The clutch size, incubation rhythm of Reeves’s Pheasant (Syrmaticus reevesii) and their responses to ambient temperature and precipitationAbstract: Clutch size and incubation rhythm are critical components of avian life history. Incubating birds must balance the trade-offs between their energy requirements and the thermal needs of the developing embryos. Reeves’s Pheasant (Syrmaticus reevesii ) is a uniparental bird endemic to China that lives in mountain forests, and female Reeves’s Pheasants may adjust their incubation behavior to cope with cold environments and energy stress. Using satellite tracking, we tracked 21 wild female Reeves’s Pheasants in northern Hubei Province, China from 2020 to 2022, and explored the birds’ clutch size, incubation rhythm and their responses to ambient temperature and precipitation. The average clutch size of Reeves’s Pheasant was 7.72 ± 1.51, showing strong seasonal declines, and was markedly affected by the average temperature during the spawning period. During the incubation period, the females took 0.74 ± 0.46 recesses per day with an average recess duration of 99.23 ± 72.93 mins and an average nest attendance of 93.11 ± 5.06%. There was a peak of nest departures at around 13:00, and the recess duration was significantly negatively correlated with both daily mean temperature and daily precipitation. Our findings demonstrated that female Reeves’s Pheasants adjusted their behavior in response to the changing ambient temperature and precipitation, and the unimodal pattern of recess timing may not be driven primarily by the physiological needs of incubating females, but by the thermal needs of their developing embryos.Keywords: clutch size; incubation rhythm; response; ambient temperature and precipitation; Reeves’s Pheasant