Blue jays are pretty common. We see them all the time, and yet, they still have mysteries to share with us. Blue jays are also known as the "engineers of the forest." Their diet consists of acorns and beech nuts and they take these seeds to new areas and cache, or bury, their food. Sometimes they forget to come back to get these stored nuts and seeds allowing them to grow. The birds are planting new trees and expanding the forest.