Just like bluebirds, Blue Jays have no blue pigments in their feathers. Instead, each feather barb has a thin layer of cells that absorb all wavelengths of color except blue. Only the blue wavelength is reflected and scattered, resulting in their blue appearance to our eyes.
Blue Jays are often chastised for their known practice of eating eggs and nestlings of other birds. But extensive research has proven this to be a very rare occurrence, with only 1% of the study population showing any evidence of this behavior.
Blue Jays are known to migrate, but the phenomenon is not well understood by scientists. Research has shown that some individuals will migrate south during some years and choose to stay in the north during others. Why they do this is still one of nature's mysteries.
It is estimated that only about 20% of the population of Blue Jays migrate, even in the northern parts of its range.
Many migrating Blue Jays reach their wintering grounds after natural food crops, such as acorns, may have already peaked. Whether they still cache a winter food supply is unknown at this time. Birdfeeders may play an important role for some of these birds.
Most migratory flights by Blue Jays begin about an hour after sunrise and cease by noon. The average migrating flock contains 10-30 birds.
Peanuts in the shell are a favorite among Blue Jays. Watch your feeder to see if you can observe them weighing peanuts to find the heaviest peanut.
Blue Jays eating a diet of only acorns quickly start to lose body mass, unless those nuts are full of protein-rich weevils or supplemented with other sources of insect protein.
Blue Jays mainly select undamaged nuts to bury; research has shown that only 10% of the acorns they cache are not viable seeds.
Blue Jays will bury seeds up to 2 miles from their original source which is a record for any bird. This behavior has greatly helped with the range expansion of many oak species.
The rapid northward dispersal of oaks after the Ice Age may have resulted from the northern transport of acorns by jays.
Due to the jay's habit of burying acorns over a wide area, 11 species of oak trees have become dependent on Jays for the dispersal of their acorns.
Due to Steller's Jay's habitat of burying pine nuts, several species of pine trees have become partially dependent on them for the dispersal of their seeds.
Research studies have recorded Blue Jays making over 1,000 trips per day when hiding food.
In one research study, 50 Blue Jays were observed selecting and caching 150,000 acorns over a period of 28 days. Each bird cached a total of 3,000 acorns by selecting and hiding an average of 107 acorns per day.
In one research study, Blue Jays were observed storing over 2,000 beech tree nuts in one month.
A Blue Jay was observed packing over 100 sunflower seeds into it's gullet during just one visit to a feeder.
The Blue Jay is a talented mimic; its version of a Red-shoulder Hawk's call can fool even the most experienced birder.
An old folktale says that the Blue Jay was yoked to a plow by a sparrow and the mark it left behind is still visible today on the Blue Jay's neck and chest.
Jays will cache seeds and nuts to retrieve later, and make repeated trips to feeders to gather food and hide it in a safe spot.
The Gray Jay stores food items by using its sticky saliva to glue them to branches high up in trees. This food is always available, even during the deepest snow periods.
Mated pairs of Gray Jays live most of their lives in a territory of less than 200 acres in size and rarely leave it.
The Gray Jay is one of the few species, other than raptors, known to carry food items with its feet while in flight.
The name jay has its possible origins from the Latin "gaius" meaning gay or merry.
The species name cristata originates from the Latin word "crista", meaning crested.
Look for sentinels in scrub-jay flocks foraging in your yard. If the guards spot a threat, the whole group may join in a mobbing behavior to protect themselves.
Scrub-Jays bury many more acorns than they consume, thus helping to renew many species of oak trees.
The Blue Jay and Steller's Jay occasionally interbreed and produce hybrids.
The Steller's Jay is official bird of the province of British Columbia.
The Western Scrub-Jay and Mule Deer have a very cooperative relationship. The deer allow the jays to land on their bodies and jump from place in search of parasites on which to feed.
Western Scrub-Jays have been known to cache up to 6,000 pine seeds or 5,000 acorns in single autumn.
The Florida Scrub-Jay can become very tame around people and will even land on them in search of a tasty hand-out of food.
Florida Scrub-Jays often help raise the young of others in the flock.
The Pinyon Jay's favorite food of pine nuts is the same seed that people often enjoy as the snack food purchased under the same name.
Like most jays, Pinyon Jays store hidden caches of food, but unlike other jays, both members of a mated pair work together to hide the food items and thus, both of them know the location of their hidden supply of food.
Unlike other jays, the Pinyon Jay has no feathers at the base of its bill. This allows it to search deep into pine cones for seeds without soiling its feathers with sticky pine sap.
In years when pine cone crops fail, Pinyon Jays will engage in an irruptive migration, leaving their permanent home territories and moving great distances in search of food.
Pinyon Jays live in permanent social groups that may contain over 500 individuals.
The following are longevity records for some banded jays in the wild: