Estimating the population size of a mountain galliform in the context of multi-stakeholder adaptive management.

We designed a participatory monitoring program for the capercaillie population in the French Pyrenees based on lek censuses conducted during the breeding season. This program was implemented by a consortium of stakeholders interested in the conservation of French galliforms. The program, carried out since 2010, relied on a dual frame sampling approach: The first sampled frame was the list of all known leks in the study area. We distinguished two types of known leks: leks known to be active before the onset of the program (with at least one cock detected since 2000) and leks with an indeterminate activity status at the time of the onset of the program. The monitoring program also accounted for the existence of leks that were unknown due mainly to incomplete expert knowledge. We therefore built a complementary area frame by discretizing the study area into a set of 4-km2 grid cells. These cells were then sampled and searched to find unknown leks. When unknown leks were found, cock censuses were organized. An additional field experiment allowed us to estimate the detection probability of unknown leks during these cell searches. We then fitted two hierarchical models: (i) An N-mixture model fitted to the lek census data set allowed us to estimate the mean number of cocks on the three types of leks (known active, known indeterminate, and unknown leks); and (ii) another model fitted to the cell search data set allowed us to estimate the number of unknown leks in the studied mountain range. By multiplying the estimated mean numbers of cocks associated with the three types of leks by the number of leks of each type (an estimated value in the case of unknown leks), we obtained estimates of the total numbers of cocks on all leks at different spatial scales in the study area every 2 years. Our model suggests that the capercaillie cock population was stable from 2010 to 2017 over the whole range but decreased slightly in the foothill area and western part, a decrease that worsened in 2018-2019.

Sedation of Wild Pyrenean Capercaillie (Tetrao urogallus aquitanicus) Using Intramuscular Midazolam.

Global Positioning System (GPS) tracking offers key information in the study of movement ecology of threatened species. Nevertheless, the placement of GPS devices requires animal capture and handling, which may represent a challenge to the individual's survival after release, mainly due to capture myopathy. The Pyrenean Capercaillie (Tetrao urogallus aquitanicus) is a threatened galliform especially sensitive to handling, extremely elusive, and challenging to capture. Our goal was to adapt a sedation protocol for Pyrenean Capercaillies undergoing GPS tagging, in order to increase their welfare and safety during the procedure. From 2018 to 2021, 23 wild Pyrenean Capercaillies were captured and sedated for GPS tagging as part of a European conservation project of emblematic Pyrenean avian species. The birds received intramuscular (IM) sedation with midazolam (ranging from 1.9 mg/kg to 8.08 mg/kg) and were handled for 20 to 40 min. Sedation was reversed with flumazenil (0.1 mg/mL IM). The sedated capercaillies were less responsive to stimuli (i.e., closed eyes and recumbency), showing discrete to no response to handling (i.e., placement of the GPS device, physical examination, cloacal temperature measurement, or reflex tests). Such response was compared in birds with sedation doses above and below the average dose (5.17 mg/kg). Only one clinical sign showed statistically significant differences between the two groups ("open-mouth breathing" sign, p = 0.02). A mortality rate of 4.35% was registered (one individual died during handling). Sedation facilitated the handling of the birds and faster interventions in the field, without increasing mortality when compared to handling without sedation. Therefore, sedation was shown to be a useful tool to reduce stress related to capture and handling of the threatened Pyrenean Capercaillie.