Great Destruction of Birds' Eggs and Nestlings in the Sierra Nevada

Abstract

AS WE approached Cisco, Placer County, California, toward evening of June 7, 1912, the air seemed filled with the songs and call-notes of mountain birds. Observing that we had reached a section where birds were more numerous than is usual at so high an altitude as 5900 feet, I stopped my automobile at the only hotel in that charming resort and engaged accommodation for Mrs. Ingersoll and self. Knowing of no locality in the Sierras where small birds nested more plentifully than in that particular place, I anticipated the pleasure of adding much choice material to my collection of eggs. A few days' search, however, convinced me that I was not the only nest hunter, and that the Bluefronted Jays had a great advantage over one who collects full sets only. Jays were no more abundant than in similar places elsewhere, but these particular birds doubtless had an extra strong desire for eggs and naked birds. No jays were detected in the act of eating well-feathered young. Other natural enemies were doubtless the cause of some of the nests being tenantless. But as the jays were the only robbers caught in the act of taking eggs and young, the principal havoc is attributed to them and to an unseasonable snow fall. It is to be hoped that birds in the surrounding localities were more fortunate in raising their young. For a wide spread destruction like that at Cisco would tend to wipe some species out of existence. Following a week of delightful weather, a cold rain began falling on the morning of June 22, by night turning to sleet. At six o'clock on the morning of June 23 there was a depth of three and one-half inches of snow on the level. This snow was of a wet, clinging nature, weighing down every leaf and twig, and causing large branches and limbs of some deciduous trees to break. Clumps of bushes were generally weighted down to about half their height on the previous day. Many nests that were on flexible branches had their contents spilled out, while those built against trunks of small trees or between the main stems of bushes were later in the day bombarded with huge chunks of snow dislodged by the wind. This permitted branches to spring violently up to their accustomed position, a further cause of destruction. Horizontal branches of large fir trees drooped and crushed nests that chanced to be located between them. It is easy to imagine that many sleeping birds were crushed to death as the snow-laden branches quietly settled on them. Personally I know of two instances. A brooding Audubon Warbler was killed, and two of her three eggs broken, in the nest situated thirty feet above the ground on the branch of a fir. The other instance was that of a Western Wood Pewee picked up from the ground with nest on dead aspen limb that had broken off and fallen from a height of some twenty feet. Another Wood Pewee's nest destroyed in the same manner, was found later in the day. While searching a large pine stub for the nest of a Sierra Creeper, I discovered a female Calaveras Warbler under a partially detached piece of bark. Her feathers were quite wet, and as the crevice was rather dry, I presume this ground-nesting bird was flooded out of her home and sought shelter as death approached.