254 BULLETIN 197, UNITED STATES NATIONAL MUSEUM 



other Vireos of the smaller class, is usually found in the bottom lands 

 along the shores of the Upper Missouri river, from the neighbour- 

 hood of the Black Snake Hills as far as we went up that river ; finding 

 it in many instances, whether in the bottom lands, overgrown with low 

 shrubbery, or along the borders of ravines that discharge the water 

 accumulating during the spring meltings of the snows that cover the 

 upper country prairie land." 



The species, Vireo belli, is widely distributed over the western 

 United States and northern Mexico, but the type race is found only 

 east of the Rocky Mountains, from southern South Dakota, northern 

 Illinois, and northeastern Indiana to eastern Texas and Tamaulipas. 



Like the white-eyed vireo. Bell's is a denizen of low dense thickets, 

 preferably along the banks of a river or some small stream. Wliere 

 the ranges of the two species overlap, they are often found in similar 

 haunts or in the same thickets. Bell's vireo seems to show a preference 

 for thickets of wild plum or small, densely leaved plum trees. But 

 it is also often found in thickets of hazel bushes, alders, haws, willows, 

 or dogwoods, specially those that are overgrown with a tangle of 

 wild grapevines. 



In Texas, according to George F. Simmons (1925), its habitats are: 

 "Mesquite flats and mesquite prairie forests ; tangled brush and brier 

 patches in open country; mesquite thickets bordering open prairie or 

 cotton fields ; lines of bushes and trees along country roads and fence 

 rows between cultivated fields; brush fringing woods or roadsides; 

 osage-orange or bois-d'arc hedges ; orchards ; plum thickets on prairie 

 or on country hillside." 



Spring. — Of the spring migration in Central America, Dickey and 

 van Rossem (1938) write: "From April 5 to 9, 1927 a marked wave 

 of this species was migrating through the beach scrub and more 

 open parts of the woodland at Barra de Santiago. As the males 

 were then in full song, they were naturally more conspicuous than 

 would otherwise have been the case. Even so, it was obvious that 

 large numbers were passing through, and in the low growth along the 

 peninsula as many as a dozen birds were in sight or sound at one time. 

 The evidence of a fall and spring migration in El Salvador, without 

 the detection of a single winter visitant, argues that some individuals, 

 at least, winter considerably to the southward." 



Nesting. — Harold M. Holland, of Galesburg, 111., writes to me: 

 "During the i:>ast 40 years or so, upward of a hundred nests of Bell's 

 vireo have been examined by me in this west-central Illinois locality. 

 None of these has contained more than four vireo eggs, which is the 

 normal complement. Fresh eggs have been noted from May 25 to 

 June 15. The characteristic and unmistakable song, when heard 

 in proper season where surroundings offer a favorable site, is indica- 

 tion usually of a nest near at hand. 



