Modeling Habitat Occupancy of Orange‐Crowned Warblers in Managed Forests of Oregon and Washington, USA

As part of a habitat management planning process for commercially managed forests, we developed and evaluated habitat occupancy models for the orange‐crowned warbler ( Vermivora celata ), a conservation priority species in Oregon and Washington, USA. We used repeated surveys to classify a random sample of managed conifer stands at the McKenzie, PeEll, and Tolt study sites in western Oregon and Washington as either occupied or unoccupied during 1994–1995. We modeled occupancy and detection probabilities as a function of stand‐level habitat characteristics subject to manipulation by management activities. The best‐fitting model indicated that orange‐crowned warblers were 2 times (95% CI: 0.99‐5.1) and 3.8 times (95% CI: 1.5–6.1) as likely to occupy a stand for every 5% increase in evergreen shrub cover and 5‐m decrease in canopy lift (ht to lowest live branch), respectively. Management actions that maintain evergreen shrub cover >10% and permit development of low canopy lifts (4–10 m) should promote habitat occupancy by the orange‐crowned warbler in commercial forests in western Oregon and Washington.