348 



SHPvIEKIXG BIRDS — STPJSORES 



sunset. It is very probable that they winter about the canons,, though I 

 saw none at Fort Mojave until May, probably stragglers from their favorite 

 mountains. On the 7th of June, near the head of the Mojave Eiver, I found 

 a few of them about some lofty granite cliffs, and l:)y watching them closely 

 succeeded in shooting one as it came sweeping towards me al)0ut sunset as 

 if about to ily in my face. Their flight is exceedingly swift and changeable, 

 resemljling that of the Chaiura, and they are probably the most difficult 

 of all our birds to shoot. Tlieir cry when flying is low but harsh, and 

 sound.s much farther off than the actual distance of the bird. They also 

 utter a harsh croaking noise. 



About twelve miles north of San Diego, I again found them rather 

 numerous about some high rocky fluff's close to the sea-shore. They \\'ere 

 there March 22d, and may have been about for a month previously, but 

 generally fly so high during the day tliat they are first betrayed by their 

 harsh twitter when scarcely percepti! >le in the zenith. Occasionally they 

 dart off like lightning for several miles and back, as if it were only a slight 

 curve in their course. Sometimes tliey sweep for a moment near the 

 ground, and the next disappear in the sky above. They doubtless build in 

 the crevices of the lofty rocks about which tliey \\\e, but, though I have 

 looked for their nests, I have not been able to find them. 



Genus NEPHCECETES, Baird. 



NepJiwcetes, B.URii, P. Kcp. IX. Binls, 18")S, 142. 



Gen. Ch.\r. Tail rather less tlian half the wings ; (jnite (lec])ly forked ; the feathers 

 obtusely acuminate ; the shafts scarcely stifTened. First quill longest. Tarsi and toes 

 completely bare, and covered with naked skin, without distinct indications of scutells. 



