Dr. Heermann, in a subsequent visit to the State, mentions it as being a very common bird in all parts of California. They were once quite numerous among the hollow trees in the vicinity of Sacramento, but have gradually disappeared, as their old haunts were one by one destroyed to make way for the gradual development and growth of that city. Dr. Heermann found a large number in the winter, sheltered during the day among the reeds of Suisun Valley. They were still abundant in the old Catholic Missions, where they frequented the ruined walls and towers, and constructed their nests in the crevices and nooks of those once stately buildings, now falling to decay. These ruins were also a shelter for innumerable bats, reptiles, and vermin, which formed an additional attraction to the Owls. Dr. Cooper speaks of finding this Owl abundant throughout Southern California, especially near the coast, and Dr. Newberry frequently met with it about San Francisco, San Diego, and Monterey, where it was more common than any other species. He met with it on San Pablo Bay, inhabiting holes in the perpendicular cliffs bordering the south shore. It was also found in the Klamath Basin, but not in great numbers. Mr. J. H. Clark found the Barn Owl nesting, in May, in holes burrowed into the bluff banks of the Rio Frio, in Texas. These burrows were nearly horizontal, with a considerable excavation near the back end, where the eggs were deposited. These were three or four in number, and of a dirty white. The parent bird allowed the eggs to be handled without manifesting any concern. There was no lining or nest whatever. Lieutenant Couch found them common on the Lower Rio Grande, but rare near Monterey, Mexico. They were frequently met with living in the sides of large deep wells. Dr. Coues speaks of it as a common resident species in Arizona. It was one of the most abundant Owls of the Territory, and was not unfrequently to be observed at midday. On one occasion he found it preying upon Blackbirds, in the middle of a small open reed swamp. It is not uncommon in the vicinity of Washington, and after the partial destruction of the Smithsonian Building by fire, for one or two years a pair nested in the top of the tower. It is quite probable that the comparative rarity of the species in the Eastern States is owing to their thoughtless destruction, the result of a short-sighted and mistaken prejudice that drives away one of our most useful birds, and one which rarely does any mischief among domesticated birds, but is, on the contrary, most destructive to rats, mice, and other mischievous and injurious vermin.