TUE ZONE-TAILED HAWK. 233 



based on Stephens's and Werner's identification, I natnrally came to the con- 

 clusion that the eg:g's taken liy me in Arizona were clearly referable to the 

 Mexican Black Hawk and none other. 



Even Dr. Mearns's subsequent article on these two species published in 

 the Auk (Vol. in, January, 1886, pp. (iO-73), did not shake my faith in my cor- 

 rect identification of these eggs, after having- examined specimens of the two 

 species. This was further strengthened by a letter from Mr. William Lloyd, 

 who Avrote me that he had found a nest of Unibitbiga antJiracbia on April 13, 

 1890, in Presidio County, Texas, and having shot the female, he found a fully 

 developed egg in her oviduct. This was badly broken; he sent me the pieces, 

 however, and Mr. ¥. A. Lucas kindly restored the specimen very skillfully. 

 This egg was likewise bluish white in color, unspotted, and measured 54 by 42 

 millimetres; it was in fact an exact counterpart of Dr. Mearns's egg of Bideo 

 abbreviatus, and of my supposed eggs of Unibitinga anthracina. I was naturally 

 anxious to see the parent, and this, on examination, proved to be a Zone-tailed 

 Hawk. 



I am satisfied now that Dr. Mearns was perfectly right in his surmise, 

 that the birds found by me breeding in Arizona in 1872 were really Buteo 

 abbreviatus as I originally supposed, and I am equally certain that some of 

 the notes taken by me at the time, and which will be quoted in their proper 

 place, are positively referable to Unibitinga anthracina, and show clearly that I 

 met with both species. 



The Zone-tailed Hawk is pretty generally distributed over the greater por- 

 tion of Arizona during the breeding season, and is not especially rare. A pair 

 or two may be found iidiabiting all the larger cottonwood groves in the Terri- 

 tory, anfl i* seems to be especially partial to such trees to nest in, thev usually 

 Ijeing found only along the banks of the few streams in this poorl}' watered 

 country. According to Dr. Mearns, its food consists of lizards, frogs, and fishes, 

 but small mammals are. undoubtedly also included in its bill of f;ire. 



It usually makes its appearance from the south in the beginning of April, 

 and but a single brood is raised in a season. Both sexes assist in incubation, 

 M-hieli, as with our larger Raptores, lasts about four weeks. The eggs varv 

 from one to three in number, usually two, and seem to be for the most pai-t 

 imspotted. They are oblong oval in shape, pale bluish white in color, and the 

 shell is rather smooth and finely granulated. 



According to Messrs. Stephens and Werner the eggs are occasionally 

 spotted, and I. have no reason to doubt their identification. Nidification 

 commences in the latter pai't of April and lasts through May. 



The egg taken by Dr. Mearns near New River, Arizoiia, on May 16, 

 1885, about which there can be no possible doubt as to its identification, 

 both parents being shot at the same time, and which is now before me, 

 measures 54 by 43 millimetres, and is figured on PI. 7, Fig. 6, as the 

 type of this species, having been kindly loaned to me by the American 

 Museum of Natural History, New York City, New York, to which collec- 



