The full geographic distribution and habitat use of the Florida Burrowing Owl, a state "Species of Special Concern," is not well-understood, particularly in remote, non-urban areas. This thesis aimed to expand and improve knowledge about non-urban burrowing owls. We first compiled databases of historic sighting observations. Fieldwork verified and updated existing breeding observation point records and also yielded new breeding locations. Using a GIS, we characterized observed land use, landcover, relevant soil attributes, projected future land use and managed area status for selected points. We quantified landcover within biologically-determined buffer distances around burrows from our own field-verified records. Using standard resource selection methods, we compared observed and available proportions, calculated selection indices, and determined selection/avoidance for each landcover class. These empirical results were used in combination with expert opinion and literature review to finalize criteria for and map "suitable" landcover. Suitability of relevant soil attributes were also empirically-determined and used to further reduce the overall "suitable" area. The final suitable habitat maps appear to relate well to the overall distribution of known non-urban burrowing owl records and demonstrate that a great deal of potentially-suitable breeding habitat exists throughout Florida's central interior. Improved pasture, the most prevalent landcover class, also appears to be the most strongly selected in this study and may be of high importance to non-urban, breeding burrowing owls. Our results could be useful to wildlife officials managing this species. Recommendations include improving surveys and conservation efforts in non-urban areas and enhancing cooperation with landowners, particularly ranchers, as success on private lands seems critical to the long-term persistence of this species.

We measured ventilation, oxygen consumption and blood gases in burrowing owls (Athene cunicularia) breathing moderate and extreme hypoxic gas mixtures to determine their hypoxic ventilatory threshold (HVT) and to assess if they, like other birds and mammals, exhibit a relationship between HVT and hemoglobin O2 affinity (P50) of their blood. An earlier report of an attenuated ventilatory responsiveness of this species to hypoxia was enigmatic given the low O2 affinity (high P50) of burrowing owl hemoglobin. In the current study, burrowing owls breathing 11% and 9% O2 showed a significantly elevated total ventilation. The arterial partial pressure of oxygen (PaO2) at which ventilation is elevated above normoxic values in burrowing owls was 58 mm Hg. This threshold value conforms well to expectations based on the high P50 of their hemoglobin and the HVT vs. P50 relationship for birds developed in this study. Correcting for phylogenetic relatedness in the multi-species analysis had no effect on the HVT vs. P50 relationship. Also, because burrowing owls in this study did not show a hypometabolic response at any level of hypoxia (even at 9% O2); HVT described in terms of percent change in oxygen convection requirement is identical to that based on ventilation alone.