62 



NORTH AMERICAN BIRDS. 



Genus SIALIA, Swainson. 



Sialia, Swainson, Zool. Jour. Ill, Sept. 1827, 173. (Type Molacilla sialis, L.) 



G-EN. Char. Bill short, stout, broader than high at the base, then compressed ; slightly 



notched at tip. Rictus with short bristles. 

 Tarsi not longer than the middle toe. Claws 

 considerably curved. Wings much longer than 

 the tail; the first primary spurious, not one 

 fourth the longest. Tail moderate ; slightly 

 forked. Eggs plain blue. Nest in holes. 



The species of this genus are all well 

 marked, and adult males are easily 

 distinguishalile. In all, blue forms a 

 prominent feature. Three well-marked 

 Sialia sialis. specics are known, with a fourtli less 



distinct. The females are duller in 

 color than the males. The young are spotted and streaked with white. 



Synopsis of Species. 



Co>r.MON Characters. Rich blue above, duller in the female. Beneath reddish 

 or blue in the male, reddish or light drab in the female. Young with wings and 

 tails only blue, the head and anterior parts of body with numerous whitish spots. 

 A* Breast reddish^ o?" chestnut. 



1. S. sialis. No chestnut on the back ; thz'oat reddish; abdomen and 

 crissum white. 



Blue of a rich dark purplish shade. Tail about 2.75. Hab. East- 

 ern Province United States, Cuba, and Bermudas . . var. sialis. 



Blue of a greenish shade. Tail about 3.20. Hah. East Mexico 

 and Guatemala ........ var. azurea.^ 



^ 2. S. mexicana. Chestnut, in greater or less amount, on the back ; 

 throat blue ; abdomen and crissum blue. Hab. West and South ]\Iid- 

 dle Province United States, south to Jalapa, Cordova, and Colima. 

 B. Breast blue (light drab in 9 )• 



3. S. arctica. Entirely rich greenish-blue ; abdomen white. Hab. 

 Middle Province United States ; Fort Franklin, British America. 



Sialia sialis, Baied. 



EASTERN BLUEBIRD. 



Motacilla sialis, Linn. S. N. 1758, 187 (based on Catesby, I, pi. xlvii). Sialia sialis, 



Baird, Birds N. Am. 1858, 222; Rev. 62. — Boardman, Pr. Bost. Soc. 1862, 124 



(Calais, Me. ; very rare). — Dresser, Ibis, 1865, 465 (Texas, winter). — Samuels, 

 B. N. Eng., 175. Sialia wilsoni, Swainson, Zobl. Jour. Ill, 1827, 173. — Cab. Jour. 



1858, 120. — GuNDLACH, Cab. Jour. 1861, 324 ; Repertorio, 1865, 230. — Jones, 



^ S. azurea, Baird, Rev. Am. Birds, 1864, 62. (aS*. azurca, Swainson.) 



