Several subspecies of this woodpecker are found only in Central and South America, but three varieties occur regularly in the United States, while two others are confined to Baja California. The true ant-eating woodpecker (_B. f. formicivora_), which ranges through eastern and southern Mexico, is found also in south-central Texas (Chisos Mountains and Kerrville). Mearns’s woodpecker (_B. f. aculeata_) occupies the range in Arizona, New Mexico, and western Texas (Fort Davis) south through the Mexican States of Sonora, Chihuahua, and Durango. The California woodpecker (_B. f. bairdi_) is found in the Pacific coast region from Oregon south to northern Baja California. In this Mexican State the narrow-fronted woodpecker (_B. f. angustifrons_) is confined to the region of Cape San Lucas, while the San Pedro woodpecker (_B. f. martirensis_) is found in the northwestern part of the area nearly to the United States border. _Egg dates._--Arizona: 9 records, May 10 to June 10. California: 66 records, April 2 to June 15; 33 records, April 20 to May 15, indicating the height of the season. Second and third broods have been found in September and October. Baja California: 4 records, May 10 to June 3. BALANOSPHYRA FORMICIVORA BAIRDI (Ridgway) CALIFORNIA WOODPECKER PLATE 28 HABITS The above common name is well chosen, as this is one of the commonest and most conspicuous birds throughout its range in California. Anyone who spends much time afield in the valleys, foothills, and canyons of southern and western California is sure to see this strikingly colored and active woodpecker making itself conspicuous among the oaks and pines; and, where one is seen, there are almost sure to be others, for it is a sociable species. Referring to the Lassen Peak region, Grinnell, Dixon, and Linsdale (1930) say: Two environmental factors of seeming importance for the presence of this bird were an available supply of acorns and wood or bark of sorts into which the birds could bore storage holes. As to species of oak, out of the six or more present, our impression remains that no outstanding choice by the woodpeckers was shown. About as many of the birds were seen among the black oaks in the vicinity of Payne Creek P. O., as among the valley oaks around Cone’s. However, tracks of black oaks recurred east of the main mountain mass in the section, as along the upper Susan River and near Eagle Lake, where no California woodpeckers were ever seen by us. To repeat, none of this species of woodpecker was seen by us east of about the western edge of the yellow pine belt (Transition life-zone). * * *