A good, tough critical roundup of some radical methods which are being used to rescue threatened species of birds. Zimmerman is impatient with the prevalent romantic ""mourning"" for dwindling populations; ""it is far more difficult to fight extinction, a law at a time, an acre at a time, a species at a time, an animal at a time."" Among the dramatic ventures: an egg-transfer method to preserve the DDT-blighted ospreys of Connecticut; safe-guarding Bermuda's cahows by the invention of an apparatus for excluding larger predators from the cahows' nesting sites; and the rescue of the whooping crane (Zimmerman has a good deal to say about what some have termed ""mishandling and mismanagement"" of the whooper ""farm"" in Patuxent, Md.). There are vivid descriptions of visits to a training-for-release session with a peregrine falcon in New York State; a vulture ""restaurant"" in Spain; and a European attempt to offset the Cain/Abel tendecy of sibling eaglets to kill each other off. The most arresting and oddly moving chapter has to cio with the beautiful little Kirtland warbler, and the five-decade quest to preserve it to which a twenty-year-old Leopold (of Leopold and Loeb) contributed. And there's the remarkable story of how a duck species may have rebounded from one surviving female bird. Zimmerman is quite obviously on the side of the intelligent activist: ""Natural scientists are wont to study a problem to death. Clinical scientists must act immediately in a crisis."" A lively report for laymen and ornithologists, some whom may take umbrage at Zimmerman's plucking of some sacred tail feathers.