I should like to hear of observations from the Cajon Pass and points in the vicinity of Antelope Valley.
With this interest in the thrasher during migration it was with much pleasure I looked forward to studying him during the season of family cares; and when spring opened in southwestern Colorado I began sharpening eyes and pencil. But no thrashers appeared and I had about given up hope of seeing him in his summer home when a wagon trip thru part of Montezuma County down into the Southern Ute Indian Reservation gave me opportunity for a few observations. My time was limited and only superficial work could be done. I saw the first birds in the sage brush near Cortez, the county seat of Montezuma County, altitude near 6000 feet. They were rather tame, flying from brush along the roadside up onto fence posts. Two or three old nests were seen but the birds were not numerous.
From Cortez southward was a constant tho gradual descent toward the San Juan River. As the altitude decreased the number of thrashers increased and more old nests were seen. I had no time, while en route, for search, but during the noon hour I "took to the brush" and found the first new nest. It was in a thick sage bush (Artemisia tridentata) and was discovered by flushing the birds from an adjoining bush. The nest contained the shells of two freshly broken eggs, the cause of breakage not being apparent and the nest not otherwise disturbed. This was on May 31. Later in the day I saw two families of young birds that had just left the nest, one brood of nestlings not being able to fly sufficiently to escape capture and inspection. The discovery of these birds so nearly matured left me small hope of finding any eggs.
That afternoon I reached Navajo Springs, the Southern Ute Agency. The agency is near the New Mexico line and is located in a narrow pass between Ute Peak and a line of bluffs capped with the characteristic rim-rock of this country. A cut or arroyo begins a mile above the agency and extends down the pass, deepening all the while. A small stream of water was flowing along the bottom for possibly two miles before sinking. On each side of the cut was a strip of bushy or shrubby growth composed of sage brush, grease-wood (Sarcobatus vermiculatus), and another desert shrub not familiar to me. Locally it is called "chico-brush" and is a good indication of alkali in the soil.
In this growth were many thrashers, some few lark buntings and several mocking-birds. Taking advantage of what little daylight remained, after putting up my team I made a hasty search in the immediate vicinity of the agency and found two nests with eggs. The first was in a sage two and one-half feet from the ground and contained seven beautiful greenish-blue eggs specked with rich brown. This nest was made of dry twigs from sage and grease-wood, and was lined with sage bark, horse hair, goat hair, and rabbit fur. The second nest was also in a sage bush and about two feet from the ground. It was similar in construction to the first but the lining contained no rabbit fur and the set was of six eggs. Both sets were about one-third incubated.
June 1, I was again afield for a short time and found two more nests. One was in a grease-wood two and one-half feet from the ground and contained six eggs about as much incubated as those found the day before. This nest was similar to the others except for a distinct arch or platform of dry twigs just above it. The arch looked more like design than accident but I formed no decided opinion in regard to it. The fourth nest was in a sage two feet from the ground and contained three fresh eggs. In addition to these thrashers' nests I found a lark buntings' nest with five fresh eggs, and a mocking-birds' with five partly incubated eggs; also some young chipping sparrows.
