The Bluebird selects as a suitable place for its nest a hollow in the decayed trunk of a tree, or boxes prepared for its use. Their early arrival enables them to select their own site. The nest is loosely constructed of soft materials, such as fine grasses, sedges, leaves, hair, feathers, etc. These are rarely so well woven together as to bear removal. The eggs are usually five and sometimes six in number. There are usually three broods in a season. Before the first brood are able to provide for themselves, the female repairs her nest and commences incubation for a second family. The young birds are, however, by no means left to shift for themselves. The male bird now shows himself as devoted a parent as in the earlier spring he had proved himself an attentive mate. He watches over the brood even after the second family appears and claims his attention. We often find him dividing his cares in the latter part of the season with two broods, and at the same time supplying his mate with food, and occasionally taking her place on the nest. The eggs of the Bluebird are of a uniform pale blue, measuring about .81 of an inch in length by .62 in breadth. In Guatemala is found a local race differing in its lighter under colors and in the greenish tinting of its blue (_S. azurea_). The _S. sialis_ is also found in the more open districts of the elevated regions where it is numerous. It is there known as “_El azulejo_.” Sialia mexicana, SWAINS. CALIFORNIA BLUEBIRD. _Sialia mexicana_, SW. F. B. Am. II, 1831, 202.—SCLATER, P. Z. S. 1856, 293 (Cordova): 1857, 126 (California); 1859, 362 (Xalapa).—IB. Catal. 1861, 11, no. 66.—BAIRD, Birds N. Am. 1858, 223; Review, 63.—COOPER & SUCKLEY, P. R. R. XII, II, 1859, 173.—COOPER, Birds Cal. 1, 28. _Sialia occidentalis_, TOWNS., AUD.; _Sialia cæruleocollis_, VIGORS. Figures: AUD. B. A. II, pl. cxxxv.—IB. Orn. Biog. V, pl. cccxciii.— VIGORS, Zoöl. Beechey’s, Voy. 1839, pl. iii. SP. CHAR. Bill slender. Head and neck all round, and upper parts generally bright azure blue. Interscapular regions, sides and fore part of the breast, and sides of the belly, dark reddish-brown. Rest of under parts (with tail-coverts) pale bluish, tinged with gray about the anal region. Female duller above; the back brownish; the blue of the throat replaced by ashy-brown, with a shade of blue. Length, 6.50; wing, 4.25; tail, 2.90. _Young._ Tail and wing as in adult; head, neck, back, and breast, dull brown; each feather, except on the crown, streaked centrally with white. HAB. Western United States, from the Rocky Mountains to Pacific. Not noticed on the Missouri plains, Central British America, or at Cape St. Lucas. Found at Xalapa and Cordova, Mex., SCLATER. Popocatapetl (Alpine region), SUMICHRAST.