Habits of White-Eared Hummingbird in Northwestern Mexico

Abstract

AN airplane flight from Parral, Chihuahua, to a natural mountain meadow on Mount Mohinora led to the discovery of our first completed nest of the White-eared Hummingbird, recently named by Mr. Griscom Hylocharis leucotis borealis. Shortly after sunrise we had climbed to an elevation of twelve thousand feet and were crossing an exceedingly rugged area of sharply contoured peaks and profound canyons. About fifty miles southwest of Parral we caught the reflected sun a small lake, nestled two thousand feet below us at the base of a sheer cliff. The only body of water observed on the entire flight, it filled a basin the center of this remote and inaccessible country. Obviously an excellent site for a major collecting station, it was immediately chosen by the author as a future base. Two months later, Chester Lamb made an arduous journey to the shore of this lake, Laguna Juanota, and collected there for an entire month. On August 12, 1937, he obtained the first nest that he had found of the White-eared Hummingbird. In our six years of zoological explorations northwestern Mexico we have collected only four nests of this species. Two of these were complete and taken by Mr. Lamb, the third was found on the ground by the author and Arthur Barr, and the fourth had only its foundation laid, when the author discovered it. In his journal Mr. Lamb states that the Laguna Juanota nest was found in a small oak, six inches diameter and twenty-five feet tall, growing a grove of the same on the north hillside of a rocky butte at the lake. It was saddled on a twig among the leafy extremities of a branch two feet from the trunk. The nest is composed almost entirely of a buffcolored plant-down, the only exceptions consisting of one small oak twig woven loosely to the bottom of the nest and greenish-gray lichens ornamenting the exterior portion. Measuring 1 by 118 inches on the inside, it has no other lining except the plant-down. The outside measurements are 1% by l inches. It contained one fresh egg, now with the nest the Moore Collection. The second nest was found May 23, 1938, lying on the ground among pines and oaks of Rancho Batel at the top of a mountain range, where it reaches 6,300 feet elevation southeastern Sinaloa; apparently it had been attached to a limb of the oak tree above it. It resembles closely the first nest, except that two oak catkins have been woven into the sides and the lichen decorations are more abundant. In spite of the fact that it is twice as large as the Laguna Juanota nest, I have no doubt as to the identity, be-