Take a look at this video:
If a word is spelled correctly, the pigeon has been taught to peck at the word. If it's spelled incorrectly, the pigeon is supposed to peck at the star. When it gets it right, the machine hands it some food.
A group of researchers from New Zealand were able to train four pigeons to consistently — with 70 percent accuracy — recognize dozens of words. The smartest pigeon learned about 60 words that it could distinguish from about 1,000 nonwords.