The response of nuthatches (Sitta spp.) to restorative treatments in ponderosa pine ecosystems of northeastern Oregon.

Ponderosa pine (Pinus ponderosa,) forests in western North America are in need o f restoration due to the impacts offire suppression. The effects o f different restorative treatments on avian species should be determined before these treatments are widely applied. O f the common resident passerines in ponderosa pine forests, three species are nuthatches fSittaj. These nuthatches have similar ecological niches to each other but different life history traits. The objectives o f this research were to determine differences among treatments in: abundance andforaging behavior o f Pygmy f'Sitta pygmaeaj, White-breasted (S. carolinensisj, and Red-breasted (S. canadensis,) Nuthatches, and daily nest success o f Pygmy and Red-breasted Nuthatches. Structural characteristics o f trees usedfor foraging and nesting were also documented. Thinning ( ‘thin ’ ), prescribed burning ( ‘burn j, thinning followed by burning ( ‘thin and burn j and ‘control’ areas were used. Pygmy Nuthatches were observed more often in ‘thin and burn ’ areas than in ‘thin ’ or ‘burn ’ areas. White breasted Nuthatches were encountered more often in ‘thin and burn ’ units than ‘control ’ units. The abundance o f each species o f nuthatch in treatment areas did not seem to be dictated by tree structural characteristics alone. Red-breasted Nuthatches spent more time foraging on trees in ‘thin and burn ’ areas than in ‘thin ’ or ‘control’ areas, but this difference was not due to tree structure. Red-breasted Nuthatches foraged upon Douglas-fir (Pseudotsuga menziesiij more than it was randomly available, and used trees for foraging that were larger and had less live crown than trees not used. White-breasted Nuthatches foraged on trees that were larger and had less live crown than average. Pygmy Nuthatches were more likely to forage on trees that were large in diameter. Models using structure and microhabitat o f nest trees performed poorly at predicting the success o f nests o f Pygmy and Red-breasted Nuthatches. The number o f nests o f Red-breasted Nuthatches was different among treatments, with fewer nests within ‘thin and bum ’ treatments than expected. The