Keystone predators can impact many prey species, including those that are endangered. In order to assess the impact predators have on different prey populations, it is essential to identify the species being consumed in different types of aquatic comm . . .

Scent-marking, the deposition of a scent-containing excretion as a means of intraspecific olfactory communication, is common among mammals. For the North American river otter (Lontra canadensis) the latrine serves as a primary area for scent-marking w . . .

This project was designed to assess if the California Native Plant Society Vegetation Monitoring Program (CNPS VMP) provides habitat data useful for predicting bird distributions. In 2004-2005, point counts for bird occurrences and relevé vegetation s . . .

Ecosystem services, such as pest control and pollination, are critical benefits of biodiversity necessary for agricultural production. Predators, including insectivorous birds and ants, can provide important biological controls in agroecosystems, boos . . .

I evaluated nesting habitat relationships of northern spotted owls (Strix occidentalis caurina) on private lands in coastal northwestern California by comparing habitat metrics (nesting, roosting, foraging, and shrub habitats, amount of core area and . . .

Anthropogenic activities in the coastal plain of the Smith River have reduced the quality and quantity of productive salmonid rearing habitat. Consequently, restoration is needed to aid in the recovery of the threatened Smith River coho salmon (Oncorh . . .

Conserving threatened and endangered species requires knowledge of species breeding productivity and the factors that cause variation in reproductive success. I summarized 13 years of reproductive data to quantify lifetime reproductive success (LRS) f . . .

Arctic geese arriving at spring stopover areas are under strict time constraints to build-up endogenous fat and nutrient stores before migrating to their northern breeding grounds. Gizzard grit facilitates the mechanical breakdown of ingested food pla . . .

The Western Snowy Plover (Charadrius alexandrinus nivosus) is a federally listed threatened species as well as a state listed “species of special concern” in California. Accurate survival estimates are required to determine the best conservation strat . . .

Recently, the United States Department of Agriculture’s Natural Resource Conservation Service and Farm Service Agency have been required by the Office of Management and Budget to quantify the effects of the conservation programs they administer. For e . . .

Snowy Plovers (Charadrius nivosus) have been characterized as nesting semicolonially, which means nests are clustered (but to a lesser degree than for colonial species), so that suitable habitat nearby is unoccupied. I assessed the spatial pattern of . . .

I quantified landscape variables surrounding 31 white-tailed kite (Elanus leucurus) nest sites and compared them with 31 unused sites in an undeveloped landscape in southwestern California. Using a geographic information system, I combined landcover d . . .

Lyme borreliosis is recognized as the most common emerging tick-borne disease affecting humans in the United States. In northwestern California, the ecology of Lyme borreliosis is complex, with several potential reservoirs, multiple tick vectors, and . . .

Exposure to Anaplasma phagocytophilum and ticks in gray foxes (Urocyon cinereoargenteus) in northern Humboldt County, California. Granulocytic anaplasmosis is an emerging zoonotic tick-borne disease with over 1300 human cases documented in the US sinc . . .

I compared prey use and reproduction of common murres (Uria aalge) at two spatially disjunct colonies during 2006 and 2007 to examine if prey use of murres differed between locations and investigate how foraging ecology affects murre productivity. Pre . . .

I examined the relationship between nonbreeding dunlin (Calidris alpina) roost use on Arcata Bay and energy balance (proximity hypothesis), predation, and predation risk. Individuals used roosts that were closer to their last foraging locations than r . . .

Land conversion for agriculture is a leading threat to bird biodiversity. However, wildlife-friendly practices such as organic farming and the use of hedgerows have been found to provide needed habitat for birds in agricultural landscapes. Many studie . . .

I investigated the spatial distribution of spring staging black brant Branta bernicla nigricans on South Humboldt Bay, California, to determine how brant selected intertidal feeding sites. From January through May 2000, I mapped the locations of brant . . .

Pollinators are critical for the proper functioning of natural ecosystems and they benefit or are required by many agricultural crops. Despite their importance, there is little information available to enhance restoration efforts or manage habitats to . . .

Since extirpation from almost the entirety of the United States in the early 20th century, gray wolves have begun to reestablish populations across their historic range. After reintroduction of wolves into the greater Yellowstone area in 1995, wolves . . .

Little is known about the space use of breeding Common Ravens (Corvus corax) in Redwood National and State Parks (RNSP) despite their identification as nest predators of the Marbled Murrelet (Brachyramphus marmoratus). We used radio telemetry to exami . . .

Nest predation is often a limiting factor in the recovery of threatened and endangered bird species, especially in ground-nesting birds. A variety of predator management techniques are used to reduce the impact of predation on listed species. I examin . . .

I studied roosting dunlin (Calidris alpina pacifica) in winter at ten sites around Humboldt Bay, California to determine roost site preferences, if any, in relation to the numbers and types of predators and human activity nearby. Based on roost locati . . .

I examined foraging habitat use, foraging site selection and diet of Cooper’s Hawks within the Goosenest Adaptive Management Area in northern California, where experimental interior Ponderosa pine forest restoration treatments have been applied. Two d . . .

Spotted Owls (Strix occidentalis) appear heat intolerant. One of the hypotheses to explain the close association of Spotted Owls with old-growth coniferous forests is that the multilayered and complex structure of these forests provides a cooler micro . . .

The Humboldt marten (Martes caurina humboldtensis) is a habitat specialist that requires large, old woody structures such as live trees, snags, and logs to provide suitable resting and denning locations. Many timber harvesting practices remove these w . . .

I evaluated the hypothesis that fruit availability significantly influences stopover habitat quality for fall migrating Swainson’s Thrushes (Catharus ustulatus) in coastal northern California. I analyzed plasma metabolites (triglycerides, β-hydroxy-bu . . .

Timber harvesting can be highly detrimental to terrestrial amphibians and their habitats. Clearcutting reduces relative abundance of amphibians, however, little is known about the effects of partial-harvesting methods and silvicultural edges on amphib . . .

Agricultural expansion to meet rising demands for crops is one of the greatest threats to terrestrial biodiversity. Coffee, one of the most valuable trade items in tropical countries, provides economic livelihood and habitat for wildlife, especially w . . .

Anthropogenic disturbance may alter the movements and habitat use of Roosevelt elk (Cervus elaphus roosevelti). Persistent human disturbance may ultimately lead to increased energetic demands, decreased reproductive success, a greater risk of predatio . . .

Wintering geese and sandhill cranes (Gros canadensis) prefer feeding in short sparse vegetation, whereas breeding dabbling ducks prefer nesting in tall dense vegetation. I examined whether these two contrasting objectives could be met in uplands manag . . .

Translocation has been used to augment declining Greater Sage Grouse (Centrocercus urophasianus, hereafter sage grouse) populations for several decades. However, little or no data are available directly comparing translocated and resident sage grouse . . .

Substantial increases in mountain lion-human conflicts in the western United States have created a need for quantitative assessment of lion (Puma concolor) resource selection at multiple scales. Using a fixed kernel estimator, multi-year seasonal home . . .

For endangered metapopulations, the roles of source-sink dynamics are easily overlooked or not fully understood when formulating delisting requirements. This could lead to unrealistic recovery criteria imposed on sink populations, which in turn might . . .

Interaction between species through competition is one of the principle processes shaping the structure of ecological communities. Competition can have significant effects on the behavior, distribution, and ultimately the population dynamics of specie . . .

Understanding intraspecific spatial patterns and interactions of American black bears (Ursus americanus) can improve the understanding of social behavior and management of the species. Few studies have examined spatial patterns of American black bears . . .

Pressure from potential predators makes vigilance critical for an individual’s survival, especially during times of vulnerability. California condors (Gymnogyps californianus), with their heavy bodies and large, broad wings, are slow to take-off. This . . .

Frogs in the family Ranidae are considered generalist predators that consume prey as it is encountered in the environment. However, few studies have attempted to quantify the types and relative amounts of prey available to these frogs so a thorough un . . .

Montane meadows represent one of the most critical habitats in the Sierra Nevada Mountains for breeding birds. Livestock grazing in and around montane meadows can produce deleterious ecological effects including changes in the structure and complexity . . .

Many birds replenish energy reserves during semiannual migratory stopover periods in northeastern Costa Rica. Despite the importance of tropical staging areas to migrants, little research has focused on tropical stopover ecology. In this study, habita . . .

Habitat loss and degradation by invasive species is a primary limitation to the recovery of the Western Snowy Plover (Charadrius nivosus nivosus), a federally threatened shorebird that resides on coastal beaches in Humboldt County, California. This ha . . .

Barred owls recently expanded their range and now completely overlap that of the northern spotted owl. Current declines in northern spotted owl populations are largely attributable to this sympatry with barred owls. Lethal removal of barred owls is be . . .

Roosting habitat is one of the most essential habitat components to consider for conservation of bat populations. Basal hollows found almost exclusively in old growth redwood trees provide a distinct roost type that has been recognized as a widely use . . .

Animals capable of innovation are able to solve novel problems or create novel solutions to existing problems. Performance in problem-solving tasks may be influenced by an individual’s characteristics and its social environment. I examined how individ . . .

High abundance and survival of eelgrass (Zostera marina), a foraging resource in Humboldt Bay, California, is imperative to the success of the black brant goose (Branta bernicula nigricans) population. The grazing optimization model predicts an increa . . .

Predation is difficult to observe and quantification of impacts have consequently been difficult, especially for predators active at night. Using night-capable cameras placed throughout a California least tern (Sternula antillarum browni) colony I exa . . .

The Common Raven (Corvus corax) poses a conservation dilemma because as a native predator it can negatively affect populations of other native species, including the Western Snowy Plover (Charadrius nivosus nivosus). In Humboldt County, the Common Rav . . .

In Western Snowy Plovers (Charadrius alexandrinus nivosus), both parents share incubation duties, with males typically incubating at night and females incubating during the day. Typically, plovers run off the nest at a long distance from potential nes . . .

Diseases are potential threats to wildlife populations worldwide, and recent epidemics have demonstrated their far-reaching impacts. The spread of directly transmitted pathogens is influenced by host contact rates, and host density can alter these con . . .

I measured the reproductive response of Modesto Song Sparrow (Melospiza melodia mailliardi) to the experimental removal of an introduced predator, the black rat (Rattus rattus), and identified nest predators using video cameras at the Cosumnes River P . . .