Dr. Merriam found the Broad-tails very abundant in the balsam and pine belts of the San Francisco Mountains of Arizona, where their principal food plants were the scarlet trumpet flower and the large blue larkspur. Of their habits he says, “They wake up very early in the morning and go to water at daylight, no matter how cold the weather is. During the month of August, and particularly the first half of the month, when the mornings were often frosty, hundreds of them came to the spring to drink and bathe at break of day. They were like a swarm of bees, buzzing about one’s head and darting to and fro in every direction. The air was full of them. They would drop down to the water, dip their feet and bellies, and rise and shoot away as if propelled by an unseen power. They would often dart at the face of an intruder as if bent on piercing the eye with their needlelike bill, and then poise for a moment almost within reach before turning, when they were again lost in the busy throng. Whether this act was prompted by curiosity or resentment I was unable to ascertain.” It seems strange and unnatural that so delicate a bird and one so highly colored should frequent localities where periods of low temperature are common. Yet the Broad-tailed Hummingbird prefers high elevations and has been known to nest at an altitude of eleven thousand feet, and it seldom breeds at places lower than five thousand feet. The males leave for their winter homes very early in the season. Usually this migration takes place very soon after the young birds leave their nests. Mr. Henshaw attributes this movement of the males to the fact that their favorite food plant, the Scrophularia, begins to lose its blossoms at this time. He says: “It seems evident that the moment its progeny is on the wing and its home ties severed, warned of the approach of fall alike by the frosty nights and the decreasing supply of food, off go the males to their inviting winter haunts, to be followed not long after by the females and young. The latter, probably because they have less strength, linger last, and may be seen even after every adult bird has departed.” [Illustration: BROAD-TAILED HUMMINGBIRD. (Selasphorus platycercus.) Life-size. FROM COL. CHI. ACAD. SCIENCES.]