xxii Birds of Colorado 
rufus, Corvus c. sinuatus, Cyanocephalus cyanocephalus, 
Passericulus s. alaudinus, Spizella p. arizone, Piranga 
ludoviciana, Vireo g. swainsoni, Lanivireo s. plumbeus, 
Dendroica auduboni, D. nigrescens ?, Oporornis tolmiet, 
Wilsonia p. pileolata, Cinclus m. unicolor, Sitta c. 
nelsoni, Penthestes a. septentrionalis, Myadestes town- 
sends, 
(F) Birds chiefly confined during the breeding season 
to the mountains, between 8,000 and 11,500 feet—39 in 
number, or 17 per cent. :— 
Mergus americanus ?, Clangula islandica, Histrionicus 
_histrionicus, Gallinago delicata, Dendragapus obscurus, 
Lagopus leucurus (up to 13,500 feet), Falco c. richardsoni, 
-Cryptoglaux acadicus, Picoides a. dorsalis, Sphyrapicus 
-v. nuchalis, S. thyroideus, Cypseloides borealis, Aéro- 
nautes melanoleucus, Nuttallornis borealis, Empidonax 
dificiis, E. hammondi, E. wrighti, Cyanocitta  s. 
sdiademata, Cractes c. capitalis, Nucifraga columbiana, 
Hesperiphona v. montana, Pinicola e. montana, Car- 
podacus cassini,  Leucosticte australis, Zonotrichia 
.leucophys, Junco caniceps, Melospiza lincolni, Oreospiza 
chlorura, Tachycineta t. lepida, Dendroica gracie, Anthus 
rubescens (to 13,000 feet), Certhia f. montana, Sttta 
canadensis, S. pygmea, Penthestes gambeli, Regulus s. 
olivaceus, R. calendula, Hylocichla u. swainsoni, H. g. 
-auduboni. 
ACKNOWLEDGMENTS. 
Tam deeply indebted to Mr. Charles E. Aiken of Colorado 
Springs, for constant help and advice during the prepara- 
tion of this work. As has already been stated, the descrip- 
‘tions are all based on the large collection of Colorado birds 
made by him, and now the property of Colorado College ; 
“but apart from this, I have been able through his kindness 
