Thank you all for your responses. I received 19 responses and almost every one said "DEER"! I was so surprised. I want to clarify that I did not mean in my yard... although some of my tulips did not come up this year. I was referring to the gorgeous flower beds at the entrance to the park. Attached is a spectacular picture from 2006 to compare-- this year they are much more sparse and I see that a lot of them look as though someone had cut them down.