Plumages o/Buteo solitarius. 387 
So that it is permissible to regard tlie Buteo as the only 
truly endemic Haptor. 
From whatever quarter the lo originally found its way to 
the islands, and whatever are its nearest relatives, it is a 
true Buteo, not only in structure, but also in habits. 
It is a solitary sluggish bird, sitting most of its time 
motionless on the low branches of trees, digesting its food 
or on the look out for a fresh supply. Once on the wing, it 
is a slow but powerful flier, alternately progressing by a 
few strong beats, and using the impetus thus gained to glide 
straight ahead on outstretched wings. Whether moving in 
this fashion, or circling far above the forest, the bird might 
readily be taken by the casual observer for quite a different 
species, the Red-tailed Hawk of America. 
The food of the lo is preferably mice and small rats. 
Birds of any kind do not come amiss, when it can catch 
them, which is very rarely ; and frequently it descends to 
such humble fare as large spiders or the larvae of a sphinx- 
moth. I have found the stomachs of several individuals 
simply crammed with spiders, and the belly and thigh- 
feathers all gummed up with the silken webs and secretions. 
The lo is not a bird of the deep forest, and rarely or 
never enters its recesses, but prefers open woods in which 
to nest, and, when hunting, frequents the edges of the forest 
and the clearings. 
This Hawk breeds in spring, though apparently never 
very early, and some of the Hawaiian woodland birds are 
leading about their young ere the lo is ready to deposit its 
brown-blotched eggs in its rudely made nest. 
As a rule, this Buteo is silent, but in the love-season its 
voice is frequently to be heard, as several males contend for 
the favour of a female. Its cries are not exactly like those 
of any Hawk known to the writer, although they are un- 
mistakably Buteonine. Once mated I feel sure that the 
union is for life, and a given locality is almost invariably 
inhabited by a pair. Go the other hand, the lo rarely or 
never hunts in pairs, and the bird is, on the whole, well 
named solitarius. 
SER. VIII. — VOL. II. 2d 
