Was your dog recently separated from its litter?
Does your dog howls the most when you are separated?
Do you pay little attention to your dog?
Does your dog shows any signs of injury or illness?
Is there a source of the sound that can be irritating to your dog nearby?
Are there any other dogs in the neighborhood that howl as much as your dog?
Dogs are pack animals, and they have a strong sense of separation anxiety. When they feel separated from their pack, or when any member from their pack is missing, they trigger a howl.
Dogs are deeply attached to their owners and families. When they feel a sense of separation, they howl. Normally, when you take your dog to a new place, he or she will enjoy the new abode as long as you are around. But once you leave your dog alone, he or she will feel separation anxiety and may start howling.
When dogs lack physical exercise or feel nervous, they may need even more of your attention. If their needs are not being fulfilled, they can develop behavioral problems. Such behaviors may include a repetitious mild howl, which is your dog's natural way of requesting your attention.
Sometimes your dog might howl due to illness: something could be physically wrong and he or she could be suffering from internal pain. So if your dog is howling consistently, then you need to make sure he or she is not sick and check for any physical injuries. If the dog does have any visible injuries, then you need to visit your veterinarian.
If your dog is feeling annoyed or sad, he or she may howl. For some dogs, music (especially instruments like the mouth organ) is an irritating noise, and if they've been hearing it consistently, it may trigger a howl. Some other sounds can annoy them like alarm clocks, electronic beeps, and sirens.
If you make a howling sound, then it’s possible that your dog will also start howling, or when one dog starts howling, then other dogs will also start howling. It may be a natural pattern for dogs to respond.
A wolf's howl is its natural way of vocally communicating in the wild. Wolves howl to send a message to their separated pack members, informing them about their presence and current location—this method helps them find each other. Dogs have inherited this behavior from their ancestors.
https://pethelpful.com/dogs/Why-do-dogs-howl-at-night

Sreten null
Hi! I’m Sreten Filipović. I graduated from the Faculty of Agriculture at the University of Belgrade, with a master's degree in Environmental Protection in Agricultural Systems. I’ve worked as a researcher at Finland's Natural Resources Institute (LUKE) on a project aimed at adapting south-western Finland to drought episodes. I founded a consulting agency in the field of environment and agriculture to help farmers who want to implement the principles of sustainability on their farms. I’m also a founding member of the nonprofit organization Ecogenesis from Belgrade whose main goal is non-formal education on the environment and ecology. In my spare time, I like to write blog posts about sustainability, the environment, animal farming, horticulture, and plant protection. I’ve also published several science-fiction short stories.
You can find me on LinkedIn at https://www.linkedin.com/in/sreten-filipovi%C4%87-515aa5158/