WHITE-EARED HUMMINGBIRD 453 



vernal equinox and the June solstice, when the vast majority of 

 birds of all kinds raise their young, nests of the hummingbirds are 

 unknown at higher elevations. During the season when the hum- 

 mingbirds breed, the only other bird whose nests I have found, at 

 altitudes in excess of 7,000 feet, is Diglossa laritula^ an aberrant 

 honeycreeper, which, like them, sucks the nectar of flowers. 



Just as many of the plants that blossom during the dry season 

 anticipate the return of bright weather and open their earliest 

 flowers during the gloomy days of the later part of the rainy season, 

 so the male white-eared hummingbirds prepare for their courtship 

 well in advance of the cessation of the rains. By the end of August 

 1933, some of the male white-ears, on the mountains above Tecpan 

 in west-central Guatemala, had chosen the positions they would 

 occupy during the following months, and from time to time sounded 

 in a tentative fashion the clear little notes that advertise their pres- 

 ence to the females. As September advanced with increasing mist 

 and rain they lapsed into silence, but with the advent of October 

 they became vocal again, and some tinlvled from the same bushes 

 where I had first heard them a month earlier. 



As I roamed the bushy mountainsides and the open oak woods, it 

 soon became clear to me that the male white-ears were not distributed 

 uniformly or at random over the territory suitable to them but had 

 congregated into definite groups which I came to call "singing assem- 

 blies." The largest of these assemblies that I discovered was made 

 up of seven birds, whose perches were in the pine and oak trees sur- 

 rounding an irregular open pasture. This group was very much 

 spread out, with the two most distant individuals about 600 feet 

 apart and out of hearing of each other (unless the hummingbirds' 

 ears are sharper than my own) ; but each member of the assembly 

 could certainl}^ hear the calls of two or more of his neighbors. An- 

 other assembly consisted of five birds, scattered among tall raijon 

 bushes that had taken possession of an abandoned pasture, the birds 

 so spaced that each was about 90 to 100 feet from his neighbors. 

 Other assemblies contained three or only two white-ears. Sometimes 

 the birds perched as close as 60 feet from each other. Between these 

 groups of hummingbirds were considerable stretches of similar ter- 

 rain where one listened in vain for their reiterated notes. 



Scattered here and there, however, were lone males, which re- 

 mained aloof from the assemblies. One of these made his head- 

 quarters in a raijon bush beside the road, and here I frequently met 

 him, perched on a dead twig and tinkling persistently. Another, 

 with a weak, plaintive little voice, called from a low perch on a bush 

 in an overgrown pasture, beyond hearing of all others of his kind. 



The male white-ears sometimes chose low perches in the midst of 



