April is not the cruelest month in the scablands of southeastern Washington. In a week, pink phlox would carpet the undulating desert landscape below Rattlesnake Mountain, followed soon after by a rush of violet lupine. On a clear day with only a slight breeze, U.S. Fish and Wildlife Service biologist Heidi Newsome walked up a canyon, seeking signs of the rare buteo regalis, or ferruginous hawk, so named for the rusty hue of its feathers. No one else was around; this ecology reserve is closed to the public. Far out on the northern horizon, next to a sharp turn in the Columbia River, Newsome could see a few trucks, cranes and old concrete buildings. But as she made her way up Bobcat Canyon, all she could hear were the red-tailed hawks, northern harrier, chukar partridge and migrating bluebirds. No ferruginous hawks, though. Newsome was, and is, a little worried