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Nov,,1914 EFFECTS OF IRRIGATION ON BIRD LIFE IN WASHINGTON 255 increased in numbers, and with the Brewer Blackbirds search every newly cut alfalfa field for insects, and probably keep the caterpillar in check. The valley fauna is noticeably lacking in the small arboreal insectivorous birds, such as vireos, warblers and chickadees, partly, perhaps, because of the scarcity of arboreal vegetation. All fruit trees have to be conscientiously sprayed. The changed conditions have not only affected the resident species but have also attracted various winter visitants, the most abundant of which are the Gambel Sparrow (Zonotrichia 1. #arabeli) and, as I noted before, the Short- eared Owl. Various migrants spend several weeks in spring and fall, the most abundant species of which are the Audubon Warbler (Dendroica auduboni) and the Pipit (Antbus rubescerts). Palo Atto, Calgf o?nia, August BREEDING OF THE BRONZED COWBIRD IN ARIZONA By M. FRENCH GILMAN WITH TWO PHOTOS BY H. T. MURPHY N THE CONDOE for September-October, 1909, I recorded the capture at Saca- ton, Arizona, of what at the time I believed to be the Red-eyed Cowbird. In the July issue of The Auk of that year Mr. S.S. Visher recorded a male taken at Tucson; but in a later number of the same journal he published a cor- rection, stating that it was the Bronzed Cowbird (Tangavius aeneus aeneus), the form from northwestern Mexico, instead of the Red-eyed Cowbird (Tanga- vi?s aeneus involucratus), of Texas and eastern and southern Mexico, as was previously supposed. Soon after my note appeared in THE CONDOS Mr. Wells W. Cooke, of the United States Biological Survey, wrote me to send him a specimen of the female, and he pronounced the bird submitted, sent June 11, 1910, to be Tangavius a. ae?ieus. The first year that these Cowbirds appeared at Sacaton I saw at least two pairs, and possibly more, and they were mating, so presumably breeding. The year 1910, the first one of the season was seen May 9. On July 12 I found a young one on the .ground under a cottonwood tree, just below an inaccessible Bullock Oriole's nest. All that spring from the time the first bird appeared, I had been carefully examining nests of Abert Towhees and Red-wing Black- birds, thinking perhaps the cowbirds might deposit their eggs therein, as the're is some similarity in size and ground color of the eggs of these several species. I examined about fifty of the towhees' nests and about half as many of the red-wings', but without success. The number of cowbirds seen during 1910 was about the same as the year previous. The year 1911 I was working on the north side of the Gila River about four miles from Sacaton, and did nothing with them that season, though occa- sionally seeing two or three on the lawns at Sacaton. The next season, 1912, I was located on the north side of the river at an Indian village called Santan, and was in a position to take up the study again. I saw the first Bronzed Cowbird of that season at Sacaton on May 25, and June 5, a male appeared