Home owners unless you want someone else living with you that you may not be able to get rid of, by law, and then please cap your chimney.
I came across a vacant home that one of my buyers was thinking about purchasing, and I heard something in the basement. It was coming from an old oil heater vent that went in to the chimney. Not only was the top of the chimney not capped, but neither was where the oil furnace vent entered into the chimney.
When I took my flashlight and shined it into the hole, I couldn't see anything. But, when I shined my flashlight and took a picture, I saw all I needed to see. A family of birds had decided that was a good place to put a nest. There were signs that the birds had also made it in to the house, leaving who knows what kinds of diseases behind when they came in.
Here is the worst part about it, when my buyers said they wanted to buy the home, I told them they need to check with the city to see if they can get rid of the birds. They found out that they couldn't or they could get cited for disturbing a natural bird's nest. They would have to wait until the birds vacated on their own, then they could clean up the area and cap everything off. That could be months and they were not even allowed to cap off the inside of the home either.
I told the seller's agent what had happened, sent the pictures and the response from the city, and he passed it on to the seller, who was none too pleased to find out this news. The fine could be up to $1,000 per bird from what my buyer told me. Not sure I would want to test to see if the city was watching me after that.
Capping your chimney also can keep water out that can damage the bricks of old fireplaces, and keep yourchimney in good working order for many more years to come.
For more information on simple things that you can do to protect your home from wildlife moving in with you, please feel free to contact me anytime.