In the Middle Ages, Christians shared oral stories of Jesus through stain glass images.
Across the Southwest about the same time, Ancestral Puebloans, with no written language, relied on imagery to pass down their traditions.
"People remember pictures," said archaeologist Sally J. Cole, author of "Legacy of Stone: Rock Art of the Colorado Plateau and Four Corners Region."
Before a crowd of about 50 people, Cole spoke as part of the Four Corners Lecture Series at Mesa Verde National Park last week. Her hourlong talk centered on bird figures found in petroglyphs and paintings of the Ancestral Pueblo tradition.
Cole's lecture included photos of petroglyphs found in Colorado, Utah, Arizona and New Mexico - mating birds, mythical birds, polka dot birds, human figures with ducks for heads, flying turkeys, turkeys, whispering birds, love birds, macaws with curved beaks and long tails, eagles spitting out seeds and even a horned mythical bird or monster raven.
Asked why the Native ancestors would depict a bird to serve as the head atop human figures, Cole speculated the images might have represented a crown.
Cole added that the petroglyphs were more than artistic expressions - they were used in place of a written language to pass down oral traditions.
"When it started, art was a way to talk, to share your culture, your society and your traditions," she said.
"A picture is worth a thousand words, right?" she posed. "It's all about education."
In the Four Corners, the Anasazi depicted at least 45 species of birds. Ducks, turkeys and eagles were the most common, but quails, swallows, magpies and bats were also carved into cliffs.
Cole also shared images of birds on pottery and wood. A mural portrayed feathers attached to a tree-like figure.
"The feathers represent prayers," she said. "Feathers were essential to communicate with the spirits."
Cole is adjunct faculty member of the Department of Anthropology at Fort Lewis College and research associate at the museum of Natural History.