Evolving Bird Management Research at the USDA Wildlife Service’s National Wildlife Research Center

As the methods-development arm of the U.S. Department of Agriculture’s Wildlife Services program, the National Wildlife Research Center (NWRC) is charged with developing tools and information for protecting agriculture, human health and safety, and property from problems caused by wildlife, including birds. Increasingly the NWRC is being asked to provide basic ecological information on the population status of various bird species, and its role is expanding from a reactive one of providing management options to that of predicting long-term implications of various management actions. This paper describes several areas of research by NWRC scientists to address population-level questions in support of WS mission.

EC27-811 Harvesting Wheat in Nebraska with the Combined Harvester Thresher 1926

Frequent inquiry from wheat growers in Nebraska and others as to the relative merits of the combined harvester-thresher as an efficienct and economical harvesting machine led the Nebraska Agricultural College to make a study of this problem in the summer of 1926. The work was carried on by the Departments of Rural Economics and Agricultural Engineering, cooperating with the United States Department of Agriculture which was conducting a similar survey in different parts of the United States. Perkins county, Nebraska, was the area selected for study as it is more or less typical of those parts of the state where combines are used extensively. The purpose of this circular is merely to give such informaition as is available regarding harvesting costs by different methods in Nebraska and not to recommend one method over another since location, acreage, climatic conditions, and topopgraphy all have their influence in determining the most economic method for different communities.

Evaluation of an In Vitro Blood-Based Assay to Detect Production of Interferon-γ By Mycobacterium Bovis–Infected White-Tailed Deer (Odocoileus Virginianus)

Tuberculosis due to Mycobacterium bovis in captive Cervidae was identified as an important disease in the United States in 1990 and prompted the addition of captive Cervidae to the USDA Uniform Methods and Rules for eradication of bovine tuberculosis. As well, M. bovis infection was identified in free-ranging white-tailed deer in northeast Michigan in 1995. Tuberculosis in both captive and free-ranging Cervidae represents a serious challenge to the eradication of M. bovis infection from the United States. Currently, the only approved antemortem tests for tuberculosis in Cervidae are the intradermal tuberculin skin test and the blood tuberculosis test (BTB). At present, the BTB is not available in North America. Tuberculin skin testing of Cervidae is time-consuming and involves repeated animal handling and risk of injury to animals and humans. This study evaluated the potential of a new blood-based assay for tuberculosis in Cervidae that would decrease animal handling, stress, and losses due to injury. In addition, a blood-based assay could provide a more rapid diagnosis. Twenty 6–9-month-old white-tailed deer, male and female, were experimentally inoculated by instillation of 300 colony-forming units of M. bovis in the tonsillar crypts. Seven, age-matched uninfected deer served as controls. Blood was collected on days 90, 126, 158, 180, 210, 238, 263, and 307 after inoculation and was analyzed for the production of interferon-γ (IFN-γ) in response to incubation with M. bovis purified protein derivative (PPDb), M. avium PPDa, pokeweed mitogen (PWM), or media alone. Production of IFN-g in response to PPDb was significantly greater (P < 0.05) at all time points in samples from M. bovis–infected deer as compared with uninfected control deer, whereas IFN-γ production to PWM did not differ significantly between infected and control deer. Measurement of IFN-γ production to PPDb may serve as a useful assay for the antemortem diagnosis of tuberculosis in Cervidae.

Fire Frequency and the Vegetative Mosaic of a Spruce-Fir Forest in Northern Utah

Fire scar and vegetative analysis were used to construct a fire history for the Engelmann spruce/subalpine fir (Picea engelmannii/Abies lasiocarpa) vegetation type of the Utah State University (USU) T. W Daniel Experimental Forest. Three distinct periods of fire frequency were established-presettlement (1700-1855), settlement (1856-1909), and suppression (1910-1990). Mean fire interval (MFI) decreased during the settlement period and greatly increased during the suppression era. The difference was attributed to the influx of ignition sources during the settlement of nearby Cache Valley, located 40 km to the west. Logging and livestock grazing appear to have led to the reduced MFI, which in turn worked as a factor to create the vegetative mosaic now observed on the study area. The increase in MFI during the suppression era permitted the advancement of shade-tolerant species in the understory of the shade-intolerant lodgepole pine (Pinus contorta var. latifolia) and quaking aspen (Populus tremuloides). Continued suppression of disturbance from wildfire will allow the lodgepole pine cover type, which experienced the lowest MFI during the settlement period, to be further invaded by shade-tolerant species, decreasing spatial stand diversity and increasing the risk of more intense fires.

Spatial Relationships Among Young Cercocarpus ledifolius (Curlleaf Mountain Ylahogany)

This study analyzed spatial location patterns of Cercocarpus ledifolius Nutt. (curlleaf mountain mahogany) plants, classified as current-year seedling, established seedling, juvenile, and immature individuals, at a central Nevada study site. Most current-year seedlings were located in mahogany stands in which large, mature individuals had the greatest abundance. These stands had greater litter cover and a thicker layer of litter than areas with few current- year seedlings. Most established young Cercocarpus were located in adjacent Artemisia tridentata ssp. vaseyana (mountain big sagebrush) communities, or in infrequent canopy gaps between relatively few large, mature Cercocarpus. We discuss potential roles of plant litter, root growth characteristics, nurse plants, and herbivory in the establishment and renewal of Cercocarpus communities.

Comparison of Two Roadside Survey Procedures for Dwarf Mistletoes on the Sawtooth National Forest, Idaho

Two roadside surveys were conducted for dwarf mistletoes parasitizing lodgepole pine and Douglas-fir on the Sawtooth National Forest, Idaho. One survey used variable-radius plots located less than 150 m from roads. The 2nd survey used variable-radius plots established at 200-m intervals along 1600-m transects run perpendicular to the same roads. Estimates of the incidence (percentage of trees infected and percentage of plots infested) and severity (average dwarf mistletoe rating) for both lodgepole pine and Douglas-fir dwarf mistletoes were not significantly different for the 2 survey methods. These findings are further evidence that roadside-plot surveys and transect-plot surveys conducted away from roads provide similar estimates of the incidence of dwarf mistletoes for large forested areas.

Western Balsam Bark Beetle, Dryocoetes confusus Swaine, Flight Periodicity in Northern Utah

The flight periodicity of western balsam bark beetle (Dryocoetes confusus Swaine) in Big Cottonwood Canyon, Utah, was studied during the summer months of 1992, 1993, and 1994. Contents of baited funnel traps were tallied by species up to 3 times weekly. Two main periods of flight activity were observed each year. The first and, generally, largest occurred in early summer soon after flight was initiated for the season. A 2nd period was observed in late summer, generally August. Timing of the 2 periods was influenced by unusually warm or cool weather in each study year. The 1st period had more males than females while the 2nd period had a majority of females. Except during periods of cool or wet weather, western balsam bark beetles were found to be active at least at minimal levels from June through September.

Cuticular Hydrocarbons as Chemotaxonomic Characters for Nasutitermes corniger (Motschulsky) and N. ephratae (Holmgren) (Isoptera: Termitidae)

Forty-four cuticular hydrocarbon components from workers of the termites Nasutitermes corniger (Motschulsky) and N. ephratae (Holmgren) from three localities in Panama were characterized by capillary gas chromatography-electron impact mass spectrometry. Both species contain qualitatively identical homologous series of n-alkanes; 2-, 3-, 11-,13-,14-, and 15-methylalkanes; 11,15-, 12,16-, and 13,17-dimethylalkanes; and 11,15,19- and 13, 17,21-trimethylalkanes. Both species also contain a single alkene, 9-hentriacontene. The two species, however, are readily distinguished chemically by differences among the relative abundances of 11 of their major hydrocarbon components.

Reduction of Soil Erosion on Forest Roads

Results of onsite erosion control work from across the United States provide estimates of the amount of erosion reduction on forest roads from various treatments. Supplementary information includes the effects of slope gradient, soil characteristics, and ground cover. Estimates of sediment travel below fillslopes can be made, together with the combined effect of erosion control treatments of the running surface, road cut, and ditch.

SCWDS Briefs: Volume 25, Number 3 (October 2009)

Table of Contents: Clams & AI Virus SCWDS Funded to Study WNS USDA Program Changes Proposed TB in Captive Cervids CWD Prions in Deer Feces TWS Position Statement on Lead WDA Awards For SCWDS Staff New Brochure for Hog Hunters

SCWDS Briefs: Volume 25, Number 1 (April 2009)

Table of Contents: USDA Seeks Comments on New CWD Rule Some of the Intricacies of CWD 3rd International CWD Symposium White Nose Syndrome Update Wildlife Poisoning in Kansas Salmonellosis in Your Backyard Trichomonosis in Songbirds Dr. Al Franzmann Staff & Student Recognition

SCWDS Briefs: Volume 24, Number 4 (January 2009)

Table of Contents: HD in 2007: A Year to Remember Ecology of AIV in Shorebirds New USDA Brucellosis Proposal TWS Seeks Comments on Draft Lead Policy Unusual Eagle Death New SCWDS Grad Students Tennessee Director Retiring 3rd International CWD Symposium Another SCWDS Student Award

Avian Piscivores as Vectors for Myxobolus cerebralis in the Greater Yellowstone Ecosystem

Myxobolus cerebralis, the cause of whirling disease in salmonids, has dispersed to waters in 25 states within the USA, often by an unknown vector. Its incidence in Yellowstone cutthroat trout Oncorhynchus clarkii bouvieri within the highly protected environment of Yellowstone Lake, Yellowstone National Park, is a prime example. Given the local abundances of piscivorous birds, we sought to clarify their potential role in the dissemination of M. cerebralis. Six individuals from each of three bird species (American white pelican Pelecanus erythrorhynchos, double-crested cormorant Phalacrocorax auritus, and great blue heron Ardea herodias) were fed known-infected or uninfected rainbow trout O. mykiss. Fecal material produced during 10-d periods before and after feeding was collected to determine whether M. cerebralis could be detected and, if so, whether it remained viable after passage through the gastrointestinal tract of these birds. For all (100%) of the nine birds fed known-infected fish, fecal samples collected during days 1–4 after feeding tested positive for M. cerebralis by polymerase chain reaction. In addition, tubificid worms Tubifex tubifex that were fed fecal material from known-infected great blue herons produced triactinomyxons in laboratory cultures, confirming the persistent viability of the parasite. No triactinomyxons were produced from T. tubifex fed fecal material from known-infected American white pelicans or double-crested cormorants, indicating a potential loss of parasite viability in these species. Great blue herons have the ability to concentrate and release viable myxospores into shallow-water habitats that are highly suitable for T. tubifex, thereby supporting a positive feedback loop in which the proliferation of M. cerebralis is enhanced. The presence of avian piscivores as an important component of aquatic ecosystems should continue to be supported. However, given the distances traveled by great blue herons between rookeries and foraging areas in just days, any practices that unnaturally attract them may heighten the probability of M. cerebralis dispersal and proliferation within the Greater Yellowstone Ecosystem.

Selective Foraging For Anthropogenic Resources By Black Bears: Minivans In Yosemite National Park

Black bears (Ursus americanus) forage selectively in natural environments. To determine if bears also forage selectively for anthropogenic resources we analyzed data on vehicles broken into by bears from Yosemite National Park, California. We classified vehicles into 9 categories based on their make and model and collected data on use (2001–2007) and availability (2004–2005). From 2001 to 2007 bears broke into 908 vehicles at the following rates: minivan (26.0%), sport–utility vehicle (22.5%), small car (17.1%), sedan (13.7%), truck (11.9%), van (4.2%), sports car (1.7%), coupe (1.7%), and station wagon (1.4%). Only use of minivans (29%) during 2004–2005 was significantly higher than expected (7%). We discuss several competing hypotheses about why bears selected minivans.

Seroprevalence of equine influenza virus in northeast and southern Mexico

EQUINE influenza A virus (EIV) is a highly infectious respiratory pathogen of horses (Hannant and Mumford 1996, Palese and Shaw 2007). The illness is characterized by an abrupt onset of fever, depression, coughing and nasal discharge, and is often complicated by secondary bacterial infections that can lead to pneumonia and death. Two subtypes of EIV, H3N8 and H7N7, have been isolated. The H7N7 subtype was first isolated from a horse in Czechoslovakia in 1956 (Prague/56), and the H3N8 subtype was first isolated from a horse in Miami in 1963 (Sovinova and others 1958, Waddell and others 1963). The last confirmed outbreak of H7N7 occurred in 1979, and this subtype is now considered to be either extinct or circulating at low levels in a few geographical areas (Ismail and others 1990, Webster 1993, Singh 1994, Madic and others 1996, van Maanen and Cullinane 2002). The H3N8 subtype is a common cause of disease in horses worldwide, particularly in areas where vaccination is not routinely performed (Paillot and others 2006).