Quantifying the frequency and effects of secondary exposure to rodenticides in barn owls

View the project final report

Commodities

Practices

• Crop Production: application rate management
• Education and Training: farmer to farmer, on-farm/ranch research
• Natural Resources/Environment: wildlife
• Pest Management: biological control, chemical control, integrated pest management
• Production Systems: agroecosystems

Barn owls are a popular component of Integrated Pest Management (IPM) programs for
the control of rodent pests across the Western United States and contribute to
sustainable agriculture through integration of natural biological control, enhancing
the environmental quality of agricultural regions, and sustaining the economic
viability of farm operations. However, because farmers utilize rodenticides to control
rodent pests, owls can suffer from both lethal and sub-lethal secondary poisoning.
Despite the important role that owls can play in providing long-term, sustainable, and
natural pest control services, we have little understanding of how often owls are exposed
to rodenticides and what effect this exposure has on their behavior and reproductive
success.
To tackle this critical gap in knowledge, our study will address five key objectives:
1) Determine if rodenticide exposure affects growth rates in owl nestlings;
2) Understand how land use type, rodenticide applications, and prey choice affect
the frequency of rodenticide exposure;
3) Inform predictive models on the efficacy of barn owls for controlling rodent pests
on farms;
4) Create stakeholder-verified recommendations for the use of rodenticides in
combination with barn owls for effective IPM; and,
5) Disseminate findings to producers through publications, a field-demonstration,
visits to rural schools, and presentations to pest-control and agricultural groups.
We will use innovative blood- and fecal- testing methodologies to detect recent
rodenticide exposure in adult and nestling owls, and will use GPS-tags on adult owls to
understand where they may be capturing poisoned rodents. Our project team is uniquely
positioned to execute the research and education proposed in this application. The
producers on our project team have all utilized barn owls as part of IPM programs for
rodent control on their land and the academics on our project team have contributed to
both research and outreach on vertebrate pest control utilizing raptors.

1) Determine if rodenticide exposure affects growth rates in owl nestlings;
2) Understand how land use type, rodenticide applications, and prey choice affect
the frequency of rodenticide exposure;
3) Inform predictive models on the efficacy of barn owls for controlling rodent pests
on farms;
4) Create stakeholder-verified recommendations for the use of rodenticides in
combination with barn owls for effective IPM; and,
5) Disseminate findings to producers through publications, a field-demonstration,
visits to rural schools, and presentations to pest-control and agricultural groups.