56 
BULLETIN OF THE -NUTTALL 
as contrasted with the unsuspicious nature of the Rufous-backed, is 
quite remarkable. They seem to possess a larger share than usual 
of the courage and pugnacity which is so constantly displayed in 
birds of this family. Not only do they always come off the victors 
when chance encounters take place between them and the Rufous- 
backs, but Mr. Allen has seen a pair attack and put to rout a Red- 
tailed Hawk; while, as he remarks, ^‘Sparrow-Hawks have no 
chance at all with them.” He has often seen the little fellows in 
hot chase after these latter birds, and their only care seemed to be 
to get out of the way as soon as possible of foes so determined. 
The Rufous-backed Hummer, on the contrary, frequents the 
thickets, and is always unsuspicious and readily approached. The 
different localities they affect may indicate a difference in the flow- 
ers from which they obtain their food. 
Habitat. The habitat of Selasphorus alleni seems to be con- 
fined to the coast district of California, though subsequent investi- 
gation may show that it extends its range to the northward. It 
appears to be strictly limited to the western slope of the Sierras, 
and may indeed wander but a short distance from the coast. It is 
thus very local, while the S. rufus has a very widely extended habi- 
tat. Few species, indeed, of the family range over as many degrees 
of latitude as this, which appears equally at home in the valleys 
and elevated table-lands of sub-tropical Mexico and in the less invit- 
ing regions of Southern Alaska, while it occupies in summer most 
of the intermediate ground. Specimens are in the Smithsonian 
collection from Sitka, which forms its most northern recorded local- 
ity. In the interior it appears to be of less general occurrence than 
in the region west of the Sierras, though this apparent absence is 
doubtless due in part to our lack of knowledge of the Avifauna, 
especially of the northern interior. The eastern slope of the Sier- 
ras is apparently occupied by it throughout their whole length. Mr. 
Ridgway found it in autumn in the East Humboldt Mountains, and 
Hr. Coues in Montana, and it may be said to occur over most of the 
Rocky Mountain region, either as a summer resident or as a fall 
migrant. Dr. Coues is the only one who has found it breeding in 
the interior, but I think it probable that not only the mountains 
about Fort Whipple, which formed his field of observations, but the 
mountain-fastnesses throughout the Territory of Arizona, and also 
in New Mexico, and perhaps in Southern Colorado, may furnish the 
species a summer home. Certain is it that in August this Hum- 
