page_title: Pinyon jay
section_title: Survival
hierarchical_section_title: Pinyon jay / Behavior / Survival
caption_attribution_description: ebird.org/ebird/view/checklist?subID=S21054294
context_page_description: The pinyon jay 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. There are usually 3–4 eggs laid, quite early in the season. Incubation is usually 16 days.
context_section_description: 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 the 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 the 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 the 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.
caption: Pinyon jay in flight
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