THE PRAIRIE KEEPERS by Marcy Houle...

THE PRAIRIE KEEPERS by Marcy Houle (Addison-Wesley: $11; 266 pp.). Houle recounts the summer she spent studying three species of hawks in a largely undisturbed grassland in northeastern Oregon. She discovered a link between the unexpectedly dense hawk populations and the wise stewardship of local ranchers, who managed their grazing allotments carefully (“a shining example for other rangelands across the country”). The lush foliage that resulted nourished not only cattle, but hordes of ground squirrels, which fed the hawks. Houle interweaves science with lively accounts of her struggles to survey the huge range, win over hostile ranchers and fend off would-be suitors.