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

Abstract

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.

First detection of herpesvirus and hemosporidians in the endangered Pyrenean Capercaillie (Tetrao urogallus aquitanicus)

“…In light of the endangered status of the Pyrenean Capercaillie and the expected consequences of climate change for hemosporidian parasite dynamics and mountain bird health, further studies are necessary to clarify the presence of clinical signs and pathologic changes associated with herpesvirus, Haemoproteus and Leucocytozoon . Although sedation methods have been developed to reduce the mortality risk related to capture myopathy and invasive sampling during Pyrenean Capercaillies captures 2 , this species is very sensitive to stress related to handling. Therefore, non-invasive methods and collection of carcasses should be prioritized to study Pyrenean Capercaillie diseases.…”

“…The Pyrenean Capercaillie ( Tetrao urogallus aquitanicus ) is a very elusive endangered subspecies of Western Capercaillie ( T. urogallus , order Galliformes) that sustains local endemism in the Pyrenees and inhabits narrow elevation ranges 1 . This mountain bird is highly sensitive to environmental changes and stress 2 . Several factors are considered threats to Pyrenean Capercaillies, including climate change, habitat fragmentation, increased extensive livestock and wild ungulate populations, and disturbances resulting from off-track practices 2 .…”

“…This mountain bird is highly sensitive to environmental changes and stress 2 . Several factors are considered threats to Pyrenean Capercaillies, including climate change, habitat fragmentation, increased extensive livestock and wild ungulate populations, and disturbances resulting from off-track practices 2 . Additionally, increased temperatures may promote their exposure to novel pathogens that were not originally present and/or that normally belong to other altitudinal ranges 3 .…”