In the Huachuca Mountains of Arizona, I found but one nest of the black-throated gray warbler. It was 5 feet up in the main crotch of a small oak growing on a steep slope on the side of a branch of Ramsey Canyon; the slope was sparsely covered with scrub oaks and other bushes, with a scattering of tall pines; the nest was so well concealed that I could not get a clear photograph of it. Howard (1899) found three nests in these mountains in upright forks of oak saplings, and says: "I found other nests, some placed in large white oaks and some in sycamores and have known the birds to build high up in pines." One of his nests from these mountains, in the Thayer collection, was found only 18 inches up in a young fir tree in a thicket; lying against the main stem, it was supported, surrounded, and well concealed by live twigs. Four other nests in this collection, were all taken in the Huachuca and Chiricahua mountains from oaks at heights ranging from 6 to 16 feet above ground. All much alike, their decidedly gray appearance makes them less visible among the gray branches. They are made of light gray, old, shredded stems of dead weeds and grasses, very fine gray plant fibers and a few dead leaves, bits of string, and thread, all firmly bound with spider's web and decorated with numerous bits of spider cocoons. They are lined with fine brown and white hairs and small, soft feathers. In New Mexico, Jensen (1923) reports two nests in piñon pines; one was 3 feet and the other 5 feet above ground. _Eggs._--From 3 to 5 eggs, usually 4, constitute a full set for the black-throated gray warbler. These are ovate to short ovate and are only slightly glossy. The ground color is white or creamy white and is speckled, spotted, and sometimes blotched with "chestnut," "auburn," "bay," or "russet," occasionally with "mummy brown," with underlying spots of "light brownish drab," or "light vinaceous drab." The spots are usually concentrated at the large end, forming a loose wreath, with the drab markings frequently in the majority. Some eggs are only lightly speckled, while others are boldly marked. The measurements of 50 eggs average 16.5 by 12.5 millimeters; the eggs showing the four extremes measure =18.2= by 12.3, 18.1 by =13.1=, =14.6= by 12.9, and 16.2 by =11.6= millimeters (Harris). _Young._--The period of incubation does not seem to have been recorded for this warbler. It is probably performed by the female entirely, but both parents share in the feeding of the young. Information on this subject is scanty.