Walking Sticks are easily missed among the branches and twigs by their predators, is that because . . . Many examples can be given. The acorn woodpeckers of California seem to give thought to the future by storing away a food supply. They drill holes in trees and fit acorns into the holes. If the acorn crop fails, however, the birds store pebbles instead.
Many nests are marvels of skill.
But if a nest is damaged while it is being built, the bird is unable to repair it. The parents have to start over again from the beginning. Birds show the most apparent intelligence in meeting the problems of getting their food. A few birds make use of tools in a very human sense. Gulls and ravens break open shellfish by carrying them up to a height and dropping them down on rocks.