When cattle left the San Marcos Foothill Preserve, the ground-nesting birds soon flew away. The native bunch grasses that had provided space for their nests had become crowded out by nonnatives. To bring back the native grasslands, Channel Islands Restoration has hired a herd of sheep in a two-year habitat restoration project. The herd will rotate daily through a series of pastures for about a month to encourage native plants, and birds, to return and thrive.