THE ZONE-TAILED HAWK. 231 



lined only witli green leaves of Cottonwood attached to the twigs. It was 

 rather concave, and contained two egga whicli diflfer con-<iderably in size, shape, 

 and markings from those hrst fonnd, Ijnt there can scarcely be any donbt about 

 the identification, for the female was .shot close to the nest, wliile the other bird 

 was distinctly seen wlien flying from it, and was black, ha^'ing its tail barred 

 with white below. Perhaps, however, it is safest to say that these eggs are not 

 absolutely free from the suspicion of being those of Uruhltinga anthacbia, as 

 the parent seen to leave the nest was not .shot. They are oval, considerably 

 smaller at one end, ground color white, with yello\vish weather stains in spots. 

 One measures 63 by 45 millimetres. It is finely sprinkled with dark sepia- 

 brown specks, and a few paler brown and lavender spots, having a smears' 

 granular appearance. All the marks are most numerous at the large extremity. 

 The other measm-es 61 b}" 43 millimetres. It is evenly blotched wnth very 

 })ale yellowish brown and lavender. Both contained large embryos and were 

 emptied of their contents with difficulty." ' 



Several years previous to these accounts I met with the Zone-tailed Hawk 

 on Rillitto Creek, Ai'izona, and found mv first nest of this .«»pecies on April 22, 

 1872, but as neither of the parents was procm-ed witli the eggs I did not at 

 the time describe them. Thev were summer residents only, and I saw the first 

 })air of "Black Hawks" on April 4, 1872. On the 6th I noticed another pair, 

 which were just commencing to build a nest in a tall Cottonwood tree, in a 

 large grove about a mile above my camp. Neither pair of these birds showed 

 any shjoiess, allowing me to approach closely to them; and, with the assist- 

 ance of an excellent field glass, I took careful observations of them at different 

 times while thev sat at rest on some dead limb where thev could be plainlv 

 .seen. 



On April 22, while riding along the banks of Rillitto Creek, which even 

 at that early date had dried up, leaving onlv a stagnant water hole here 

 and there, I noticed one of these Black Hawks flying up the creek bed, and 

 being at leisure I followed it. Some h miles above my camp, near the 

 entrance to Sahuaritto Pass, it perched on a d'_^ad limb of a large cottonwood 

 tree on the we.st side of the creek. On nearing this, I saw an old and bulky 

 nest placed in a fork close to the main trunk of the tree, about 40 feet up, and 

 the mate of the bird I had been following sitting on the nest. As my princij^al 

 object was to study the nesting habits of our birds, as well as to collect their 

 eggs, I refrained from shooting either of them, which 1 might easily have done 

 at the time. On climbing to the nest I found it contained but a single pale 

 bluish white nn.spotted egg. The old liirds during this time were circling 

 around aboA'e the tree g-iving- vent to shrill screams. Being some distance 

 fidm t;amp I took this eg'g, and had not moved more than a hundred yards 

 away from the tree before one of the birds, presumably the female, settled 

 on the nest again as if nothing had hajjpened. As the set was ceitaiidy not 



' Auk, Vol. Ill, January, le«6, pp. 64-69. 



