Efficacy and risks from a modified sodium nitrite toxic bait for wild pigs

Area of Science:

• Wildlife Management
• Invasive Species Control
• Toxicology

Background:

• Wild pigs (Sus scrofa) are a significant invasive species causing widespread damage globally.
• Early sodium nitrite (SN) bait trials showed excessive bait dropping, posing risks to non-target wildlife.
• Modifications to bait formulation, bait stations, and strategy were developed to mitigate these risks.

Purpose of the Study:

• To evaluate the efficacy of modified SN-toxic bait and baiting strategies in reducing wild pig populations.
• To assess the reduction in dropped bait and associated risks to non-target species.
• To test the modified system across diverse geographical and climatic conditions.

Main Methods:

• Field trials were conducted in Australia and the USA using modified SN-toxic bait and bait stations.
• Bait dropping and wild pig mortality were assessed using systematic transects and remote cameras.
• Non-target species mortality from consuming dropped bait was monitored.

Main Results:

• Modified baiting achieved high wild pig population reductions (76.3% to 90.4%).
• Dropped bait decreased significantly (average 55.5g per site), a 19-fold reduction from previous trials.
• Despite reductions, non-target deaths occurred, including birds and opossums, though no population-level effects were detected.

Conclusions:

• The modified SN-toxic baiting strategy effectively reduced wild pig populations.
• Minimizing hazards to non-target species remains a challenge requiring further investigation.
• Future research will focus on bird deterrents to enhance the safety of this control method.