The Winter Society of the Oregon Junco: The Flock

Abstract

mountains, has an elevation of 5000 feet and is about fourteen miles long by four miles wide. It has no settlement except the Deep Springs School, which operates a cattle ranch and has about 150 acres under cultivation. Lines of large cottonwoods follow the irrigation ditches. Lawns, deciduous trees, and shrubs partly surround the buildings. About 25 feet away from the feeding station a belt of fifteen deciduous trees separated it from the low desert vegetation of the basin as a whole and furnished perching places. In Seattle the feeding station was in a residential area but was about 300 feet from a heavily wooded section to the north and about 200 feet from a narrow strip of woods to the east. Connecting this wooded strip with the feeding station area was a vacant lot covered with weedy hummocks and heaps of stones and brush. This lot had nine large conifers. There was also a line of trees, largely conifers, running along the back lot lines of the houses in the block. Canary grass seed and chick feed were the foods provided. The feeding stations were strips of ground twelve feet by four, running parallel with and about six feet from the wall of the house, centered on a window, and bordered on the ends and outer side by heaps of brush from three to seven feet high, in which the birds perched, rested, and took cover. Being indoors the observer was able to make prolonged day-to-day observations regardless of weather. At Deep Springs, 435 hours were spent at the post of observation between October 24, 1948, and January 25, 1949. Observations were resumed on February 20 and totalled about 50 hours before the departure of the birds in March. In Seattle 365 hours were spent in observation between December 28, 1949, and April 3, 1950. The birds were marked by cementing (with Duco) one or two trout-fly feathers to the top pair of tail feathers close to the body. These markers were durable and varied naturally in shape, texture, and the curve of the shaft, as well as in color. They were trimmed if necessary to about the length of the tail and were cemented to it wrong side up, to be made more readily recognizable by the upward curve of the shaft away from the tail. The markers were conspicuous but did not seem to be noticed either by the wearer or its fellows. When eating in a high wind the marked birds had a little more difficulty with their footing than the unmarked ones, but not to a serious extent. The birds were easily distinguishable as individuals. Marked individuals were named with letter symbols by assigning a different letter to each type of feather; B stood for blue, N for black, and so on. This system brought the name of the bird instantly to mind, a crucial point in observations which rely on the correct identification of swift-moving little birds. Furthermore, the relative positions of the feeding station and the observer were such as to bring the birds within a range of about six to fifteen feet. For observations outside the station binoculars were used as needed. The observer at a feeding station cannot choose his material. Not knowing which species would prove useful, the writer marked every bird trapped, with the resultant discovery that the juncos formed the only stable visiting group. At Deep Springs 239