248 LIFE HISTORIES OF NORTH AMERICAN BIRDS. 



be seen unless closely examined. The egg measures 55 by 41 millimetres, 

 and the ground color is a pale greenish white. The egg is ovate in .shape 

 and it is figured on PI. X, Fig. 7. 



I have been unable to gather any information additional to that already 

 given. From the foregoing it would appear that these Hawks commence 

 laying from the last half of March to the beginning of May, and that from 

 one to three eggs constitute a set. 



84. Urubitinga anthracina (LICHTENSTEIN). 



MEXICAN BLACK HAWK. 



Falco anthracinus LICHTENSTEIN, Preis-Verzeichniss, 1830, 3. 

 Urubitinga anthracina LAFRESNAYE, Review Zoologique, 1848, 241. 



(B , C , R 444, C 528, U 345.) 



GEOGRAPHICAL RANGE : Tropical America in general, north to central Arizona, 

 and the Lower Rio Grande Valley in Texas. 



As far as is known at present, the breeding range of the Mexican Black 

 Hawk is confined to central and southern Arizona, and the Lower Rio Grande 

 Valley in Texas, and it does not appear to be a common species anywhere 

 within our borders. 



While encamped on Rillitto Creek, 7 miles northeast of Tucson, in the 

 spring of 1872, I first noticed this species on April 4, apparently just return- 

 ing to their summer homes. Knowing but little about our birds I supposed 

 it at first to be one of the dark forms of Buteo swain*oni, then known as 

 Buteo insignatus, and I subsequently wrongly identified it as Buteo alilnr- 

 viatus. My notes taken on that day read as follows: "Saw a pair of Hawks 

 to-day which I take to be of this species (No. 21, Buteo itisiynatttx, Baird's 

 Cat., 1859). They were quite tame, and let me come within 30 feet. I 

 should not exactly call them black, but rather a dark and uniform slate 

 color, with the wings a little darker, possibly. The cere and bill appeared 

 to be yellow, also the feet, and th tail was banded by a white stripe at 

 the end. One of them as it flew off appeared to have every feather of the 

 upper parts of the breast edged with ferruginous. The pair kept circling 

 around and over me, uttering at the same time repeated cries, exact counter- 

 feits of the piping in the spring of Numcnius Ungirostris. I could easily have 

 shot both, but they evidently ineant to build in the neighborhood." 



The ferruginous edgings of the feathers of the breast, noticed by me, 

 clearly indicate that the specimen in question is referable to this species, 

 being a bird still in the immature plumage, and, as far as known, this plumage 

 is not found in Buteo allreviatus. 



Col. A. J. Grayson, in his "Notes on the Birds of Northwestern Mexico," 

 says of this species: "Common at all seasons, usually found about the esteros 

 and marshes near the seacoast, s ibsisting chiefly upon land crabs." 



