Immigrants lost in the blistering expanse of the Sonoran Desert, problem bears, bats pollinating saguaros, a Good Samaritan filling tanks at emergency water stations, and the terrified runaway boy who shoots him pierce the heart and mind of Rosana Derais. "Vanishings," the first story in Silence & Song, is a love letter, a prayer to these strangers whose lives penetrate and transform Rosana's own sorrow.   In "Translations," the prose poem connecting the two longer fictions, child refugees at a multilingual literacy center in Salt Lake City discover the merciful "translation" of dance and pantomime.   The convergence of two disparate events--a random murder in Seattle and the nuclear accident at Chernobyl--catalyze the startling, eruptive form of the concluding piece,"requiem: home: and the rain, after." Narrated in first person by the killer's sister and plural first person by the "liquidators" who come to the Evacuation Zone to bury entire villages poisoned by radioactive fallout, "requiem" navigates the immediate trauma of murder and environmental disaster; personal and global devastation; and the remarkable recovery of the miraculously diverse more-than-human world.