Association between Wildlife and Agriculture: Underlying Mechanisms and Implications in Burrowing Owls

Abstract

Western burrowing owls (Athene cunicularia hypugaea) are endangered in Canada and several western U.S. states. Population declines have been linked with control measures aimed at burrowing mammals and loss of nesting habitat. The owls frequently associate with irrigated agriculture throughout portions of their western U.S. range. To determine potential factors driving the association of burrowing owls with agriculture, we examined availability of suitable nest burrows (burrow availability hypothesis), abundance of potential prey (prey availability hypothesis), and predation of nest burrows (predation hypothesis) for owls nesting in the Snake River Birds of Prey National Conservation Area in southwestern Idaho during 2001–2002. Nest burrow availability did not differ between agricultural and nonagricultural habitats, and occupancy rates of owls in artificial burrows were greater near agriculture. More rodent prey species were live‐trapped in agricultural habitat compared with nonagricultural habitat, and there was no difference in relative abundance of prey between habitat types. Pellet remains indicated greater abundance and biomass of prey being consumed in agricultural habitat compared with nonagricultural habitat. Finally, predation rates of dummy nests in agricultural and nonagricultural habitat did not differ. These findings allow us to reject the burrow availability and predation hypotheses, while the prey availability hypothesis remains tenable. Thus, burrowing owls may nest near irrigated agriculture in southwestern Idaho because of increased diversity or availability of prey. We suggest that research is needed to determine how widespread this prey availability relationship may be and how management of burrowing owls in agricultural landscapes may take advantage of this apparent rich prey resource.

CARACTERIZAÇÃO ALIMENTAR DA Athene cunicularia (STRIGIFORMES: STRIGIDAE) (CORUJA BURAQUEIRA)

“…Estudos em que foram comparados diferentes habitat de corujas buraqueiras constataram que, em ambientes agrícolas, estes animais conseguem manter uma maior densidade de ninhos (22,23) , além de ser constatado que a urbanização demonstra um efeito negativo quanto à densidade populacional destas aves (4,20) . Nas duas áreas de estudo foi observado que alguns pontos apresentaram falhas na cobertura vegetal, o que facilitou a fixação das corujas através da construção de tocas.…”

Short-eared Owl (Asio flammeus) surveys in the North American Intermountain West: utilizing citizen scientists to conduct monitoring across a broad geographic scale

“…Fallow agriculture may provide more of the habitat structure preferred by Short-eared Owls than the invasive grasslands in our study area, and the unique plant composition within fallow agriculture may result in increased prey availability (Moulton et al 2006). The association with other agricultural stages may be related to prey availability as well, but could also be the result of recent changes in the landscape after the owls settled in the area, i.e., owls settled when fields were fallow, but stayed when plowed to dirt and green plants began to grow.…”

Burrowing Owl (Athene cunicularia) Habitat Associations in Agriculture Fields and along Canal Trails in Phoenix, Arizona

“…Close proximity to active or historical farmlands may also increase the potential of these parcels as burrowing owl habitat due to increased prey base (Moulton et al 2006). Although Alanen (2004) concluded that burrowing owls were not abundant within the bounds of their survey area, these results might reflect the fact that Avra Valley provides more suitable wintering habitat for burrowing owls.…”