KIEFFER'S HUMMINGBIRD 437 



found, were betrayed by the birds' darting off as I passed within a 

 few yards of them. The instinct that leads the birds to build a nest 

 to blend so well with its setting lacks fulfillment in a corresponding 

 instinct to utilize this advantage by remaining motionless. Perhaps 

 at the approach of really formidable enemies other than man the fe- 

 male does remain motionless on her nest; but when most small 

 creatures, lizards or birds even many times her size, venture too near, 

 she merely darts at them and usually puts them promptly to flight. 

 Individual birds, however, differ greatly in the closeness with which 

 they cover their eggs and young. One female, the closest sitter of 

 all I found, whose nest was built in a young lime tree in a nursery 

 where men were frequently at work, would allow me to approach 

 within arm's length before deserting, to return within a few minutes 

 and settle down on her eggs directly before me if I waited quietly at 

 this distance. 



I could scarcely have desired a nest located more conveniently for 

 study than the first of this species I ever found. I was at the time 

 engaged chiefly in work with the microscope in a little frame build- 

 ing that served as office and laboratory at the now abandoned ex- 

 periment station of the United Fruit Co. beside the great Chan- 

 giiinola Lagoon, 20 miles from Almirante, Panama. On the after- 

 noon of December 19, I raised my head from my work and noticed a 

 hiunmingbird, of a kind still unknown to me, perched on the petiole 

 of a ramie plant {BoehmeHa nivea) just outside the window, scarcely 

 3 yards from where I sat and separated from me only by a screen. 

 An oddness in her manner of perching attracted my attention, and, 

 looking more intently, I perceived something light colored almost 

 hidden beneath her. When she flew off, I went out to examine her 

 perch and found there a little tuft of plant down, fastened in the 

 angle between the hairy petiole and the stem with cobweb, a piece of 

 white thread, and several hairs from cattle, which grazed all about 

 the small enclosure. During the succeeding days, as I sat ^t my 

 work table poring over bits of banana tissue, Amazilia labored stead- 

 ily at her growing nest. The rite of adding a new bit of material 

 followed an invariable routine. Eeturning with a tuft of down in 

 her slender bill, she would alight softly on the incipient nest, push 

 in the stuff where it was needed, and then proceed with the shaping 

 of the structure. She bent down her head and, moving around and 

 around, with her long bill shaped the substance to the contour of 

 her body. As she pressed the yielding down more closely to her 

 breast, she erected the bronze-green feathers of her crown, and her 

 folded wings vibrated as if she thrilled in anticipation of the com- 

 pleted nest and the nestlings it was intended to cradle. Then she 

 sat facing in a set direction; and from the way her body bounced 



