1S87. ] PnOCEKDiNGr-i OF UNITED STATES NATIOXAL AIUSETTM. 



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liluff, tlicir inteiisoly blue colors at that time eoutrastiiii;' stroni^ly with 

 their faded condition in the breeding season. 



Their habit of perching" on weeds and bushes about the plains, and of 

 hovering in the air like sparrow-hawks, as recorded by other observers, 

 wfis a striking feature of their conduct as observed at Red Bluff. They 

 did not frequent the timber belts when wintering in the valleys, but were 

 generally to be found in the open country or along the brink of the river, 

 perching upon scattered driftwood, often in conii)any with the other 

 species. 



Here we have an exchange of courtesies, Sialiaarctica being graciously 

 received at his cousin's headquarters in the valley in return for hospi- 

 tality extended to Sialia mexicana in tlie. mountains during the past 

 summer. , 



VERTICAL RANGE OF BIRDS IN NORTHERN CALIFORNIA. 



The following table illustrating the vertical range of birds in Northern 

 California is modeled somewhat after a similar one on the birds of Colo- 

 rado, by Mr. F. M. Drew {The Auk, January, 1885, p. 11), and is interest- 

 ing chiefly as showing a much lower average range than in the latter 

 State, which has a vastly greater average elevation. While there are 

 mountain peaks in California as high as any in Colorado, the upward 

 range of birds in the former State begins at sea level instead of at an 

 altitude of 3,500 feet, which is already attained upon passing within the 

 borders of the latter State. In Northern California the two great 

 ranges of mountains — the Sierra Nevada and the Coast Range, from 

 which rise peaks crowned with per[)etual snow — are sei)arated by the 

 valley of the Sacramento, a broad plain, which at its upper end, about 300 

 miles from the sea, has an altitude of but 500 feet. From there it is but 

 40 or 50 miles through the chaparal belt or "foot-hills" to the border 

 of the coniferous forests, at an altitude of 2,500 or 3,000 feet, represent- 

 ing an elevation less than the lowest laud in Colorado. 



From this it will be seen that birds are not forced into the mountains 

 as they are in Colorado, since they can i)ass between the two ranges 

 almost the entire length of the State. 



The present table of upward ranges of birds cannot claim the same 

 degree of completeness as the one with w^hich it is compared, being 

 limited, as a rule, to the observations pf one person, made at lower alti- 

 tudes. The timber-line on Mount Shasta, with an elevation of 9,000 

 feet (more than 1,000 lower than on the Rocky Mountains), being the 

 highest field of observation and the Sacramento Valley at Red Bluff 

 the lowest except at the coast, it is evident that the birds will not be 

 found to range as higii as in Colorado. 



If, in any case, species have been found at greater elevations in the 

 region in question than those indicated by my own observations, the 

 former altitudes are substituted. This is, however, the exception. 



