The Northern Flicker has two forms, the Eastern "yellow-shafted Flicker" and the western "Red-shafted Flicker". Examples of both forms are shown below.

Northern Flickers are the only woodpeckers to feed on the ground. Their primary food is insects (mainly ants), although they do eat fruits, berries, seeds and nuts.

I have seen Northern Flickers throughout California and recently in Michigan and Illinois.