The turkey was encountered by the Spanish conquistadors when they conquered the Aztecs in Mexico. The Aztecs had domesticated the bird for food and the Spanish brought it back to Spain.
In Spain and throughout Europe, it was bred and re-bred into the forerunner of the domestic turkey. It evolved into a very different bird from the original "wild turkey". The pilgrims brought it back to North America, and started the custom of eating it at Thanksgiving.
Since that time the domesticated turkey has been aggressively bred and hybridized even more, primarily to have more and more meat. These days, it can no longer fly, and has become what winds up on our plates each Thanksgiving.