Great picture; you must have been sleepless last night, just waiting for the right moment. Looks like it might be dry in your area, for a deer to risk coming into water in the bird bath.
Then again, Animals will do what animals do. We have several 'clear' water pans around for the seven cats to drink out of for fresh water...and they go down to drink out of the small child's wadding pool that the ducks have gotten all dirty washing their beaks off and swining into the pool water.