K9 Nose Work
Nose Work is fun activity based in the training of detection dogs and can be done by all dogs and their people.  It builds confidence and focus, and provides the dog with both mental and physical exercise.  No special equipment is needed and it can be trained at home. 
In the beginning, the dog will be searching for the odor of Birch.  You will be hooked from the moment you recognize that your dog is not only communicating that it has found the odor but is showing you exactly where it is.  Dogs love this work because they get a pay off upon finding the hide; the pay off is either high value food or toy.
When searching, the first indicator of recognizing the order will be a change of behavior in the dog when it is in the area of odor.  In the photo. note how Will is wrapping back to a box after catching the scent.
Each dog develops its own means of communicating to the handler where the odor is.  There is no right or wrong way of doing it; it only needs to be recognizable by the handler.    Some dogs will perform a sit or down by the odor; while other may indicate by placing their nose on the object containing the scent, as Kobi has done in this photo.
While still other will develop more flair in their communication style.  Here Will is indicating that he has located the odor by using his paw to smash the box containing the odor.
Both Will and Kobi have passed Odor Recognition Tests through NACSW.  https://www.nacsw.net/
Will has earned Novice Nosework Containers (NNC) title through United Nosework (soon to be transferred to United Kennel Club) http://www.unitednosework.com/Welcome.html