Are Spotted Owl Populations Sustainable in Fire-Prone Forests?

We examined territory selection, occupancy and reproduction among northern spotted owls (Strix occidentalis caurina) relative to environmental factors influencing wildfire regimes in the eastern Cascade Mountains, Washington, USA. Territory selection was influenced positively by the amount of (a) forest with 30-70% overstory canopy cover; (b) grand fir (Abies grandis) and (c) riparian habitat, and negatively by (a) late-successional forest (LSF); (b) trees 13-19 cm diameter; and (c) elevation. Owl pairs in late-successional reserves (LSRs) were not more productive than those in intervening forests. Owl reproductive rates were lower in territories with more pole-sized trees and with greater annual precipitation at higher, wetter elevations and glaciated landtypes where LSF was abundant. As a result, LSF was not correlated to owl reproduction. The most productive owl pairs occurred in dry forests that were at highest risk to uncharacteristic wildfires. Short-term successional advances toward shade-tolerant, pole-sized trees may have led to abandonment of 45 owl territories in mesic forests. Sustainable conservation in this area should account for physical environmental factors that influence owl population performance and reduce continuity and density of fuels.