Chestnut-backed Bluebird 527 



Eastern Bluebird, Sialia sialis. 



A.O.U. Checklist no 766— Colorado Records — Aiken 72, p. 19-t ; 

 Tresz 81, p. 284 ; Nash 83, p. 46 ; Beckham 85, p. 140 ; Thorne 86, p. 

 489 ; Cooke 97, pp. 126, 170, 223 ; H. G. Smith 96, p. 76 ; 08, p. 191 ; 

 Dille 00, p. 88 ; Henderson 03, p. 237 ; 09, p. 242. 



Description. — Male — Above bright ultramarine-blue, becoming dusky 

 on the imier webs of the wing-feathers ; sides of the head dull blue ; 

 below rufus-brown, white from the centre of the abdomen to the under 

 tail-coverts ; iris dark brown, bill and legs black. Length 6-25 ; 

 wing 3-80 ; tail 2-50 ; culmen -48 ; tarsus -75. 



The female is blueish-grey above, brightening to blue on the rump 

 and tail ; longer wing-feathers edged with grey or white, as is abo 

 the outer web of the outer primary. In the fall the bright blue of the 

 male is obscured by a brownish wash. A young bird is dusky above, 

 spotted and streaked with white or pale buffy ; only the wings and 

 tail show some blue, below dull white, the edges of the feathers marked 

 with brown, producing a squamated appearance. 



Distribution. — Breeding from Montana, Manitoba and Nova Scotia, 

 south to Florida and Texas ; wintering in the southern half of its 

 breeding range. 



The Eastern Bluebird is by no means an uncommon summer resident 

 on the eastern plains of Colorado, and has even been found nesting 

 in the foothills of Boulder co. by Gale (Cooke). It was first definitely 

 recorded from the State by Holden, who took a specimen near 

 Fountain, El Paso co. (Aiken). It has since been noticed at Julesburg, 

 Wray, Kit Carson, Holly and Prowers, along the eastern borders of 

 the State by Smith (08) and Ferrill, and at Limon by Aiken, while 

 Dille found it nesting at Denver, and Thorne at Fort Lyon. It arrives 

 in AprU — Pueblo, April 6th, Nash ; and has been seen as late as 

 September 6th at Denver, by H. G. Smith (96). 



Habits. — ^A nest found by Dille was built in a nest- 

 box which had been used by the Arctic Bluebird pre- 

 viously the same season. A clutch of five eggs was 

 taken on June 21st ; Gale's nest contained four fresh 

 eggs on June 18th, and was found on a ranch near Gold 

 Hill, in Boulder co. 



Chestnut-backed Bluebird. Sialia mexicana hairdi. 

 A.O.U. CheckHst no 767a — Colorado Records — Allen 72, p. 148 ; 

 Aiken 72, p. 194 ; Trippe 74, p. 229 ; Tresz 81, p. 284 ; Allen & Brewster 

 83, p. 153 ; Drew 85, p. 15 ; Beckham 85, p. 140 ; 87, p. 125 ; Morrison 



