Elena West

Followers

Following

Public Views

Uploads

Papers by Elena West

Garbage in may not equal garbage out: sex mediates effects of ‘junk food’ in a synanthropic species

Journal of Urban Ecology

Human influence on ecosystems is rapidly expanding, and one consequence is the increased availabi... more Human influence on ecosystems is rapidly expanding, and one consequence is the increased availability of human food subsidies to wildlife. Human food subsidies like refuse and food scraps are widely hypothesized to be ‘junk food’ that is nutritionally incomplete; however, the impacts of ‘junk foods’ on the health and fitness of individual organisms remain unclear. In this study, we aimed to understand how human food consumption affects the body condition and fecundity of a generalist predator, the Steller’s jay (Cyanocitta stelleri). We used stable isotope analysis to quantify individual human food consumption (using δ13C as a proxy), estimated individual body condition based on body mass and feather growth bar width and assessed jay fecundity. Adults consumed more human food than juveniles on average, and we observed sex-specific responses to human food use where male body condition tended to increase, whereas female body condition tended to decline with human food consumption. How...

Download

Human food subsidies drive individual specialization and intrapopulation dietary differences in a generalist predator

Ecosphere

Failed despots and the equitable distribution of fitness in a subsidized species

Behavioral Ecology

Territorial species are often predicted to adhere to an ideal despotic distribution and under-mat... more Territorial species are often predicted to adhere to an ideal despotic distribution and under-match local food resources, meaning that individuals in high-quality habitat achieve higher fitness than those in low-quality habitat. However, conditions such as high density, territory compression, and frequent territorial disputes in high-quality habitat are expected to cause habitat quality to decline as population density increases and, instead, promote resource matching. We studied a highly human-subsidized and under-matched population of Steller’s jays (Cyanocitta stelleri) to determine how under-matching is maintained despite high densities, compressed territories, and frequent agonistic behaviors, which should promote resource matching. We examined the distribution of fitness among individuals in high-quality, subsidized habitat, by categorizing jays into dominance classes and characterizing individual consumption of human food, body condition, fecundity, and core area size and spa...

Variation in individual autumn migration and winter paths of Great Lakes red-headed woodpeckers (Melanerpes erythrocephalus)

Animal Migration, 2020

Migratory movements of facultative migrants are poorly understood due to their irregular and ofte... more Migratory movements of facultative migrants are poorly understood due to their irregular and often unpredictable occurrence. However, tracking such movements is important for understanding population dynamics, informing annual cycle conservation plans, and identifying possible cues of facultative migration. We used pinpoint GPS tags to track autumn and winter movements of migratory red-headed woodpeckers (Melanerpes erythrocephalus) to better understand migration frequency, timing, and routes for birds breeding in managed oak savanna systems in the North American Great Lakes region. Proportions of individuals migrating differed between the two sites, with 72% of the Ohio population migrating, while no individuals in the Minnesota population migrated. Of the Ohio birds that migrated, their movements were highly variable in distance and direction but generally occurred south of the breeding site. Wintering sites ranged from 111 – 218 km from the breeding site. Cover types occupied dur...

Download

Serosurvey for West Nile Virus Antibodies in Steller's Jays (Cyanocitta stelleri) Captured in Coastal California, USA

Journal of Wildlife Diseases, 2017

Abstract West Nile virus (WNV) was first detected in New York in 1999 and, during its expansion a... more Abstract West Nile virus (WNV) was first detected in New York in 1999 and, during its expansion across the continental US, southern Canada, and Mexico, members of the Corvidae (ravens, crows, magpies, and jays) were frequently infected and highly susceptible to the virus. As part of a behavioral study of Steller's Jays (Cyanocitta stelleri) conducted from 2011–14 in the coastal California counties of San Mateo and Santa Cruz, 380 Steller's Jays were captured and tested for antibodies to WNV. Using the wild bird immunoglobulin G enzyme linked immunoassay, we failed to detect antibodies to WNV, indicating either that there was no previous exposure to the virus or that exposed birds had died.

Influence of resource subsidies on the foraging ecology of Steller's jays in protected areas

Background/Question/Methods Populations of many native generalist species have increased as a res... more Background/Question/Methods Populations of many native generalist species have increased as a result of anthropogenic landscape change and increases in the availability of anthropogenic food. These synanthropic species threaten less common native species through “spillover predation”, which occurs when synanthropic predators move into relatively unaltered landscapes where they prey on native species. As the expansion of many synanthropic species is closely linked to the prevalence of human-derived foods, understanding how spatial and temporal variation in food subsidies influence behavior and population processes is essential for controlling impacts to threatened species. In California, populations of Steller’s jays (Cyanocitta stelleri) have increased dramatically in protected areas containing remnant populations of the threatened marbled murrelet (Brachyramphus marmoratus), presumably in response to the availability of human foods in recreational areas within these parks. The obje...

More precisely biased: increasing the number of markers is not a silver bullet in genetic bottleneck testing

Molecular Ecology, 2013

In response to our review of the use of genetic bottleneck tests in the conservation literature (... more In response to our review of the use of genetic bottleneck tests in the conservation literature (Peery et al. 2012, Molecular Ecology, 21, 3403–3418), Hoban et al. (2013, Molecular Ecology, in press) conducted population genetic simulations to show that the statistical power of genetic bottleneck tests can be increased substantially by sampling large numbers of microsatellite loci, as they suggest is now possible in the age of genomics. While we agree with Hoban and co‐workers in principle, sampling large numbers of microsatellite loci can dramatically increase the probability of committing type 1 errors (i.e. detecting a bottleneck in a stable population) when the mutation model is incorrectly assumed. Using conservative values for mutation model parameters can reduce the probability of committing type 1 errors, but doing so can result in significant losses in statistical power. Moreover, we believe that practical limitations associated with developing large numbers of high‐quality...

Understanding the Challenges and Rewards of Social-Ecological Research in China

Society & Natural Resources, 2012

Interest in collaborative research on Chinese social and ecological systems has grown dramaticall... more

Download

Reliability of genetic bottleneck tests for detecting recent population declines

Molecular Ecology, 2012

The identification of population bottlenecks is critical in conservation because populations that... more The identification of population bottlenecks is critical in conservation because populations that have experienced significant reductions in abundance are subject to a variety of genetic and demographic processes that can hasten extinction. Genetic bottleneck tests constitute an appealing and popular approach for determining if a population decline has occurred because they only require sampling at a single point in time, yet reflect demographic history over multiple generations. However, a review of the published literature indicates that, as typically applied, microsatellite‐based bottleneck tests often do not detect bottlenecks in vertebrate populations known to have experienced declines. This observation was supported by simulations that revealed that bottleneck tests can have limited statistical power to detect bottlenecks largely as a result of limited sample sizes typically used in published studies. Moreover, commonly assumed values for mutation model parameters do not appea...

Download

Reducing anthropogenic subsidies can curb density of overabundant predators in protected areas

Biological Conservation, 2021

Abstract Protected areas safeguard biodiversity and provide opportunities for human recreation. H... more Abstract Protected areas safeguard biodiversity and provide opportunities for human recreation. However, abundant anthropogenic food subsidies associated with human activities in protected areas can lead to high densities of generalist predators, posing a threat to rare species at broad spatial scales. Reducing anthropogenic subsidies could curb populations of overabundant predators, yet the effectiveness of this strategy is unclear. We characterized changes in the foraging ecology, body condition, and demography of a generalist predator, the Steller's jay, three years after implementation of a multi-faceted management program to reduce anthropogenic subsidies in a protected area in California. Stable isotope analysis revealed that the proportional contribution of anthropogenic foods to jay diets declined from 88% to 47% in response to management. Overlap between jay home ranges decreased after management began, while home range size, body condition, and individual fecundity remained stable. Adult density in subsidized areas decreased markedly from 4.33 (SE: ±0.91) to 0.65 (±0.20) jays/ha after the initiation of management, whereas density in unsubsidized areas that were not expected to be affected by management remained stable (0.70 ± 0.22 pre-management, 0.58 ± 0.38 post-management). Thus, the response of jays to management was density-dependent such that reduced densities facilitated the maintenance of individual body condition and fecundity. Importantly, though, jay population size and collective reproductive output declined substantially. Our study provides evidence that limiting anthropogenic subsidies can successfully reduce generalist predator populations and be part of a strategy to increase compatibility of species protection and human recreation within protected areas.

Elena West

Uploads

Papers by Elena West

Log In