a variety of habitat types throughout the year.
Following numerous fires across the western United States in 2002, Project Feeder Watch participants reported changes in the abundance of birds, including the pinyon jay. More pinyon jays were seen at residential bird feeders than in previous years. In Utah, following a 20,000 acre (8,094 ha) severe fire, pinyon jays numbering as many 160 at a time showed up at residential bird feeders for the first time in 30 years, indicating that they were leaving their native habitat in search of supplemental food at feeding stations .
Ponderosa pine forests: Ponderosa pine forests in the southwestern United States have been used by humans for at least 12,000 years, and frequent low-intensity fires were part of these forests' evolutionary history . Logging, grazing, fire suppression, and climate change have caused a general decline of these forests for the past 150 years [106,112]. From 1850 to 1900, low-intensity fires occurred at intervals of 2 to 12 years. According to Covington and Moore , fire suppression in the past 100 years has caused "decreased decomposition rates, stagnated nutrient cycles, eruption of insects and diseases, ecosystem simplification, increased vertical fuel continuity due to dense sapling and pole patches, higher severity and destructive potential of wildfire, decreased stream flow and on-site water balance, less wildlife habitat for species dependent of herbaceous vegetation, and greater canopy closure and landscape homogeneity." For more details about the fire regimes in ponderosa pine forests, see interior ponderosa pine, Pacific ponderosa pine and Arizona pine.
Three years following the 1996 Horseshoe and Hochderffer wildfires in ponderosa pine habitat in the Coconino National Forest in northern Arizona, bird counts were performed during the breeding and nonbreeding season. Details about the severity of the fire and time of year that the fire occurred were not given. The number of pinyon jays was greatest on severely burned areas during the nonbreeding season. The reason for this response was not discussed :
|Number of birds|
|Breeding season||Nonbreeding season|
Fire regimes: The following table provides fire return intervals for plant communities and ecosystems where pinyon jay is important. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes".
|Community or Ecosystem||Dominant Species||Fire Return Interval Range (years)|
|sagebrush steppe||Artemisia tridentata/Pseudoroegneria spicata||20-70 |
|basin big sagebrush||Artemisia tridentata var. tridentata||12-43 |
|mountain big sagebrush||Artemisia tridentata var. vaseyana||15-40 [5,27,96]|
|Wyoming big sagebrush||Artemisia tridentata var. wyomingensis||10-70 (x=40) [128,136]|
|blackbrush||Coleogyne ramosissima||<35 to <100|
|juniper-oak savanna||Juniperus ashei-Quercus virginiana||<35|
|western juniper||Juniperus occidentalis||20-70|
|Rocky Mountain juniper||Juniperus scopulorum||<35 |
|western larch||Larix occidentalis||25-350 [4,16,37]|
|Engelmann spruce-subalpine fir||Picea engelmannii-Abies lasiocarpa||35 to >200|
|blue spruce*||Picea pungens||35-200 |
|pinyon-juniper||Pinus-Juniperus spp.||<35 |
|Rocky Mountain bristlecone pine||P. aristata||9-55 [39,40]|
|Mexican pinyon||Pinus cembroides||20-70 [98,122]|
|Rocky Mountain lodgepole pine*||Pinus contorta var. latifolia||25-340 [15,16,123]|
|Sierra lodgepole pine*||Pinus contorta var. murrayana||35-200 |
|Colorado pinyon||Pinus edulis||10-400+ [46,58,69,103]|
|Pacific ponderosa pine*||Pinus ponderosa var. ponderosa||1-47 |
|interior ponderosa pine*||Pinus ponderosa var. scopulorum||2-30 [3,8,78]|
|Arizona pine||Pinus ponderosa var. arizonica||2-15 [8,33,114]|
|quaking aspen (west of the Great Plains)||Populus tremuloides||7-120 [3,59,95]|
|Rocky Mountain Douglas-fir*||Pseudotsuga menziesii var. glauca||25-100 [3,5,6]|
|oak-juniper woodland (Southwest)||Quercus-Juniperus spp.||<35 to <200 |
|live oak||Quercus virginiana||10 to<100 |
|redwood||Sequoia sempervirens||5-200 [3,45,120]|
For more detailed suggestions on the fire management of trees important to the pinyon jay in pinyon-juniper woodlands, and in ponderosa pine forests, see Colorado pinyon, singleleaf pinyon, Utah juniper, interior ponderosa pine, Pacific ponderosa pine, and Arizona pine.
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