Pest reduction on agricultural lands due to Hawaiian short-eared owls

View the project final report

Commodities

Practices

• Natural Resources/Environment: wildlife
• Pest Management: biological control
• Sustainable Communities: public participation, quality of life

Hawai‘i's increased agricultural biodiversity has attracted an influx of non-native and introduced avian and rodent pests that cause an estimated total of over $100 billion in damage across the United States, with farms statewide reporting up to 80-100% of crop loss due to these pests. Introduced avian and rodent species also act as vectors for disease, dispersal agents for noxious weeds, and competitors with native species. Pest deterrent techniques are costly, impermanent, and often ineffective. Raptors, especially owls, have proven an effective form of biocontrol. Pueo, or the Hawaiian short-eared owl, is the only endemic avian predator on O‘ahu and Maui, with pellet content demonstrating a dietary inclination toward non-native avian, rodent, and invertebrate species. We used a standardized survey protocol to assess: the distribution and abundance of Pueo on O‘ahu and Maui agricultural lands; determine Pueo seasonal habitat use of agricultural lands, through tagging; examine owl pellets to assess potential reduction in crop predation by pest species; and produce a list of possible measures to increase Pueo abundance on agricultural lands, to be applied by farmers and landowners. Pueo occupancy was found to be most influenced by prey biomass distribution and elevation. Diet was found to be consistent with previous studies, and likely is proportional to availability. Further, pueo were found to have much higher site fidelity than continental Short-eared Owls, suggesting that pueo on agricultural lands are occupying the same sites year-round, both providing benefits to farmers year-round, and receiving impacts from potential threats such as secondary poisoning from rodenticide or drowning in water troughs. Through farmer-to-farmer and researcher-to-farmer interactions, we engaged producers, discussed their knowledge of pueo, and shared our results. Producers are now helping to achieve a “win-win-win” for the native Pueo, for Hawai‘i conservation, and for economic benefits to agriculture.

1. Assess the distribution and abundance of Pueo on O‘ahu and Maui, including on agricultural lands.  
2. Evaluate potential reduction in pest species through diet analysis on owl pellets and surveys.  
3. Determine seasonal habitat use by Pueo.  
4. Develop Habitat Conservation Recommendations for Producers.  
5. Increase producer and public awareness of the role of Pueo in agriculture.