Abstract:In this study, the daily vocal pattern of female Common Cuckoos (Cuculus canorus) were described. Recordings were made using 28 passive acoustic recorders during breeding season in Wild Duck Lake Wetland Park, Beijing (10 recorders, from 7th May to 8th July in 2017), Liaohe Delta Nature Reserve, Liaoning (10 recorders, from 28th June to 29th July in 2018), and Dagangzi Forest Farm, Jilin (8 recorders, from 17th May to 10th July). A total of 2 777 female calls (Fig. 1) were detected, with 1 431 calls from Wild Duck Lake Wetland Park, 1 222 calls from Liaohe Delta Nature Reserve, and 124 calls from Dagangzi Forest Farm. The females in Wild Duck Lake Wetland Park and Liaohe Delta Nature Reserve showed a similar pattern of daily vocal activity, reaching a sharp peak in the dawn (Fig. 2a, b); while females in Dagangzi Forest Farm showed two peaks of daily vocal activity, with peak activity occurring around early morning and dusk (Fig. 2c). Through comparing these daily vocal patterns with daily egg-laying pattern (Fig. 2d), we suggest that the function of female call in the study populations is to advertise territory and attract mates, rather than misdirect host defenses. This study helps to understand the function of the female Common Cuckoo call.