Wildlife Biology/Damage Management

50-09 - Turkey vulture nest selection criteria

Project Leader

Giusti/Keiffer

Affiliation

UC Cooperative Extension Mendocino County

Objective

Long-term quantitative life history studies in different parts of the breeding range are needed to evaluate the factors affecting the status and health of Turkey Vulture populations (Kirk and others 1998). Limited information exists for western populations except in generalized format such as “typically roosts in large trees—e.g., cottonwood (Populus deltoides) – or - on rock outcrops (Davis 1983a, Thomaides and Reid 1984) and on saguaro cactus (Carnegiea gigantea) in southern Arizona (Bennett and Kunzmann 1994).

I am proposing a survey of HREC oak woodlands to identify, catalog, analyze and characterize existing Turkey Vulture (Cathartes aura) roost and nest trees. Data collection will include:1) tree characteristics (species, dbh, height); 2) nest characteristics (cavity volume, entrance dimensions, cavity height, tree structure characteristics); 3) site characteristics (slope, aspect, elevation); and if possible, 4) regurgitated pellet collection. The survey will include a property-wide transects/assessment of existing trees that meet the physical parameters of currently occupied nest trees to better understand the availability of suitable nest sites. The paucity of information regarding tree selection by these large cavity nesters in California’s oak woodlands puts this ubiquitous species at risk of loosing suitable nesting habitat through benign neglect and lack of instructional information for resource managers and planners who have the jurisdiction to protect habitats.

52-08 - Examination of sexual signals in the plumage of the American kestrel (Falco sparverius)

Project Leader

Bowie/Wommac

Affiliation

UC Berkeley Integrative Biology of UC Berkeley

Objective

Many species of raptor exhibit some form of plumage deviation or polymorphism, yet little is understood about why so many species of birds of prey maintain such wide ranging color variation. Explanations for many of the differences in plumage are often confounded by a limited understanding of the application of the color variation in the life history of many groups of birds of prey. This study will examine the possible use of unique plumage characteristics of male American Kestrels (Falco sparverius) as fitness signals used during breeding and nesting. Comparisons will be conducted of plumage patterns of the tail and body coloration of male American Kestrels at nest boxes established on Hopland REC. Data collected from the field will then be joined with studies of plumage characteristics of museum specimens. Examinations of data collected from museum specimens combined and contrasted with information from live birds in the field will provide the ability to unite behavioral data with information of plumage patterning for birds collected from outside of Northern California. The determination of possible fitness signals in the plumage of the American Kestrel will aid in the examination of the evolutionary factors that are behind the maintenance of plumage variation and sexual dichromatism within the genus Falco and other birds of prey.

53-96 - Genetic and morphological stability of small mammals

Project Leader

Kelt

Affiliation

UC Davis Wildlife, Fish, and Conservation Biology

Objective

In 1959, Dr. H. Howard initiated what a very long-term study on voles (Microtus californicus) at HREC. When I joined UCD in late 1995, I began to consider what additional information could be gleaned from these long-enclosed plots. My work is based on the premise that extreme isolation of a species known to exhibit substantial multi-year cycles in population numbers may have led to demographic bottlenecks in these vole populations. Fundamentally, I am investigating loss of genetic variation in isolated vole populations, as well as a specific morphological response to reduced genetic variation. This response - fluctuating asymmetry - may occur when animals are unable to compensate for "environmental abuse" during development. To date my work has documented minimal loss of genetic variation, but we have not completed collecting samples for morphological analyses. HREC pens are highly suitable to this project because of the duration of isolation (46years, or somewhat more than 60 Microtus generations), and the presence of pitfall traps that allow simulated emigration (this prevents populations from expanding exponentially, a dynamic known as the "fence effect").

55-09 - Linking land use change, host diversity, and amphibian malformation

Project Leader

Johnson/Lunde

Affiliation

University of Colorado Ecology and Evolutionary Biology

Objective

Host-parasite interactions are embedded within dynamic, often highly disturbed environments, which can sharply alter patterns of infection and disease risk among hosts. Changes in land use and the resulting shifts in biological communities have been linked to the emergence of pathogens with medical and veterinary importance. However, the ecological mechanisms responsible for increases in infection often remain conjectural. This project examines how the ongoing transformation of landscapes surrounding wetlands influences an emerging issue of conservation importance: amphibian limb deformities. The flatworm parasite Ribeiroia ondatrae, which sequentially infects freshwater snails, larval amphibians, and birds, has been linked to widespread limb deformities in amphibians. Infection and the resulting malformations also increase amphibian mortality, potentially causing declines in amphibian populations. Building upon ecological theory, the current proposal combines broad-scale field surveys and mechanistic experiments to understand how land use change, by altering host density and host diversity, will promote or limit Ribeiroia abundance and amphibian malformations. This effort will specifically seek to identify how biodiversity losses in freshwater ecosystems affect the transmission of pathogenic parasites, such as Ribeiroia. Specific projects at HREC will use experimental mesocosms to explore how changes in community structure affect parasite transmission and pathology. Considering the growing number of emerging infections that threaten human health and wildlife conservation, results of the proposed efforts have broad application potential. Ribeiroia is not only growing in conservation importance itself, but is an excellent analog for other parasite infections of economic and human-health significance (e.g., human blood flukes).