I know it's a recurring phenomenon, but now that a featherless-headed Cardinal is frequenting my feeders, can someone enlighten me why this occurs, how long the condition persist, and whether it affects the general health or reproductive capabilities of the bird. In all other respects, this bird carries on as if he is as beautifully plumaged as the other Cardinals he feeds with. Thank you. Warbler migration is underway. I have had Canada, Worm-eating, and Black-and-White Warblers and Redstart in my yard over the past few days. Ralph Wall Great Falls, Va.