128 University of California Publications in Zoology [Vol. 12 



the California side, where the river swings northwest against the 

 mesa, a nesting site was located as we floated past on May 5. The 

 place was revisited on May 10, and the hole in the partly cemented 

 gravel face, fifteen feet above the water, was ascertained to contain 

 four downy young. Two of these were preserved (nos. 12695, 13979). 



Otus asio gilmani Swarth 

 Saguaro Screech Owl 



The widespread presence of screech owls was brought to our atten- 

 tion by their notes heard almost nightly and at nearly every one of 

 our camps from Needles all the way down the river, clear to Pilot 

 Knob. The birds appeared to occur both in the willow and cotton- 

 wood timber close along the river, and out on the desert. They were 

 heard from the precipitous sides of The Needles, the numerous cran- 

 nies in the rock walls of which may have afforded the birds daytime 

 concealment. At Mellen, Arizona, February 27, a female screech owl 

 (no. 12696) was captured in a trap set near the house of a wood-rat 

 (Neotoma albigula venusta) under a mesquite and baited with portions 

 of a wood-rat found partly eaten in the same trap the night before. 



On the California side, twenty miles north of Picacho, April 16, 

 one (no. 12697) was shot at night in a willow when giving the char- 

 acteristic deep-toned succession of mellow notes; it proved to be a 

 male. 



April 23, on the California side four miles above Potholes, two 

 were taken from holes in giant cactuses. A male (no. 12698) was 

 taken from an otherwise empty cavity ten feet above the ground. A 

 female (no. 12699) occupied a cavity nine feet above the ground. 

 This hole was rather small, evidently originally excavated by the Gila 

 woodpecker; but it held besides the old owl, three newly-hatched 

 young (preserved as alcoholics, nos. 13976-13978), and the fresh, 

 headless bodies of four mammals: two Perognathus penicillatus penicil- 

 latus, one Dipodomys merriami merriami, and one Pcromyscus mani- 

 culatus sonoriensis. 



The four adults specified above, together with a fifth in the Museum 

 (no. 4395) taken by J. G. Cooper at Fort Mohave, February 24, 1861, 

 are all typical of the subspecies gilmani as described by Swarth (1910, 

 P. 1). 



