The Ashy Storm-Petrel, a tiny, dark-gray seabird, nests on 11 rocky, isolated islands in the Pacific Ocean off the coasts of California and Mexico. Weighing little more than a hefty greeting card and forced to contend with invasive rats, mice and cats, aggressive seagulls, oil spills and sea-level rise, it faces an outsize fight for survival. At last count, only 10,000 remained. Several other species of storm-petrels are similarly endangered.