During a new roof installation, some Florida roofers ran into a surprise when they were tearing up the old one. Make sure that checking your roof is a routine part of maintenance.
Bats have an undeservedly bad reputation in public lore (well, except for Batman) but they are important little critters that keep the insect population down, have a role in pollination and seed distribution, and play other important ecological functions. Because of this, they are a protected species under Massachusetts law, and most other state laws too.
The Massachusetts Wildlife Department offers a useful Homeowner's Guide to Bats that offers information on what to do if a bat gets in your house, signs that a bat colony might be inhabiting your attic, advice for how to get rid of a bat colony that has adopted your home as their own, and other bat-related tips and pointers.
One other note about the video on a different topic from the bats: If you have roofers working on your house, make sure that they use safety harnesses or some type of fall protection! While a work injury would typically fall under workers' comp, as a homeowner, you don't want to take any chances.