278 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1946 
basic pattern of incubation; but this was subject to considerable varia- 
tion from nest to nest, and on different days at the same nest. The 
fundamental pattern was this: the female incubated every night and 
during the middle of the day; the male took a long turn on the eggs 
in both the morning and afternoon. Each sex was responsible for the 
nest twice during the cycle of 24 hours. But their periods of respon- 
sibility might be interrupted by brief absences, during which the eggs 
were left unattended. There is no reason to suppose that the female 
did not sleep continuously in the nest through the night; for the quet- 
zal, like other trogons, appears to be strictly diurnal in its activity. 
The variations in the daily program we shall now consider. 
The male quetzal began his morning session at times ranging from 
5:52 to 7:27 a. m.; but he inclined toward the former hour as the eggs 
neared the point of hatching. If he appeared early, the female might 
continue her long night session until he arrived to replace her. But 
usually she flew out still earlier, from 5:35 to 6:00, and if her mate 
did not appear fairly promptly, she returned in from 5 to 14 minutes 
to await him on the eggs. The male’s period in charge of the eggs 
during the morning was of variable duration; the shortest that I timed 
lasted 2 hours and 13 minutes and was continuous; the longest was for 
4 hours and 30 minutes, broken by one spontaneous absence of 2 
minutes, and another of 21 minutes when he was frightened from the 
nest by a passerby. One male took charge of a nest for 3 hours and 
15 minutes, with three short recesses totaling 38 minutes. 
The female’s midday period began at times varying from 8:21 to 
after 11:10 a.m. Since I usually watched from midday to night- 
fall and from dawn to midday, I timed in full only two periods. One 
began at 9: 35 a.m. and lasted until 1: 14 p. m., 3 hours and 39 minutes, 
broken by a single recess of 7 minutes, from 11:03 to 11:10 a. m. 
The second, at the same nest, began at 8:21 a. m. and continued until 
12:49 p.m., 4 hours and 28 minutes, interrupted only by a brief 
absence of 11 minutes, from 12: 23 to 12:34. 
The male’s afternoon session began at times varying from 12:53 to 
4:36 p.m. Four sessions that I timed lasted 52 minutes, 1 hour and 
9 minutes, 2 hours, and 8 hours and 8 minutes. All were uninter- 
rupted. Hach of the two males is to be credited with one long and one 
short session. 
On a wet, mist-shrouded afternoon soon after her eggs were laid, 
the female at nest 1 resumed charge at 2: 14 p.m. and remained in sole 
charge until the following morning, with brief recesses from 4:18 to 
4:27, and from 5:48 to5:58 p.m. But this was unusual. Asa rule, 
the male sat until about 5:30 p. m., then left the eggs uncovered until 
the female returned for the night, from 5 to 41 minutes later. The 
female at nest 1 arrived consistently earlier than her neighbor at 
