The house sparrow, nobody's favorite bird, is a ubiquitous urban resident whose catholic tastes and true feathers--morphologically, it's a weaver finch--are revealed in the last, longest, and most ambitious piece in this agreeable collection. In the others, New Yorker writer Kinkead discourses pleasantly on local geology and Central Park wildflowers (somewhat stunted by automobile fumes), and recalls birders' delight when a Steller's eider, common to Siberian waters, floated inexplicably along the Massachusetts coast. Another suspensefully chronicles the search for an elusive tree species--Betula uber, or Ashe's birch--which determined researchers tracked down from early 20th-century references 60 years before. And a diverting piece on coyotes, highly intelligent animals, finds them howling contentedly in Westchester and L.A. suburbs, the unlikely beneficiaries of wolf-extermination policies. Kinkead writes in a clear, unencumbered style, imparting information and natural appreciations with a keen eye for the hardier varieties of urban wildlife.