The western subspecies of Burrowing Owls (Athene cunicularia hypugaea) have been studied since 1998 on Kirtland Air Force Base, making this the longest running Burrowing Owl monitoring project in New Mexico. We begin surveys for the presence of owls in early March, and we monitor breeding activity throughout the summer. Dispersal surveys are conducted in the fall, and surveys for wintering owls are also conducted. Burrowing Owls are monitored during the breeding season to determine population status, reproductive success, prey availability, and site fidelity.
Declines in Burrowing Owl populations are documented throughout the west, and population trends assessed through this study show similar tendencies. Several proposed mechanisms may be involved in this decline, including high predation rates, habitat loss, the decrease in burrowing mammals, chemical exposure, drought, and migration survival and winter habitat. In our study area, causes of nest failure have been attributed to predation and human disturbance. We use video probes and nest cameras to determine many causes of failure.
In order to examine prey availability, we use pitfall traps to analyze prey abundance and distribution. Traps are installed in three habitats of base annually used by breeding Burrowing Owls. Sampling occurs throughout the breeding season, including during the pair formation, incubation, and nestling/fledgling stages of reproduction.
We band adult and juvenile Burrowing Owls to determine site fidelity and to document dispersal and migration. Since 2003, Envirological Services has trapped and banded 539 Burrowing Owls on Kirtland Air Force Base.
We have been examining the correlations between precipitation and owl productivity and arthropod biomass. Additionally, various relationships between site fidelity and productivity have been evaluated.
We have also conducted Burrowing Owl studies elsewhere in New Mexico, including on Holloman Air Force Base, Fort Bliss Army Base, and Cannon Air Force Base.
Winter habitat condition is one proposed factor contributing to Burrowing Owls’ decline. In order to investigate this idea, we conducted a five year study examining wintering grounds. Radio telemetry and satellite telemetry were utilized to document winter locations of owls that breed in New Mexico. Aerial surveys over New Mexico and Mexico were conducted to locate radio telemetry signals.
We also conducted ground surveys throughout Mexico, southern New Mexico, and south Texas in order to document the presence of wintering owls, identify suitable winter habitat, and find and understand threats to wintering populations. In addition to our surveys, we established a network of collaborators in Mexico to conduct annual surveys for wintering owls. A habitat analysis was conducted using the winter owl location data.