APPENDIX N N. 
1305 
Below is appended a full list of the Pacific province forms that find th«ir eastern 
limit along the eastern slope of the main chain.* 
I. Species limited by eastern slope: 
1. Zonofrichia coronata. Fall migrant. 
2. Passerella var. megaryncha. Summer resident. 
3. Pipilo var. oregonus. Resident. 
4. Cyanura var. frontalis. Resident 
5. Cyanocitta var. caUfornica. Resident. 
6 . Picus albolarvatus. Resident. 
7. Sphyrapicus ruber. Resident in small numbers; fall migrant. 
8. Oreortyx picta. Resident. 
II. The following Pacific province species find their limit as above in the breeding 
season, but during the migrations, especially in the fall, they occur more or less fre¬ 
quently at points at variable distances to the eastward : 
1. Turdus pallasii var. nanus. Migrant. 
2. Turdus swainsoni \ ar. ustulatus. Summer resident. 
3. ? Thryothorus bewickii var. spilurus. Resident. 
4. Troglodytes hycmalis var. pacificus. Winter resident. 
5. Helminthopliaga celata var. lutescens. Summer resident. 
6. Myiodioctespusillus var. pileolaius. Summer resident. 
7. Melospiza melodia var. heermanni. Resident. 
8. Melospiza melodia var. guttata. Perhaps accidental. One specimen in West Hum¬ 
boldt Mountains in fall. (Ridgway.) 
9. Junco oregonus. Resident. 
10. Zoiwtrichia leucophrys var. intermedia. Summer. 
11. t Ageelaius phamiceus var. gubernator. Summer. 
12. t Nepocoetes niger. Summer. 
13. t Chcetura Vauxii. Summer. 
14. Selasphorus rufa. Summer. 
As noticed above, the fauna of the plains and valleys to the east of the main chain 
is, in respect to its summer residents, indistinguishable from that of the middle pro¬ 
vince. 
As showing the sharpness with which the line of demarkation is drawn by the Sierra 
Range we are able to note but two species, which may be considered as characteristic¬ 
ally belonging to the middle province, which, in their range westward, intrude beyond 
the limit assigned and reach into the mountains. These are Carpodacus frontalis and 
Pica melanoleuca var. hudsonica. The first is numerous about Lake Tahoe, but does not, 
so far as I could ascertain, reach to the west of the divide. Pica hudsonica scarcely 
finds its way into the range, but is mostly limited by the foot-hills. A few individuals, 
however, were noticed by us on the borders of Tahoe. 
Of the specimens procured along the eastern slope during the season a number have 
proved of especial interest, as illustrating the differentiation which takes place in a 
species or variety when found at a point remote from the locality or region where its 
peculiarities attain their maximum development, and which consequently may be con¬ 
sidered its true home. 
The eastern slope of the Sierras, though belonging, as has been shown, to the Pacific 
province, occupies a somewhat intermediate position between the Pacific and Middle 
provinces, and, as it differs climatically more or less from either regim, its birds might 
be supposed to indicate to some extent, in plumage or otherwise, the changes under¬ 
gone in the conditions of environment. Such has been found to be true. This is best 
illustrated in the cases of several birds that are represented by different varieties in 
the two provinces. In all such instances, while they are seen to partake more largely 
of the characteristics pertaining to the Pacific forms, they are yet, to a very apprecia¬ 
ble extent, intermediate, and, when compared with their respective types from the west 
coast, will be seen to divaricate directly toward the conditions distinguishing the mid¬ 
dle province forms. Thus the Californian jays ( Cyanocitta Jloridana var. caUfornica) of 
the eastern slope not only have smaller bills and feet than coast examples, but their 
colors throughout are decidedly lighter, thus approaching in characteristics the var. 
woodhousei of the interior, which in its typical form begins to occur only in the east¬ 
ern part of Nevada. Similar differences, though not carried to the same extent, are 
found in the Steller’s jay, in the variety known as var. frontalis, which, though con¬ 
fined to the Sierras, becomes somewhat lighter colored, with smaller bill, at its eastern 
limit than in the Californian coast range on the w r est. 
* For a number of these, as w r ell as for indications of the character of their occur¬ 
rence, I am indebted to the admirable list of Mr. Ridgw r ay ; vide Bull. Essax Institute, 
vol. 6, No. 10; vol. VII, Nos. 1 and 2; and also in several instances to verbal notes fur¬ 
nished by him. 
t These three birds breed in the valleys adjoining the mountains. 
