164 
THE CONDOR 
Von. XI 
usually found in small flocks. The greater part of the specimens I referred to P. a. 
atricaftillus, tho they do not agree closely with eastern specimens. The greater 
part of them are intermediates, verging toward the western form, s eft ten trio n a Us , 
and in many cases it is difficult to decide where they belong. About eighty per 
cent can be referred to the eastern variety, and this is apparently the dominant 
breeding bird. 
68. Penthestes atricapillus septentrionalis. Long-tailed Chickadee. Several 
birds of this variety were taken, and they appear to be of regular occurrence in 
this vicinity, as mentioned in the notes under the preceding variety. Ninety skins 
were made of the two varieties. 
69. Regulus calendula calendula. Ruby-crowned Kinglet. On several morn- 
ings I noticed one or two of these birds feeding in some willows near the tent, and 
one immature female was taken September 18, 1908. None were taken during the 
preceding year. 
70. Hylocichla mustelina. Wood Thrush. One taken September 20, 1907, 
was the only one seen. The rest had already gone south in the fall migration. 
71. Hylocichla fuscescens salicicola. Willow Thrush. Two of these birds 
were taken, one September 12, and one September 16, 1908. They were found 
in rather open thickets, one being taken on the side-hill, and the other in the ravine 
near camp. I have one other specimen in my collection, taken September 28, 
1907, in this same locality, and these three constitute the only records for the state 
to my knowledge. I have been confidently expecting to secure them sooner or 
later, however, as they have been taken so much further east. 
72. Hylocichla ustulata swainsonii. Olive-backt Thrush. A single one taken 
September 17, 1908, was the only one seen. Thrushes, other than robins, were 
rare during both years, and only a few were taken. 
73. Planesticus migratorius migratorius. American Robin. During 1907 
robins were more abundant than the succeeding year, and were found in the thick- 
ets on the hillsides, and along the creeks. Some of those taken were still in the 
spotted juvenile plumage, but most of them had almost completed the molt to the 
adult plumage, some of the birds showing a full winter dress. All those taken the 
second year were much more advanced in molt, and in better condition than the 
year previous. 
74. Sialia sialis sialis. Bluebird. Common in flocks of from six to a dozen 
along the country roads. These flocks markt family groups, and frequently con- 
tained spotted individuals and others just molting out of the juvenile plumage. 
Twenty-five specimens were taken. 
Denver , Colorado. 
CLIFF CLIMBING FOR PRAIRIE FALCON EGGS 
By GEORGE RICHARDS 
WITH TWO PHOTOS 
C LIFF climbing can hardly be termed a sport in spite of its many thrills and 
pleasures. This is especially true when the climbers are amateurs and 
equipment limited. Even when a rare or interesting set of eggs leads one to 
make the attempt, his nerve suffers a queer sensation when he looks down the one 
