Resumen. Para evaluar los factores que influencian una comunidad suburbana de aves en la costa del norte de California, examinamos la abundancia, riqueza y diversidad de aves invernales en 75 localidades en la ciudad de Arcata. Para cada localidad utilizamos fotografías aéreas para determinar las proporciones de superficie de vegetación y zonas sin vegetación dentro de un radio de 75 m y las distancias a varios elementos del paisaje. La actividad humana fue medida y usada como una covariable en la selección del modelo. La abundancia total de las aves, la riqueza de especies y la diversidad disminuyeron con la proporción de superficie de caminos en un sitio, mientras que la abundancia de especies no nativas aumentó con la cobertura de caminos y estructuras. Las proporciones de cobertura de arbustos y árboles en un sitio predijeron positivamente la abundancia total y la riqueza. El efecto de los árboles sobre la diversidad de especies aumentó positivamente en las áreas más urbanas del pueblo. Varias especies, como Cyanocitta stelleri, Regulus calendula, Chamaea fasciata, Troglodytes troglodytes, Dendroica coronata y Sitta canadensis se asociaron positivamente con la vegetación alta y negativamente con la cobertura de caminos y estructuras. Elanus leucurus se correlacionó positivamente con los pastos y los árboles, y negativamente con la cobertura de caminos y estructuras. Estas especies pueden ser las más vulnerables a los cambios de hábitat asociados con la urbanización en esta área de estudio. Recomendamos mantener/restaurar los arbustos y/o árboles nativos para realzar las comunidades de aves en las áreas desarrolladas o mejorar la planificación donde el desarrollo es inevitable. El incremento de la cobertura de arbustos y árboles puede ser particularmente valioso en los vecindarios nuevos y en las áreas alejadas de los bordes del bosque.Abstract. To evaluate factors influencing a suburban bird community in coastal northern California, we examined the abundance, richness, and diversity of wintering birds at 75 locations within the city of Arcata. for each location we used aerial imagery to determine the proportions of vegetation and impervious surfaces within 75 m and the distances to various landscape features. Human activity was measured and used as a covariate in model selection. Total bird abundance, species richness, and diversity declined with the proportion of road surface at a site, while the abundance of non-native species increased with the cover of roads and structures. The proportions of shrub and tree cover at a site predicted total abundance and richness positively. The effect of trees on species diversity was increasingly positive in more urban areas. Several species, such as Steller's Jay (Cyanocitta stelleri), Ruby-crowned Kinglet (Regulus calendula), Wrentit (Chamaea fasciata), Winter Wren (Troglodytes troglodytes), yellow-rumped Warbler (Dendroica coronata), and Red-breasted Nuthatch (Sitta canadensis), were positively associated with tall vegetation and negatively associated with road and str...

Steller's jays (Cyanocitta stelleri) often store food and return to retrieve the stored items at a later time. Between caching and consumption, stored food has the potential to be pilfered by conspecific observers. We investigated whether individually marked Steller's jays in suburban neighborhoods of Arcata, California, USA, adjusted cache concealment effort when in the presence of conspecifics. Both male and female jays traveled the shortest distances to cache when alone, traveled further when a mate was present, and traveled furthest when neighbors from adjacent territories were present. These results suggest that Steller's jays recognize and respond to social contexts when concealing food items.

Habitat Relationships of Great Gray Owl Prey in Meadows of the Sierra Nevada MountainsRyan KalinowskiThe great gray owl (Strix nebulosa) has been a state endangered species in California since 1980 because of low population size. Annual productivity of the great gray owl in California is thought to be largely dependent on vole (Microtus spp.) and pocket gopher dominance; vole abundance was weakly negatively associated with cattle grazing.Gopher abundance was negatively associated with site wetness, and positively associated with stem density, the frequency of forb presence, cattle grazing, and the dominance of corn lily. When managing meadows for great gray owl conservation, cattle grazing and vegetation should be monitored to accommodate the habitat relationships of both voles and gophers. Management of owl prey may be most efficient by prioritizing wet meadow sites for voles since gophers were not likely to be abundant in wet sites, and vole iv abundance has been correlated with moist soils in other studies. Therefore particularly in areas with moist soils, I recommend maintaining plant sward height commensurate with the habitat relationships of voles found in this study.v ACKNOWLEDGEMENTS

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