[Maine-birds] mystery dove

I have received a couple of photos of doves that were seen by my cousin visiting in Oakland ,Ca. this past week. One has a bump on the forehead and slightly different plumage. They were seen on a breakwater by the ocean-is it in fact a mourning dove with an anatomical anomaly or something different? Pics are posted on maine birds group on flickr-cannot get link to work!  Thanks, Sharon in West Kennebunk