deer might snort and or stomp their feet if they are alarmed.if it was close to the rut, i would say that it could have been a buck in towdemonstrating his tending grunt to her. and the rustling you might have seen / heard could have been him following the doe or her running away from him. but this is kinda a stumper. instead of him warning you, he could have been warning or just comunicating with another deer or deers in there, and they just probally moved on.