Backyard barking is often your dog's way of expressing his frustration with day-to-day life. The neighbor's dog won't scare off as he struts past your fenced-in yard and the letter carrier strolling to your front door are creatures your pup would love to chase because of his protective instincts for his home turf. But the fence blocks his way.

Dogs can also become habitual barkers to get your attention when they want to be played with or fed. Barking or howling can even be a vestige of your dog's wolf ancestry, a reminder of the days when howling brought the pack together. What he sees and hears outside the home is a carnival of stimulation that, in your absence and in his boredom or loneliness, leaves him with only barking as an outlet.

"If your dog is barking outside, he's not happy," says Katherine A. Houpt, VMD, Ph.D., director of Cornell University College of Veterinary Medicine's Behavior Clinic. "He's usually barking because of a territorial challenge."

Outdoor barking can be difficult to control. The alarm like protection that barking provides for owner and home is a big reason many people have a dog, so barking should not be totally eliminated. But the line is easily crossed from protective to just plain noisy, leaving you frustrated, your neighbors angry, and visitors and neighbors alike fearful of being bitten if they get too close. Left untrained and unrestrained, many dogs will bark more and more as time passes.

There are several techniques you can use to help eliminate excessive barking outdoors.

Does your dog really need to spend a lot of time outside, where his exposure to other animals, insects, and infectious agents is greater than it is indoors? If your dog is housebroken and has no chewing problem, Dr. Houpt recommends keeping him indoors most of the time. This will usually mean a healthier, happier, cleaner companion for you and less noise for your neighbors. However, you must be sure to provide your dog with plenty of exercise-through walks on-lead, playing in the yard when you are home, etc.

More plantings, a visually opaque privacy fence, or vinyl strips woven through your cyclone fence will reduce the visual and some of the aural stimulation your dog receives, and thus make him more secure and quieter when in the yard.

Regardless of your dog's indoor vs. outdoor time, you need to control his barking, whether you have a noisier breed such as a Terrier, Beagle, Sheltie, or Lhasa Apso, or a less vocal canine. He has to learn to "speak" on command or under appropriate circumstances, such as when a potential burglar is near or when a smoke detector goes off. But he needs to be quiet most other times. For instance, he must be forbidden to bark at children on bikes.

It is much easier to teach a pup than to reform an overzealous barker. Say, "What's that?" when you hear a strange noise outside or at the door. If the pup barks once, praise him and give him a treat or toy. The idea is to reward one or two woofs followed by silence. If he persists in barking, say "Shh!" quietly with your face close to his. That is enough punishment for most pups.

Do not say "No!" or anything else loudly because that can trigger a barking contest, with each or your "Nos" followed by one of his "Arfs!" An older dog may need firmer discipline, but the principle is the same. Say "Shh!" and then give a command such as "Down," since dogs are less likely to bark while lying down. This is known as counter-conditioning.

This method teaches the dog to do something incompatible with barking after his warning bark. He gets a food reward for obeying. To aid in training, you may consider using a halter collar, which tightens around his nose. A sharp pull of the lead when connected to such a collar is an effective reprimand and should be followed by a command to end the barking.

For dogs that are nearly hysterical barkers, give the "Shh!" command in a firm way, and then spray their faces with water. Again, immediately follow the silence with praise and a reward. Respond to every bark with a "Speak" or "Quiet" command until an unambiguous pattern is set. Although this can take time, the benefits far outweigh the effort.