White-headed woodpeckers (Picoides albolarvatus) are important cavity excavators that recently have become the focus of much research because of concerns over population declines. Past studies have focused on nest site selection and survival but information is needed on factors influencing their space use when away from the nest. We examined space use by white-headed woodpeckers during the nesting (MayJul) and post-nesting (Jul-Oct) periods and compared the role of environmental factors (e.g., landcover) and socio-demographic factors (e.g., age, breeding success) in home range size and selection of location. Average size of 99% kernel home ranges was 125 ha (SD AE 59 ha; n ¼ 19) in the nesting period and 137 ha (SD AE 70 ha; n ¼ 30) in the post-nesting period. Minimum convex polygons were generally comparable to or smaller than ranges reported from previous radio-telemetry studies with this species. Although bird weight and age best explained variation in home range size compared to other factors, neither parameter estimate was significant in our models. Thus, even though weight and age were the most-supported factors in our analysis, home range size was largely influenced by factors that we did not measure. We found that most woodpeckers selected home ranges within forest patches that had undergone a recent disturbance; these areas included forests that had recently been burned with prescribed fire by the United States Forest Service (82%) or subject to disease (16%). Most burned patches in our study were small (approx. 4.8 ha) and occurred within otherwise live forest but had nearly complete mortality of adult trees. We suggest that recent forest disturbances, especially mixed-severity prescribed burns, may have been selected by white-headed woodpeckers because they created snags for nesting and future studies should explore this hypothesis. Because home range size was variable and not linked with productivity, it should not be used as an indication of habitat quality without more detailed studies on causal factors that affect space use in this species. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Resumen. Examinamos la asociación entre factores espaciales y temporales con la supervivencia de nidos de individuos de Sialia mexicana que anidan en cavidades de pino ponderosa (Pinus ponderosa) en bosques que se encuentran a lo largo de la ladera este de las montañas Cascade en Washington. Todas las áreas de estudio fueron manejadas para la producción de madera a través de cosechas programadas o por cortes de aprovechamiento después de incendios. Los individuos de S. mexicana tuvieron una puesta promedio de 5.3 ± 0.1 (EE) huevos (n = 131) y los nidos exitosos produjeron en promedio 4.5 ± 0.2 volantones (n = 85). Utilizando una aproximación de selección de modelos, encontramos que la supervivencia de los nidos estuvo en función del tamaño de la puesta y del tratamiento, y que hubo un efecto cuadrático de la edad del nido. Las tasas de supervivencia diaria de los nidos disminuyeron después del inicio de la incubación, luego aumentaron durante el periodo de pichones y fueron mayores para nidos con puestas de más de 5 huevos y en parches de bosque que fueron quemados y reaprovechados. La supervivencia a lo largo de todo el periodo para las puestas (n = 131 nidos) con ≤4, 5 y ≥6 huevos fue de 0.39 (95% IC: 0.11, 0.65), 0.61 (95% IC: 0.34, 0.80) y 0.71 (95% IC: 0.46, 0.85), respectivamente. Las variables de vegetación asociadas a los sitios de anidación no afectaron significativamente la supervivencia de los nidos. La depredación dio cuenta de la mayoría de los fracasos de nidos (34% de los nidos). Sugerimos que la defensa parental puede estar dando cuenta del efecto cuadrático de la edad del nido, ya que los padres defienden el nido más agresivamente a medida que se acerca el momento en que los polluelos abandonarán el nido. Además, que los individuos con puestas mayores son de mayor edad y con más experiencia, lo que resulta en una supervivencia de nidos mayor.Abstract. We examined the association of temporal and spatial factors with nest survival of Western Bluebirds (Sialia mexicana) nesting in tree cavities in ponderosa pine (Pinus ponderosa) forests along the east slope of the Cascade Mountains, Washington. All study areas were managed for timber production through planned harvests or postfire salvage logging. Bluebirds laid a mean clutch of 5.3 ± 0.1 (SE) eggs (n = 131), and successful nests fledged an average of 4.5 ± 0.2 young (n = 85). Using a model-selection framework, we found that nest survival was a function of clutch size and treatment and that there was a quadratic effect of nest age. Daily survival rates decreased after the onset of incubation, then increased through the nestling period, and were higher for clutches with ≥5 eggs and in stands that were burned and salvaged. Survivorship over the entire period for clutches (n = 131 nests) with ≤4, 5, and ≥6 eggs was 0.39 (95% CI: 0.11, 0.65), 0.61 (95% CI: 0.34, 0.80), and 0.71 (95% CI: 0.46, 0.85), respectively. Vegetation variables associated with nest sites did not significantly affect nest survival. Predation accounted for the most nest failures (3...

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