LIFE HISTORY OF THE QUETZAL—SKUTCH 279 
nest 2. Her two evening returns which I witnessed took place at 5:30 
and 5:53. The other female entered at 6:09, 6:01 and 6:07, when 
the daylight was growing faint. 
The noon-to-noon record of the first nest shows that the male in- 
cubated a total of 7 hours; that of the second nest credits him with 
6 hours and 7 minutes, out of approximately 13 hours of total daily 
activity. 
Compared with other, smaller trogons, the quetzal sits for brief 
periods. The fundamental pattern of incubation among trogons is 
the same as for pigeons; there are only two shifts in each 24-hour 
cycle, the male sitting through the middle of the day, the female from 
the middle or late afternoon until the early half of the following 
morning. This is exemplified by my records of the black-headed 
(Trogon m. mellanocephalus), graceful, Jalapa, and Baird’s trogons. 
Because I usually begin or end my observations at midday, I have 
not often watched through the complete session of a male trogon of 
the smaller kinds. But once a male Baird’s trogon sat for exactly 6 
hours, without once showing his head in the doorway of his well-en- 
closed nest; he and his mate kept the eggs continuously covered. So 
did a pair of little graceful trogons in Panama, the noon-to-noon 
record pointing to uninterrupted incubation by the male for about 8 
hours. The male black-headed trogon, sitting in his termitary, takes 
sessions of corresponding length; but he and his mate do not always 
wait for each other before going off to hunt food. 
In contrast to the female quetzal’s impatience to depart from the 
nest in the early morning, I have known a female Mexican trogon to 
extend her night session through the entire morning and until 1:10 
in the afternoon, never once leaving for food. A female Jalapa tro- 
gon sat continuously from 4:51 p. m. until 11:27 next morning, re- 
fusing her mate’s offer to relieve her at the unusually early hour of 
7 a.m. Why the quetzal should incubate so much less assiduously 
than its smaller cousins is not clear. Most trogons nest in lower and 
warmer regions. The Mexican trogons dwelt at a far greater altitude; 
but all were not so patient in incubation as the female to which we 
have referred. With other families, as with the trogons, size has 
little to do with the length of a bird’s sessions on the eggs. 
Upon arriving to replace the mate on the nest, both male and female 
quetzal would often, but by no means always, utter whining or nasal 
notes while perching nearby. At the same time they flash their white 
outer tail feathers with a momentary fanning of the rectrices, then 
twitch the tail upward—a typical trogon gesture. Sometimes the 
partner in the nest would come forth upon hearing the summons, but 
again it might disregard them. Its response doubtless depended upon 
how eager it was to leave. If the bird in the nest did not come forth, 
