random barking

Question
I have a six month old cairn terrier. For some reason, he's just started to start barking. Not a lot, but sometimes he just starts barking inside the house randomly at nothing ( or maybe he's smelled something or seeen something through the window). Most of the time he stops within 30 seconds. Should I do anything to correct this?

Answer
The dog may scent something, or even see something through your winodws (like falling leaves) that frightens or excites him.  The fact that he stops so suddenly makes me think he is responding to an isolated incident that suddenly, itself, stops (like falling leaves.)  There's no reason why a dog shouldn't be allowed to vocalize.  The bark is used as an alarm (among other things).  If you do not perceive a threat, tell him "quiet" and verbally praise him when he stops.  This will let him know that you are "on the job", will develop a signal "Quiet" for future use, and will help assuage any fear response he may be exhibiting.  You don't want a robot! that's why you have a dog, instead.  And you DO want your dog to bark on alarm (in the event there's something going on you should know about, like strangers at the door or on the property.)