152 U.S. NATIONAL MUSEUM BULLETIN 233 



had found parasitized nests of tliis species. In the collections of the 

 Hancock Foundation at the University of Southern California there 

 is an egg of the brown-headed cowbird, from a nest of a brown towhee 

 collected at Alhambra, California, on June 13, 1944. The host in 

 that area is the race PJ. senicula. The Arizona and California records 

 involve the southwestern race of the parasite, M.a. obscurus; the 

 New Mexico ones refer to the nominate race, M.a. ater. 



Abert's Towhee 



Pipilo aberti Baird 



Abert's towhee is a rather poorly known and little studied species* 

 but it has been found to be parasitized by the small race of the brown- 

 headed cowbird, M.a. obscurus, at least nine times in southern Arizona 

 and at least once in California (Westmoreland, Imperial County). 

 The latter set is now in the San Bernardino County Museum. Brown 

 (1903, p. 47) merely reported it as a molotlu^ine victim in Ai'izona 

 without giving any actual instances. G. F. Breninger, however, 

 collected a parasitized set of eggs at Phoenix, on May 2, 1896, a set 

 now in the collections of the California Academy of Sciences. As 

 recorded in my first account (1929, p. 228), A. B. Howell found a 

 parasitized nest about four miles southwest of Gadsden, on May 20, 

 1918. The late J. Hooper Bowles wrote me that he had in his col- 

 lections two more records, one collected at Mesa on May 14, 1919, 

 and one from the same place on June 19, 1921. One nest contained 

 2 eggs of the host and 2 of the parasite and the other held 3 eggs of 

 each. 



J. T. Marshall, Jr. (in litt.) informed me that, in the mesquite woods 

 of the San Xavier Keservation, ten miles south of Tucson, Aiizona, 

 he noted four parasitized nests of Abert's towhee. He wrote me 

 that this bird usually started to nest before the cowbirds arrived in 

 the spring and that the early broods have a chance of coming to suc- 

 cessful fruition without interference by the parasite. Another record 

 from Tucson is a parasitized set of eggs, taken in 1917 and now in 

 the Santa Barbara Museum of Natural History. 



The various records given above involve both races of the host, 

 aberti and dumeticolus. 



Rusty-crowned Ground Sparrow 



Melozone kieneri (Bonaparte) 



J. Stuart Rowley (mss.) found that this sparrow frequently was 

 parasitized by the bronzed cowbird in Morelos, Mexico; but in one 

 nest he also found an egg of the brown-headed cowbird, M.a. abscurus. 

 The local race of the host is M.k. ruhricatum. 



