The Cowbirds 



ency to cloud capping. Av. size (of ater ater): 21.5 x 16.4 (.84 x .65). Season: In- 

 determinable, April to July. 



Range of Molothrus ater. — North America from about Latitude 6o° in west 

 central Canada south over the Mexican plateau. 



Range of M. a. artemisicc. — Presumably the Great Basin region north into 

 British Columbia. Breeds chiefly in the Upper Sonoran zone and winters south into 

 Mexico. 



Distribution in California. — Summer resident, not common, in the plateau 

 region east of the Sierras, south perhaps to Death Valley (A. K. Fisher [Grinnell]) 

 and Yermo on the Mohave desert (Lamb), although region of intergradation with 

 obscurus undefined. Casual (?) west of the Sierras (Farallon Ids., June 2, 191 1). 



Authorities. — Gambel (Molothrus pecoris), Proc. Acad. Nat. Sci. Phila., vol. iii., 

 1847, p. 204; Grinnell, Univ. Calif. Publ. Zool., vol. 5, 1909, pp. 276-281, 2 figs, (descrip- 

 tion of artemisiae; critical); Dawson, Condor, vol. xiii., 1911, p. 186 (occurrence on 

 Farallons); Obcrholser, Auk, vol. xxxiv., 191 7, pp. 327-328 (critical; range). 



No. 12b Dwarf Cowbird 



A. O. U. No. 495a. Molothrus ater obscurus (Gmelin). 



Description. — Similar to M. a. artemisim, but much smaller; the female slightly 

 paler. Av. erf 11 males (after Grinnell): wing 100. 1 (3.94); tail 68.4 (2.69); bill 16.5 

 (.65); depth at base 9.2 (.36); tarsus 24.1 (.95) 



Nesting. — As in preceding form. Eggs: decidedly smaller, Av. of 40 eggs from 

 Arizona in the M. C. O. coll. 20 x 14.5 (.76 x .57). Extremes: 17.5-20.8 by 13. 5-15. 5 

 (.69-. 82 by -53--6i). 



Range of At. a. obscurus. — The southwestern United States from southern Texas 

 west to southern California, and south in Mexico to Colima and Jalisco. 



Distribution in California. — Summer resident in southern California and in 

 the Tulare basin; commonly along the Colorado River and on the Colorado desert, 

 north to Independence (Grinnell), Bakersfield (Grinnell), Buena Vista Lake (Mailliard), 

 Weldon (Grinnell), and Fresno (Tyler, although possibly not breeding), and more 

 sparingly in the San Diego district, west at least to Santa Barbara (Dawson, several 

 occurrences). Winters in the Colorado River valley and on the Colorado desert, west 

 at least to Mecca (January 30 and February 4, 1913; also van Rossem). 



Authorities. — Cooper (Molothrus pecoris), Orn. Calif., 1870, pp. 257-260 (egg 

 in Chat nest in Colorado Valley) ; Bendire, Rept. U. S. National Mus. for 1893 (1895), 

 PP- 597-599 (general account) ; Grinnell, Univ. Calif. Publ. Zool., vol. 5, 1909, pp. 278- 

 281; ibid., vol. 12, 1914, pp. 157-160 (critical; range); Law, Condor, vol. xii., 1910, p. 174 

 (in Los Angeles Co.; habits); Tyler, Pac. Coast Avifauna, no. 9, 1913, pp. 67-68 (in 

 Fresno district); Dawson, Condor, vol. xviii., 1916, p. 27 (at Santa Barbara); Ober- 

 holser, Auk, vol. xxxiv., I9l7,pp. 327, 328 (crit.; range); Hanna, Condor, vol. xx., 1918, 

 pp. 211-212 (nests parasitized). 



IT MAY be urged with some show of justice that every bird-person 

 deserves a sympathetic biographer. Even criminals on trial for their 

 lives are entitled to legal defense. Well, then, let who will be defender. 

 I will be prosecuting attorney. " J' accuse." The prisoner at the bar 



7 6 



