Population dynamics of Hoopoes Upupa epops and Wrynecks Jynx torquilla in the Valais: Annual report 2021

By the end of the 20th century, the breeding populations of the Eurasian Hoopoe Upupa epops and Eurasian Wryneck Jynx torquilla in Switzerland have strongly declined. To counter this negative trend, around 700 nest boxes have been installed in the Rhone valley between Martigny and Sierre 20 years ago. The populations of these two species breeding in these nest boxes are monitored every year since 2002.

Besides the local conservation goal to ensure a long-term survival of these populations in the Valais we also want to better understand breeding ecology, demography and population dynamics of the two species.

The general survey consists of the control of all nest boxes every second week, the check of occupied nest boxes every fifth day to gather information about the broods, the capture or resighting of adult breeding birds and the ringing of all nestlings. Wrynecks are additionally captured prior to the breeding season by mean of tape luring. Standardized field protocols for each species have been developed and were updated for the last time in spring 2020.

As in the previous year 2020, we ringed all physically handled hoopoes and wrynecks with an alphanumeric colour ring in addition to the standard aluminium ring. The marking with the alphanumeric colour ring allows recognition of the individuals on photographs taken by camera traps at the entrance of the boxes and reduces the need for physical captures.

We continued to collect genetic samples from all physically handled birds (adult and nestlings) from which we did not already have a sample. Genetic samples were obtained by buccal swaps that are taken from the mouth. They allow sex determination and insights into the genetic structure of the population.

Louis Membrez (University Lausanne) conducted his Master thesis on the breeding dispersal in wrynecks. He helped in the field work and analysed the existing demographic data.