Hide or die when the winds bring wings: predator avoidance by activity shift in a mountain snake

Area of Science:

• Ecology
• Behavioral Ecology
• Herpetology

Background:

• Predator-prey dynamics are crucial in ecology and conservation.
• Reptile basking increases predation risk, necessitating reduced activity and refuge use, despite costs to thermoregulation and other activities.
• Understanding these trade-offs is key to reptile conservation.

Purpose of the Study:

• Identify predators of Vipera graeca.
• Assess predation pressure through injury analysis (incidence, body length, sex distribution).
• Determine how predation pressure affects viper activity patterns.

Main Methods:

• Observed avian predators at study sites.
• Examined Vipera graeca individuals for injuries.
• Analyzed injury data in relation to viper body length and sex.
• Compared temporal overlap between predator and viper activity.
• Assessed viper activity patterns against thermal conditions.

Main Results:

• Twelve raptor species observed; three directly preyed on Vipera graeca.
• 12.5% of 319 vipers had injuries.
• Injury occurrence increased with viper body length and was higher in females.
• Vipers exhibited temporal shifts in activity, being active earlier/later than thermally optimal.
• Significant temporal overlap existed between potential viper activity and predator presence.

Conclusions:

• Viper activity is constrained by predation risk, not just thermal conditions.
• Predation-related injuries are more frequent in larger, female vipers.
• Vipers adjust activity timing to minimize encounters with avian predators, foregoing optimal thermal periods.