Temporal variations in the singing activity and the detection of Turtle Doves Streptopelia turtur: implications for surveys

Daily and seasonal variations in the singing activity of the Turtle Dove and the detectability of territory-holding individuals were examined. The use of registrations of singing birds only was more reliable in identifying territories than registrations of all birds. Approximately 70% of known territories were detected during the two hours after sunrise, with less than 30% detected during the remainder of the day. Census work to determine density should therefore only be undertaken in the early morning. The relatively constant but low detection rate (10-20%) later than five hours after sunrise implies that the collection of data for calculation of indices of abundance can be made at this time.