Recreation changes the use of a wild landscape by corvids Author(s): Lauren E. Walker and John M. Marzluff Source: The Condor, 117(2):262-283. Published By: Cooper Ornithological Society https://doi.org/10.1650/CONDOR-14-169.1 URL: http://www.bioone.org/doi/full/10.1650/CONDOR-14-169.1 BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. Your use of this PDF, the BioOne Web site, and all posted and associated content indicates your acceptance of BioOne’s Terms of Use, available at www.bioone.org/page/terms_of_use. Usage of BioOne content is strictly limited to personal, educational, and non-commercial use. Commercial inquiries or rights and permissions requests should be directed to the individual publisher as copyright holder. BioOne sees sustainable scholarly publishing as an inherently collaborative enterprise connecting authors, nonprofit publishers, academic institutions, research libraries, and research funders in the common goal of maximizing access to critical research. Volume 117, 2015, pp. 262–283 DOI: 10.1650/CONDOR-14-169.1 RESEARCH ARTICLE Recreation changes the use of a wild landscape by corvids Lauren E. Walker* and John M. Marzluff College of the Environment, School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA * Corresponding author: [email protected] Submitted October 24, 2014; Accepted February 13, 2015; Published May 6, 2015 ABSTRACT As urban areas have grown in population, use of nearby natural areas for outdoor recreation has also increased, potentially influencing bird distribution in landscapes managed for conservation. Members of the family Corvidae (crows, ravens, jays, and magpies) have strong interactions with humans and may be directly affected by recreation in wild landscapes. In Mount Rainier National Park, we evaluated the effects of vegetation, visitor use, and the availability of human-subsidized food on the use of landscape features by 4 corvid species: Steller’s Jay (Cyanocitta stelleri), Gray Jay (Perisoreus canadensis), Common Raven (Corvus corax), and Clark’s Nutcracker (Nucifraga columbiana). We conducted .1,400 point counts across areas that varied in habitat and in the degree of human recreational impact. We calculated predicted occupancy values while allowing for variation in detection probability. In addition to species- specific suites of vegetation and landscape variables, we found that patterns of human recreation, such as visitor use, food subsidy, and amount of road edge, were also significant in explaining corvid distribution. The number of visitors present during point counts was positively associated with Steller’s Jay and Clark’s Nutcracker use. Common Ravens used areas with fewer people but with a high density of road edge. Gray Jays, Common Ravens, and Clark’s Nutcrackers were each more likely to use sites with anthropogenic food subsidy than sites without subsidies. These changes in landscape use may affect the performance of ecosystem services by corvids and could serve as useful and easily measured bioindicators of the impacts of recreation. Keywords: Clark’s Nutcracker, Common Raven, corvid, Gray Jay, Mount Rainier National Park, PRESENCE, recreation, Steller’s Jay La recreacion´ cambia el uso de los corvidos´ de un paisaje silvestre RESUMEN A medida que la poblacion´ de las a´reas urbanas crece, el uso recreativo de las a´reas naturales vecinas tambien´ crece, influyendo potencialmente la distribucion´ de las aves en los paisajes manejados para la conservacion.´ Los miembros de la Familia Corvidae tienen interacciones intensas con los humanos y pueden ser afectados directamente por las actividades recreativas en los paisajes silvestres. En el Parque Nacional Mount Rainier, evaluamos los efectos de la vegetacion,´ el uso de los visitantes y la disponibilidad de alimentos subsidiados por los humanos sobre el uso de los rasgos del paisaje por parte de 4 especies de corvidos:´ Cyanocitta stelleri, Perisoreus canadensis, Corvus corax y Nucifraga columbiana. Realizamos ma´s de 1,400 conteos por punto en a´reas con distintos ha´bitats y nivel de impacto humano recreativo y calculamos los valores predictivos de ocupacion´ con distintos niveles de probabilidad de deteccion.´ Adema´s de series de vegetacion´ y variables de paisaje espec´ıficos para cada especie, encontramos que los patrones de recreacion´ humana, como el uso de los visitantes, el alimento subsidiado y la cantidad de borde de caminos, tambien´ afectaron significativamente la distribucion´ de los corvidos.´ El numero´ de visitantes presentes durante los conteos por punto estuvo asociado positivamente con el uso por parte de C. stelleri y N. columbiana. C. corax usoa´ ´reas con menos cantidad de gente pero con una alta densidad de bordes de camino. P. canadensis, C. corax y N. columbiana presentaron una mayor probabilidad de uso de sitios con alimentos humanos subsidiados que sitios sin subsidios. Estos cambios en el uso del paisaje pueden afectar el desempeno˜ de los servicios ecosistemicos´ por parte de los corvidos´ y pueden servir como bio-indicadores utiles´ y fa´cilmente medibles de los impactos de la recreacion.´ Palabras clave: corvidos,´ Corvus corax, Cyanocitta stelleri, Nucifraga columbiana, Parque Nacional Mount Rainier, Perisoreus canadensis, PRESENCE, recreacion.´ Q 2015 Cooper Ornithological Society. ISSN 0010-5422, electronic ISSN 1938-5129 Direct all requests to reproduce journal content to the Central Ornithology Publication Office at [email protected] L. E. Walker and J. M. Marzluff Recreation changes landscape use by corvids 263 INTRODUCTION by an increase in nonconsumptive recreation include those that require specialized resources, ground nesters, rare Recreation, ecotourism, and other nonconsumptive hu- species, and those that require large contiguous home man activities affect native wildlife communities and the ranges (Knight and Cole 1995a, Neatherlin and Marzluff ecosystems to which they belong (Edington and Edington 2004, Marzluff and Neatherlin 2006). By contrast, human 1986, Knight and Gutzwiller 1995, Liddle 1997). Human recreation in natural areas may benefit generalist species, recreation in natural areas (e.g., by outdoor photographers, such as corvids (birds of the Family Corvidae, including rock climbers, hikers, and horseback riders) exposes jays, crows, ravens, magpies, and nutcrackers), which are wildlife to direct human disturbance, while the creation able to adapt to living with humans and are associated with of recreational infrastructure (e.g., access roads, bike paths, diverse landscapes. Avian predators, including corvids, may campgrounds, and picnic areas) affects the composition benefit from increased visibility and juxtaposition of diverse and pattern of native landscapes. Although many native resources (e.g., edge habitats; Martin and Joron 2003). species of wildlife are negatively affected by human Corvids are intelligent generalist-omnivores that are well recreation in natural areas (Anderson 1995, Knight and adapted to human presence, often flourishing in urban Cole 1995b, Czech and Krausman 1997), the magnitude areas and in areas of more moderate human presence such and direction of these impacts may vary by species, animal as recreation areas (Marzluff and Angell 2005, Marzluff and condition, season, amount of visitation, type of recreation, Neatherlin 2006, Huhta and Sulkava 2014). In recreation and visitor behavior (Kuss et al. 1990, Liddle 1997, Steidl areas with anthropogenic food, corvids may maintain and Powell 2006). Although localized responses of wildlife, smaller home ranges, and populations may increase in both positive and negative, to recreation are well both number and density (Gutzwiller et al. 2002, Storch documented (Burger and Gochfeld 1998, Gutzwiller et al. and Leidenberger 2003, Marzluff and Neatherlin 2006). 1998, 2002, Marzluff and Neatherlin 2006), population- Changing corvid communities may also affect important level responses over broad spatial scales to patterns of ecosystem functions, including carrion decomposition human recreation have not been evaluated. (Knight and Kawashima 1993, Mason and MacDonald Avian communities may be especially sensitive to 1995), seed dispersal (Vander Wall and Balda 1977, nonconsumptive wildland recreation (Anderson 1995, Tomback and Taylor 1987, Johnson et al. 1997), and nest Knight and Cole 1995b, Miller et al. 1998). The repeated predation (Andren´ 1992, Marzluff and Restani 1999, presence of humans in the environment (e.g., hikers along Ibarzabal and Desrochers 2004). Increasing the spatial a trail) may affect avian richness and abundance (Riffell et perspective on the response of corvids to human al. 1996). Recreation may decrease bird species diversity recreation may increase our understanding of recreation’s and skew density in favor of a few species (Beissinger and effect on ecosystem processes and afford managers the Osborne 1982, Hansen et al. 2005, Devictor et al. 2008) by information they need to achieve a balance between the affecting avian fecundity and survivorship (Miller et al. provision of recreational opportunities and the resulting 2001, Bolduc and Guillemette 2003). Nesting birds in positive and negative influences on the native species, recreational areas may suffer increased nest desertion,