THE ZONE-TAILED SAWK. 231 



lined only with green leaves of cottonwood attached to the twigs. It was 

 rather concave, and contained two eggs which differ considerably in size, shape, 

 and markings from those first found, but there can scarcely be any doubt about 

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

 was distinctly seen when flying from it, and was black, having its tail barred 

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

 absalutely free from the suspicion of being those of Urubitinga anthracina, as 

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

 smaller at one end, ground color white, with yellowish 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 smeary 

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

 The other measures 61 by 43 millimetres. It is evenly blotched with very 

 pale 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, Arizona, and found my first nest of this species on April 22, 

 1872, but as neither of the parents was procured with the eggs I did not at 

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

 pair 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 

 an57" shyness, 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 they sat at rest on some dead limb where they could be plainly 

 seen. 



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

 at that early date had dried up, leaving only 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 5 miles above my camp, near the 

 entrance to Sahuaritto Pass, it perched on a dead limb of a large cottonwood 

 tree on the west 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 principal 

 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 I might easily have done 

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

 bluish white unspotted egg. The old birds during this time were circling 

 around above the tree giving vent to shrill screams. Being some distance 

 from camp I took this egg, 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 happened. As tlie set was certainly not 



' Auk, Vol. Ill, January, 1886, pp. 64-69. 



