The pinyon jay (Gymnorhinus cyanocephalus ) is a jay between the North American blue jay and the Eurasian jay in size. The voice is described as a rhythmic krawk-kraw-krawk repeated two or three times. It is the only member of the genus Gymnorhinus. Its overall proportions are very nutcracker-like and indeed this can be seen as convergent evolution as both birds fill similar ecological niches. The pinyon jay is a bluish-grey coloured bird with deeper head colouring and whitish throat with black bill, legs and feet.
They are highly social, often forming very large flocks of 250 or more birds, and several birds always seem to act as sentries for the flock, watching out for predators while their companions are feeding. The seed of the pinyon pine is the staple food but they supplement their diet with fruits and berries. Insects of many types are also eaten and sometimes caught with their feet. The nest is always part of a colony but there is never more than one nest in a tree. Sometimes the colony can cover quite extensive areas with a single nest in each tree (usually juniper, live oak or pine). There are usually 3–4 eggs laid, quite early in the season. Incubation is usually 16 days. The male bird normally brings food near to the nest, and the female flies to him to receive it and take back to the nest to feed the chicks that fledge around 3 weeks later. Young are normally fed only by their parents, but once they reach the near-fledging size they can sometimes receive a meal from any passing member of the colony, which can continue for some time after leaving the nest.
The pinyon jay was first collected, recorded, and first described as a species from a specimen shot along the Maria River in Northern Montana during the Prince Maximilian of Wied-Neuwied Expedition to the Interior of North America in 1833. A historical marker at LaHood Park on the Jefferson river in Montana, however, claims that the first pinyon jay known to science was seen and described by the Lewis and Clark expedition at their campsite on this site on August 1, 1805. This species occurs in western North America from central Oregon to northern Baja California and eastward as far as western Oklahoma, though it wanders further afield outside the breeding season. It lives in foothills where the pinyon pines Pinus edulis and Pinus monophylla occur.
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DiurnalDiurnal animals are active during the daytime, with a period of sleeping or other inactivity at night. The timing of activity by an animal depends ...
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TerrestrialTerrestrial animals are animals that live predominantly or entirely on land (e.g., cats, ants, snails), as compared with aquatic animals, which liv...
Oviparous animals are female animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive...
Monogamy is a form of relationship in which both the male and the female has only one partner. This pair may cohabitate in an area or territory for...
Flocking birds are those that tend to gather to forage or travel collectively. Avian flocks are typically associated with migration. Flocking also ...
Highly social animals are those which are highly interactive with other members of their species. They live in large groups, nest in colonies, and ...
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Not a migrantAnimals that do not make seasonal movements and stay in their native home ranges all year round are called not migrants or residents.
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starts withPinyon jays are residents from central Oregon to western South Dakota, south to northern Baja California, northwestern and east-central Arizona, central New Mexico, and western Oklahoma. They winter throughout their breeding range and irregularly from southern Washington to northwestern Montana, and south to Mexico and central Texas. When pinyon seed crops are poor, pinyon jays may wander to central Washington, northwestern Oregon, northern Idaho, northwestern Montana, throughout the Great Basin, Nebraska, Kansas, central-western and southwestern California, southeastern Arizona, central Texas, and northern Chihuahua. The pinyon jay is casual in Iowa and a sight report exists in Saskatchewan.
The pinyon jay is a permanent resident of pinyon-juniper (Pinus-Juniperus spp.) woodlands and low-elevation ponderosa pine (Pinus ponderosa ) forests in the southwestern United States. Pinyon-juniper woodlands are composed primarily of Colorado pinyon (P. edulis ) and Utah juniper (J. osteosperma ) 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 ). 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 article, "pinyon" refers to both Colorado pinyon and singleleaf pinyon, and "ponderosa pine" refers to interior ponderosa pine and Arizona pine unless otherwise specified.
Pinyon jays prefer pinyon-juniper woodlands, and ponderosa pine forests. They interact in a mutual relationship with the pinyon. Pinyon trees provide pinyon jays with food, nesting and roosting sites, and breeding stimuli. Pinyon jays influence seed dispersal, establishment, 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 an interval of 4 to 7 years, 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, perhaps to counteract seed predation. Bumper seed crops of the Colorado pinyon are episodic and are probably linked to favorable climatic conditions.
Singleleaf pinyon may not produce cones until 35 years of age with a 2- to the 7-year interval between cone production years. The maximum seed production occurs when trees are 75 to 100 years old.
Pinyon jays are noisy groups, though they may form large of more than 250 to 500 members as they are watching out for predators while their companions are feeding seeds. They spend most of their time searching for seeds to be eaten on the spot, hide in the ground, or store in a tree crevice to eat later. They utilize pinyon, western juniper and ponderosa pine 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. Pinyon seeds are heavy and wingless, and not suited for wind dissemination. Their dispersal requires birds, animals, and humans. 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.
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 such as caterpillar (Lepidoptera) larvae, beetles (Coleoptera), grasshoppers (Orthoptera), and ants (Hymenoptera) make up a large portion of their diet. Spiders (Araneae) are commonly eaten, and cultivated grains including corn, sorghum, beans, barley, oats, and wheat are consumed during winter months. Pinyon jays have also been noted ingesting soil around salt blocks for cattle.
Nestlings eat insects, soft plants, and pinyon seeds when they are plentiful.
Pinyon jays form flocks of 50 to more than 500 and occasionally thousands of individuals, that begin to forage together in late August. Flocking may be an adaptive strategy to increase search efficiency and reduce predation. 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 with 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 the sound produced by clicking seeds with their bills. Pinyon jays can hold up to 43 ponderosa pine seeds and 56 pinyon seeds in their expandable esophagus.
Pinyon jays forage mainly on pinyon seeds in late summer and ponderosa pine seeds in fall and early winter. 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 the 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.
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.
Pinyon jays appear to form perennial, monogamous pair bonds 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 and ponderosa pine forests 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. 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. 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, 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.
A flock of 250 pinyon jays was studied in a ponderosa pine forest and adjacent pinyon-juniper woodland for 2.5 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 the 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 occurs from late February to April. 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". 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 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, one study 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.
Females typically incubate 3 to 5 eggs. 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. 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.
The pinyon jay is listed as a species of Vulnerable by the International Union for Conservation of Nature. Between 1859 and 1880, it is estimated to 400,000 and 525,000 of pinyon woodlands was mostly used for mine construction and production of the charcoal. Between 1950 and 1964, an estimated 3 million acres of pinyon woodlands were used, this led to millions of pinyon jays that may have died. These impacts and predictions have increased concern over the future of the vulnerability of pinyon jays. Across the West, thinning, fire and chemical treatment of pinyon-juniper woodlands have increasingly been used to reduce potential wildfire risk on them or to improve biodiversity or ecological condition, this led to pinyon jays stopped nesting within the thinned areas of a traditional nesting colony. A human development such as oil and gas wells may affect pinyon jays as they tend to avoid nesting near the developments, and also an unknown decline of insect populations worldwide.
Social animals are those animals that interact highly with other animals, usually of their own species (conspecifics), to the point of having a rec...