Getting your dog to stop howling at sirens is a definite challenge. The sporadic nature of sirens -- plus the fact that you probably aren't home with your dog all the time to discipline him -- can make teaching him to be quiet when a siren sounds problematic.
Step 1
Record the sound of sirens. This allows you to desensitize your dog to the noise on your own terms. Check with your local emergency services department to see if they will provide you with a recording if you cannot get one on your own, either in real time or digitally.
Step 2
Play the recording on a regular basis. Do not make a big deal about it, and don't stand by the device while you are playing it.
Step 3
Tell your dog "hush" or "quiet" when he starts to howl. Most dogs will look at you and stop howling at this point. If he ignores you, you may have to be more insistent. One way to discipline for howling is to give a quick squirt with a water bottle when you give the command to be quiet. Always give him the chance to be quiet on a verbal command first.
Step 4
Enforce the quiet command by continuing exposure to the siren recording for short periods of time several times a day. The combination of your correction for howling, plus regular exposure to the sound, will cause him eventually to ignore the sound of the siren.
