Red-headed Woodpecker
Turkey Run State Park

I have heard two opinions regarding the sexual differentiation of Red-headed Woodpeckers. The first is that the species is sexually monomorphic, meaning that the sexes are not different. The second opinion I have heard is that the males have a more distinct black ring around their necks. That would mean that this is a male bird. Not sure which is true, although most bird books nowadays state that these birds are in fact sexually monomprphic.