152 BULLETIN 203, UNITED STATES NATIONAL MUSEUM 



"The only laboratory report available on the food of the species per- 

 tains specifically to a South American subspecies of the pitiayumi 

 j^roup. The stomach contents were reported to consist of remains of 

 hymenopterous insects and two-winged flies (Zotta, 1932)." 



Nothing further seems to have appeared in print regarding the 

 habits of this warbler. It is much like the well-known parula warb- 

 ler in appearance and behavior, but can be recognized in the field by 

 the conspicuous black lores and cheeks and by the complete absence 

 of any pectoral band. 



DISTEIBUTION 



Range. — The species ranges from southern Texas to northern Argen- 

 tina and Uruguay. The race occurring in the United States is found 

 in southern Texas and northeastern Mexico. 



Breeding range. — Sennett's olive-backed warbler breeds north to 

 northeastern Coahuila (Sabinas) ; and southern Texas (Hidalgo, 

 Harlingen, and Point Isabel) . East to southern Texas (Point Isabel 

 and Brownsville) ; and southeastern Tamaulipas (Altamira and 

 Tampico). South to southern Tamaulipas (Tampico) ; and southern 

 San Luis Potosi ( Valles) . West to eastern San Luis Potosi ( Valles) ; 

 and eastern Coahuila (Cerro de la Silla and Sabinas). 



Winter range. — While probably not a sedentary form, its winter 

 range very nearly coincides with its breeding range. It has been 

 found in winter from Brownsville, Tex., to northern Hidalgo 

 (Jacala). 



Egg dates. — Texas : 6 records, April 28 to May 30 ; 4 records, May 2 

 to 12, indicating the height of the season. 



Mexico : 2 records. May 27 and July 5. 



PARULA GRAYSONI Ridgway 

 SOCORRO WARBLER 



HABITS 



The Socorro warbler is closely related to Sennett's warbler and 

 other races of pitiayumi but is accepted as a distinct species. It dif- 

 fers from nigrilora in having gray, instead of black, lores and cheeks, 

 and in having much less white on the inner webs of the outer rectrices. 

 It was supposed to be confined to Socorro Island, one of the Kevil- 

 lagigedo group, about 250 miles southwest of the southern tip of 

 Baja California. It was added to our fauna by Chester C. Lamb 

 (1925), who states: 



On November 3, 1923, I collected one of these birds at Todos Santos, ou the 

 PaciSc Ocean side of the peninsula of Lower California, some forty miles nortli 



