270 U. S. NATIONAL MUSEUM BULLETIN 211 



boro, September 23. Florida — Miami, November 8; Pensacola, 

 November 2. Bermuda — October 12. 



Egg dates. — Illinois: 14 records, May 25 to June 14; 7 records, 

 May 29 to June 10. 



Massachusetts: 31 records, May 23 to June 9; 17 records, May 30 

 to June 5. 



New York: 19 records, May 25 to June 10; 10 records, May 31 to 

 June 4. 



ICTERUS BULLOCKII BULLOCKII (Swainson) 



Bullock's Oriole 

 Plate 20 

 HABITS 



This highly colored oriole replaces the Baltimore oriole in the western 

 half of North America, except for a narrow strip along the Pacific 

 coast from the San Francisco Bay region to northern Baja California. 

 Its breeding range extends from the southern parts of British Colum- 

 bia, Alberta, and Saskatchewan to southern Texas and northern 

 Mexico, and from the western edge of the Great Plains and prairie 

 regions to the Pacific slope. At the eastern border of its range, where 

 it meets that of the Baltimore oriole, these two closely related species 

 appear to interbreed, producing an interesting series of apparent 

 hybrids, to be referred to later. 



The favorite haunts of Bullock's oriole are in the growths of deciduous 

 trees, cottonwoods, willows, sycamores, etc., that line the streams or 

 irrigation ditches in open country, in the prairie regions, and in 

 cultivated lands. The presence of water is not essential, for they are 

 equally at home in some of the partially dry washes that extend down 

 into the grasslands from the mountain canyons, where there is some 

 underground moisture, or far from any water in the tree-claims 

 about the ranches; they are also found living and nesting in the 

 semiarid mesquite groves in Arizona. It is, perhaps, less intimately 

 associated with human habitations than is the more sociable Baltimore 

 oriole, though it does nest to some extent in villages and near houses, 

 especially about farms and ranches. 



Nesting. — Bendire (1895) describes this very well as follows: 



The nest resembles that of the Baltimore Oriole, but as a rule it is not quite 

 as pensile, and many are more or less securely fastened by the sides as well as by 

 the rim to some of the adjoining twigs. The general make-up is similar. As 

 many sections where Bullock's Oriole breeds are still rather sparsely settled, less 

 twine and such other material as may be picked up about human habitations 

 enter into its composition. Shreds of wild flax and other fiber-bearing plants 

 and the inner bark of the juniper and willow are more extensively utilized; these 



