We are blessed with an abundance of mature trees on the Greater West Side of Chicago. And that means birds are flying above us all the time.  What makes them want to stop and linger in a particular garden? Jim Gill and Elaine Petkovsek are making that discovery. For the past year, they have been working on creating a “bird garden” in their backyard. They are putting the finishing touches on a project that’s taken some muscle, a little research… and becoming a bit of a bird-brain.