In Boston, we share space with three warm-blooded creatures: squirrels, pigeons, and rats. Squirrels are generally well-loved and rats are hated. Pigeons occupy a more ambiguous territory but are ubiquitous in successful urban spaces – think Trafalgar Square and the Piazza San Marco. But how far outside of the city do pigeons live? In Fairfield County, Connecticut, big black crows are the dominant nuisance bird both because of their size and color, but mostly because of their distinctive “caw caw” call. Is there a hidden pigeon-crow boundary that tracks through Milton, Roslindale, West Roxbury, and the parking lots behind the stores in Coolidge Corner? Do pigeons and crows do battle along this line? Is there a negotiated DMZ to reduce casualties?