I read the book with the kids for enjoyment first. Then I read looking for bat facts and bird facts and things that are the same and different.
The kids read in groups of two or three depending on the strength and grade of the readers in your room. I start a venn diagram graphic organizer with the whole class. Then the kids read looking for information to add the the venn diagram. I give the kids sticky notes so the kids can put a sticky note where they find the information. We gather back together and add to the graphic organizer. To "assess/grade" I have them write two ways that bats are alike and two ways bats are different.