How do birds find worms? #Video

How do birds like the American robin, killdeer and European starling find worms? What senses do they use, and how are they able to pull a worm out in one attempt? I discuss some of the research and some of my own observations on American robins and killdeer. Sometimes when presenting research in a video, the answer is that we don't quite know why or how. A research study says one thing, only to have different or contradicting evidence in another study years later. Also, what senses a bird uses to find worms may vary from one species to another, as I noticed with the killdeer (no head cock to the side like the American robin). Currently, the research has shown that we know some of the answer, but not all of it, and that's where our own observations play an important role. ---