The older cows generally go into heat a couple weeks before the cows in good shape. Add to that the fact that there is no time that the bulls hormones are higher then right now, and early bugling can and does happen quite often, with a lull for a week or so.
Though it dos seem that everybody i'm talking to, from NM to Montana is hearing bugling bulls right now. Perhaps its just early!
The elkheaven guys are generally dead on, and they say that it will be early this year, but they were shooting for the peak to be around the 18th.
We'll see. Good luck and thanks for the report!