Lawn damage due to rabbits or Fairies?
Hi ! You are correct, I do not believe it is rabbits, either. While rabbits can cause damage and death to patches of your lawn, if you don't see rabbit "poop" in those circles, it is most likely you are battling necrotic ring spot. It is a perennial disease of some varieties of Kentucky bluegrass, which results in circular or donut-shaped patches of dead grass with a green "frog-eye" inside the patch of dead. It is a fungus which attacks and kills the roots and the crowns of the grass. The appearance will probably improve, going into fall, but will reappear in the mid-summer, because of the perennial nature of the disease. Good management practices such as: not overwatering and not over fertilizing your lawn with nitrogen, can help. Applying certain fungicides and sulfur amendments can help, as well. Sometimes, unfortunately, the ultimate solution is to remove the lawn and re-plant or re-sod with a resistant variety of bluegrass. At the top of my response I have copied the link to a CSU Extension Fact Sheet which is extremely helpful. It lists ways to manage the disease, along with fungicide products, and if all else fails, resistant varieties of Kentucky bluegrass that can be planted in place of the existing susceptible grass that you currently have.