232 NESTS AND EGGS OF 



deep. Nests saddled on thick limbs are usually larger. In Ohio the 

 Ruby- throat prefers nesting in the branches of the buckeye to all other 

 trees. The birds are especially abundant about this tree when it is in 

 full blossom early in May. The nesting time is from about the 

 middle of May to the latter part of June. The average size of thirty 

 eggs is .51X.34. 



429. TrocMlus alexandri Bourc. & Muls. [336.] 



Black-chmned Humm.ing'blrd. 



Hab. Western United Stntes, from the Rocky Mountains to the Pacific, south into Mexico. 



This Hummingbird nests in more open ground than the Rufous 

 or Anna's, placing the structure usually on the small branches of oaks 

 and sycamores. Sometimes it rests lightly in the forks of a slender 

 twig. It is composed of the web or down found on the under side of 

 the leaves of the sycamore ; the effect is that the nest looks like a small, 

 round, yellow sponge. Eggs same as those of the Ruby-throat, with 

 an average size of .50 x .30. 



Mr. W. E. D. Scott states that this species is an abundant summer 

 resident in the Catalina mountains in Southern Arizona, and by the last 

 of May the birds are mated and begin breeding. He found fresh eggs 

 as late as July and early in August. Mr. Stephens notes this Hum- 

 mingbird as not common in the San Benardino Valley. A nest taken 

 May 22 was built in a willow, eight feet from the ground, and contained 

 two eggs in which incubation had commenced. 



430. TrocMlus costse (Bourc.) [337.] 



Costa's Hmumingbird. 



Hab. Lower California, Western Mexico, Arizona and Southern California. 



Costa's Hummingbird is more or less abundant in various 

 regions of Arizona and Southern California. It is not generally so 

 abundant as the Black-chinned Hummingbird, in whose company it is 

 often found breeding. Small streams in the mountain canons, fringed 

 with alder, laurel, sycamore and other shrubbery are their favorite 

 resorts. Mr. Scott did not find this species very common at Riverside, 

 Pinal county, Arizona, in 1882. On May 5 a nest was found built in a 

 Cottonwood tree thirty-five feet from the ground, almost at the extrem- 

 ity of the branches. 



Four sets of the eggs, with the nests, of Costa's Hummer, collected 

 in the neighborhood of Banning, California, May 12 and 13, 1884, are 

 before me. The nests were built in shrubs, varying from six to twelve 

 feet in height. Two of the nests rest in slender forks, while the other 

 two are built on small twigs. The materials in these do not differ 

 essentially from those in ten nests of the Anna's Hummingbird, con- 

 sisting of soft, downy, yellowish or grayish vegetable substances, with 



