Abstract:During March to June 2016, we studied the incubation behavior and rhythm of Great Coucal (Centropus sinensis) using data-logger in Nonggang, Guangxi Province (22°26′35.20′′﹣22°30′46.90′′N, 106°57′46.35′′﹣107°03′32.99′′E). Through systematic search and tracking the birds′ behavior, we totally found 12 nests. Then, incubation data were obtained by regular observation and automatic temperature recorders from 8 nests. The results showed that: 1) The bird laid one egg every two days while still in the period of nest building. The long and short axis of the eggs were 36.11 ± 0.42 mm and 28.46 ± 0.38 mm respectively, and the egg weight was 16.35 ± 0.51 g (n = 44 eggs). The clutch size were 3﹣5 eggs and the incubation period was 16.75 ± 1.65 d (n = 4 nests). The hatching rate was 45.45% (n = 44 eggs) (Table 1). There was no significant correlation between clutch size and incubation period (Pearson correlation, r = 0.865, P > 0.05); 2) Both adults participated in incubation during the daytime, but only one bird incubated eggs at night. Usually, the one which in charge the job at night stayed at the nest around 19:00 and would last to around 06:00 of the next day (Fig. 2); 3) The length of daily activities was over 700 min (n = 45 d) and the birds took 8.82 ± 0.34 times (n = 45 d) of the recesses per day. Average recess time was 52.91 ± 2.35 min (n = 397 times) which has significant negative correlated to the ambient temperature (r =﹣0.113, P< 0.05) (Table 3, Fig. 4). We suggest the incubation strategy of the birds being lower leaving nest frequency and longer recess time; 4) The average incubation temperature in the nest was 31.7 ± 0.3℃ (n = 4 nests) and increased with nest age (Table 2, Fig. 3). It was positive correlated to the ambient temperature (maximum temperature, r = 0.566; minimum temperature, r = 0.537; mean temperature r =0.706, P <0.01) and the length of activities (r = 0.506, P <0.01); 5) Normally the parents started to incubate right after the clutches were full, however, one nest was delayed incubation by parents for 9 days, during that period, the nest temperature dropped to a minimum of 22.1℃ at night. Under north tropical climate condition in the southwest Guangxi, we suggest high ambient temperature would be an important benifitial factor to the incubating of the Great Coucal.