Where ever you roam across these United States, you're bound to see (and hear) a generally noisy bird with blue feathers - a Jay. If you're in the eastern U.S., it would likely be a Blue Jay (Cyanocitta cristata), crested, with black collar and necklace, white spotted wings and tail, blue above, grayish white below, with grayish white around the eyes and around the front of the neck.
Western Scrub-Jay (Aphelocoma californica)
In the western United States, you're more likely to see a Western Scrub-Jay, most notably missing the crest, but with blue head, wings and tail. Throat is streaked gray and white, bordered by bluish necklace. Thin white eyebrows and grayish back, along with a noisy chatter, complete the distinguishing characteristics.
Also common in the West, in mountainous pine forests from southern Alaska to Mexico, is Steller's Jay - so named, not because of its stellar blue feathers, but after the German naturalist Georg Wilhelm Steller who discovered them in 1741.
Other regional jays include the Florida Scrub-Jay, similar to the other scrub-jays but especially indigenous to Florida. If you're thinking about feeding them, you might first want to read what Wikipedia has to say about that:
"An inquisitive and intelligent species, the most striking attribute of the Florida Scrub Jay's behavior is its remarkable tameness. Scrub Jays show almost no fear of people and will even take peanuts from people's hands and lips, but it is illegal to feed a Florida scrub jay. It is detrimental to their health and even the overall survival of the species: Florida scrub jays that are frequently fed by people reproduce earlier in the year than those who are not fed, drastically reducing the survival rate for their offspring."
An apparent variant of the Western Scrub-Jay is the Utah Scrub-Jay. Although not listed as such in my field guide to western birds, it does seem to have noticeable variations in coloration from other scrub-jays, more closely resembling a Mexican Jay.
Mexican Jay (Aphelocoma ultramarina)
The difference in the Mexican Jay is its lack of crest (similar to scrub-jays), and its uniform blue above and grayish white underneath, with no other distinguishing markings. It is so named because it is mainly found in Mexico and southeastern Arizona.
Harder to find is the Pinyon Jay (Gymnorhinus cyanocephalus), native to semi-arid foothills of the West where pinyon pine and juniper grow. Its overall blue color is accented by a wedge-shaped bill and faint white streaks on the throat, and no crest. Unfortunately, no Dreamstime photos were found of this striking bird.
A bird in the Jay family that doesn't share the blue coloration is Clark's Nutcracker as it is gray with black wings and central tail feathers. It is found in coniferous mountain forests of the western US and Canada. It is named after William Clark, of Lewis and Clark, who explored and documented the American West from 1803 to 1805.
Although Dreamstime contributor Vincent Dale (thevinman) of Fort Saskatchewan, Canada, has labeled these three photos above as a Gray Jay, they are actually a Clark's Nutcracker. I hope "The Vin Man" has an opportunity to read this and make the necessary corrections to properly identify the images.
Another non-blue jay is the Gray Jay. It is distinguished by a white forehead, dark gray cap, short bill and dark gray wings. It is common to most of Canada and Alaska, as well as the Cascades and Rockies of the U.S. It is perhaps the boldest of the jays. An unabashed opportunist, it eats practically anything, including small rodents, invertebrates, the young and eggs of birds, berries, fruit, and human food scraps. It especially frequents campgrounds, where it will steal food right off your picnic plate while you're still eating it.
Other birds loosely associated with jays include blackbirds, ravens, magpies and larks. Appreciation goes to all those Dreamstime photographers who provided the jay photos.
Reference: Stoke's Field Guide to Birds - Western Region, Donald and Lillian Stokes, copyright 1996, published by Little, Brown and Company, ISBN 0316818100