Looking back, all was lost the moment I resolved to do something about the tree squirrels, more than a year ago. All I wanted, truly, was to feed the backyard birds. We’d been in the house a short time, not long after we left the city; I bought an old-school spherical feeder, the sort I remember hanging outside my grandparents’ window in North Woodmere, attracting cardinals, bluejays, robins, and the like.