Status of burrowing owls in Arizona: Final report

Brown, Nikolle; Mannan, R

INTRODUCTION Burrowing owls are considered to be generally uncommon and local residents in a variety of environments in Arizona (Phillips et al. 1964, Monson and Phillips 1981, Brown 2001a and b). The exception is in the agricultural lands along the Lower Colorado River near Yuma where they are considered to be common (Monson and Phillips 1981, Rosenberg et al. 1991). Relative to other areas within its geographic range, not much is known about burrowing owls in Arizona. Although the status of the species in this state was reviewed in 1979 (Johnson et al. 1979) and in 1986 (Johnson-Duncan et al. 1988), the results were incomplete and the overall status remains unknown. Participants in the Second International Burrowing Owl Symposium in Ogden, Utah, (1998), concluded that the burrowing owl is declining over a majority of its range, and that there is a need for a better understanding of the relationship between burrowing owls and other fossorial animals, such as prairie dogs (Cynomys gunnisoni) and ground squirrels (Citellus sp.). The burrowing owl is already listed as a sensitive species (Endangered, Threatened, Species of Special Concern, or Sensitive) in many states, including California and Utah; and the species is classified as endangered in Canada and threatened in Mexico. At present, although the burrowing owl is on the U.S. Fish and Wildlife Service's (U.S.F.W.S.) list of Species of Management Concern (1995), it has no federal standing in the United States. However, a federal (U.S.F.W.S.) status review of the western burrowing owl has been drafted (Brown 2001a: Arizona). There has been only one localized study conducted on burrowing owls in Arizona (in Tucson; Estabrook and Mannan 1998) and one note published on the species’ diet in Arizona (in an agricultural portion of Mesa; Glover 1953). In 1998, the Arizona Game and Fish Department (AGFD) Partners in Flight Program considered the burrowing owl a Priority Species in the High Elevation Grasslands Habitat classification (Latta et al. 1999). deVos (1998) concluded that there is a need to “conserve and manage Arizona's native grassland habitats” in order to maintain populations of this species. Also more information is needed on the abundance and overall status of burrowing owls in the Arizona, so that a state conservation effort can be initiated, if information warrants such action. In 1998, Brown (2001b) summarized existing information about burrowing owls in Arizona. A database consisting of over 250 locations (general and specific), including the Arizona Breeding Bird Atlas (ABBA) data, was created and an annotated bibliography of burrowing owls in Arizona was initiated. Brown’s (2001b) effort was the first since The Birds of Arizona (Phillips et al. 1964) to compile information about burrowing owls in Arizona. However, deVos (1998) provided a general overview of the species in Arizona. In addition to historical natural habitats, burrowing owls also use areas associated with human development (Phoenix metropolitan area, Tucson; R. Ditch, pers. comm., Estabrook and Mannan 1998) and can cause wildlife/development conflicts if the presence of the owls is not known during planning stages (G. Beatty, AGFD, pers. comm. 1998). With considerable development occurring and slated for Arizona, knowledge of the distribution of burrowing owls could reduce conflicts and provide for mitigation of important habitats and populations of owls. This project was proposed to complete the study initiated by Brown in 1998 (Brown 2001b), and expand on the surveys initiated by Estabrook and Mannan (1998), by gathering more information on the burrowing owl in Arizona. Information on the distribution and abundance of burrowing owls in Arizona should help promote a proactive approach to the conservation and management of a species that is declining over its range.