Animal Sciences Commons^™

A Decision Tool To Identify Population Management Strategies For Common Ravens And Other Avian Predators, Andrea F. Currylow, Brenda J. Hanley, Kerry L. Holcomb, Timothy Shields, Stephen Boland, William I. Boarman, Mercy Vaughn

Human–Wildlife Interactions

Some avian species have developed the capacity to leverage resource subsidies associated with human manipulated landscapes to increase population densities in habitats with naturally low carrying capacities. Elevated corvid densities and new territory establishment have led to an unsustainable increase in depredation pressure on sympatric native wildlife prey populations as well as in crop damage. Yet, subsidized predator removal programs aimed at reducing densities are likely most effective longer-term when conducted in tandem with subsidy control, habitat management, and robust assessment monitoring programs. We developed decision support software that leverages stage structured Lefkovitch population matrices to compare and identify treatment …

Synthesis Of Nest Predation Impacts Of Common Ravens On Sensitive Avian Species, Peter S. Coates, William C. Webb, Seth J. Dettenmaier, Seth M. Harju, David J. Delehanty

Human–Wildlife Interactions

Decades of mounting scientific evidence have revealed that common raven (Corvus corax; raven) population numbers have been increasing across nearly all regions of their geographic range in North America. Concomitantly, numerous native wildlife species have experienced elevated predation rates from ravens as populations have increased and expanded their range. Managers are concerned that increased raven predation of many threatened and endangered avian species in the U.S. and Canada during nesting periods may be hampering species recovery. We explored the literature to aggregate existing knowledge and evaluate the impacts of raven predation on nests and young of sensitive avian …

Evaluating Common Raven Take For Greater Sage-Grouse In Oregon’S Baker County Priority Conservation Area And Great Basin Region, Frank F. Rivera-Milán, Peter S. Coates, Jacqueline B. Cupples, Michael Green, Patrick K. Devers

Human–Wildlife Interactions

The common raven (Corvus corax; raven) is a nest predator of species of conservation concern, such as the greater sage-grouse (Centrocercus urophasianus). Reducing raven abundance by take requires authorization under the Migratory Bird Treaty Act. To support U.S. Fish and Wildlife Service’s take decisions (e.g., those that authorize killing a specified proportion or number of individuals annually in a defined area), including the most recent one for Oregon’s Baker County Priority Area for Conservation (PAC), we modeled raven population dynamics under hypothetical scenarios with take rates ranging from below to above the maximum sustained yield (MSY; …

Increased Abundance Of The Common Raven Within The Ranges Of Greater And Gunnison Sage-Grouse: Influence Of Anthropogenic Subsidies And Fire, Jonathan B. Dinkins, Lindsey R. Perry, Jeffrey L. Beck, Jimmy D. Taylor

Human–Wildlife Interactions

The common raven (Corvus corax; raven) is native to North America and has increased in abundance, especially throughout western North America, during the last century. Human subsidies have facilitated raven dispersal into less suitable habitats and enabled these populations to maintain higher annual survival and reproduction. Concomitantly, overabundant raven populations are impacting other native at-risk species such as the greater sage-grouse (Centrocercus urophasianus) and potentially the Gunnison sage-grouse (C. minimus). Using Breeding Bird Survey data from 1995–2014, we evaluated raven count data to quantitatively describe changes in abundance and expansion into sagebrush (Artemisia …

Thinking Like A Raven: Restoring Integrity, Stability, And Beauty To Western Ecosystems, John M. Marzluff, Matthias-Claudio Loretto, Cameron K. Ho, Georgia W. Coleman, Marco Restani

Human–Wildlife Interactions

Common ravens (Corvus corax; ravens) are generalist predators that pose a threat to several rare wildlife species in the western United States. Recent increases in raven populations, which are fueled by increased human subsidies—notably food, water, and nest sites—are concerning to those seeking to conserve rare species. Due to the challenges and inefficiencies of reducing or eliminating subsidies, managers increasingly rely on lethal removal of ravens. Over 125,000 ravens were killed by the U.S. Government from 1996 to 2019, and annual removals have increased 4-fold from the 1990s to mid-2010s. We contend that lethal removal of ravens, while capable …

Assessing Habitat Suitability Of Ribbed Mussels (Geukensia Demissa) In Georgia Salt Marshes By Examining Predicted Mussel Densities And Mussel Population Parameters, William K. Annis Jr

College of Graduate Studies: Theses & Dissertations

Geukensia demissa (ribbed mussel) is an ecology important bivalve that has the potential to contribute to salt marsh restoration. Understanding the factors that contribute to the distribution of mussels can help inform managers on choosing locations to optimize the survivorship of mussels in restoration projects. This study sought to model mussel densities across the coast of Georgia and to compare predicted mussel densities with mussel population parameters as means to gauge habitat suitability. Mussel densities were collected through field surveys across a range of salt marshes along the coast of Georgia and were compared with spatial data such as distance …

Age, Growth, And Mortality Of Atlantic Tripletail In The North-Central Gulf Of Mexico, Amanda E. Jefferson, Matthew B. Jargowsky, Meagan N. Schrandt, Pearce T. Cooper, Sean P. Powers, John Dindo, J. Marcus Drymon

University Faculty and Staff Publications

In the southeastern USA and the Gulf of Mexico (GOM), Atlantic Tripletail Lobotes surinamensis are increasingly targeted by recreational anglers, indicating that stock status should be assessed. A critical need for such assessments is age-specific data; however, previous studies have drawn conflicting conclusions regarding the most appropriate structure for aging. Moreover, growth parameters and mortality rates for GOM Atlantic Tripletail are unknown. Therefore, the goals of this study were to (1) evaluate sagittal otoliths and first dorsal spines as aging structures; (2) model combined and sex-specific growth; and (3) estimate mortality rates for GOM Atlantic Tripletail. From 2012 to 2019, …

Documentation Of Atlantic Tarpon (Megalops Atlanticus) Space Use And Move Persistence In The Northern Gulf Of Mexico Facilitated By Angler Advocates, J. Marcus Drymon, Matthew B. Jargowsky, Michael A. Dance, Mitchell Lovell, Crystal L. Hightower, Amanda E. Jefferson, Andrea M. Kroetz, Sean P. Powers

University Faculty and Staff Publications

Atlantic tarpon (Megalops atlanticus, hereafter tarpon) are facing a multitude of stressors and are considered Vulnerable by the IUCN; however, significant gaps remain in our understanding of tarpon space use and movement. From 2018 to 2019, citizen scientists facilitated tagging of 23 tarpon with SPOT tags to examine space use and movement across the northern Gulf of Mexico. Movement-based kernel densities were used to estimate simplified biased random bridge-based utilization distributions and a joint move persistence model was used to estimate a behavioral index for each fish. Tarpon showed consistent east–west movement from the Alabama/Florida border to Louisiana, and utilization …

Diets Of Double-Crested Cormorants In The Lake Winnebago System, Wisconsin, Ryan P. Koenigs, Daniel J. Dembkowski, Charles D. Lovell, Daniel A. Isermann, Adam D. Nickel

United States Department of Agriculture Wildlife Services: Staff Publications

Double-crested cormorant Phalacrocorox auritus Lesson (cormorant) populations have increased throughout the Great Lakes region of North America causing concern related to the impact of cormorant predation on fish communities. A recent decline in yellow perch Perca flavescens (Mitchill) abundance within the Lake Winnebago System, Wisconsin, USA, prompted an assessment of cormorant diets to evaluate potential effects of cormorant predation on the sportfish community. Diets were collected from 883 cormorants (417 from Lake Winnebago and 466 from Lake Butte des Morts) between 2015 and 2017. Cormorant diets on both waterbodies consisted mostly of freshwater drum Aplodinotus grunniens Rafinesque and gizzard shad …

Jaguars And Pumas Exhibit Distinct Spatiotemporal Responses To Human Disturbances In Colombia’S Most Imperiled Ecoregion, Joe J. Figel, Sebastián Botero-Cañola, Juan David Sánchez-Londoño, Javier Racero-Casarrubia

University of Nebraska State Museum: Mammalogy Papers

Abstract

Coexistence of sympatric felids is facilitated by mutual avoidance and the partitioning of habitats, prey, and time. Anthropogenic disturbances disrupt this coexistence in fragmented landscapes, potentially triggering cascading influences in ecological communities. We used photographic data from 8,717 trap nights (November 2014–June 2016) at 87 camera trap sites in Colombia’s middle Magdalena River basin to compare spatiotemporal overlap among jaguars (Panthera onca), pumas (Puma concolor), their prey, and humans, at sites of high and low disturbance, as determined by the human influence index. Human disturbance events (e.g. domestic dogs, livestock, and humans, including armed hunters) …

Evidence On The Effectiveness Of Small Unmanned Aircraft Systems (Suas) As A Survey Tool For North American Terrestrial, Vertebrate Animals: A Systematic Map Protocol, Jared A. Elmore, Michael F. Curran, Kristine O. Evans, Sathishkumar Samiappan, Meilun Zhou, Morgan B. Pfeiffer, Bradley F. Blackwell, Raymond B. Iglay

United States Department of Agriculture Wildlife Services: Staff Publications

Background: Small unmanned aircraft systems (sUAS) are replacing or supplementing manned aircraft and groundbased surveys in many animal monitoring situations due to better coverage at finer spatial and temporal resolutions, access, cost, bias, impacts, safety, efficiency, and logistical benefits. Various sUAS models and sensors are available with varying features and usefulness depending on survey goals. However, justification for selection of sUAS and sensors are not typically offered in published literature and existing reviews do not adequately cover past and current sUAS applications for animal monitoring nor their associated sUAS model and sensor technologies, taxonomic and geographic scope, flight conditions and …

Recolonizing Carnivores: Is Cougar Predation Behaviorally Mediated By Bears?, Kristin N. Engebretsen, Jon P. Beckmann, Carl W. Lackey, Alyson M. Andreasen, Cody Schroeder, Pat Jackson, Julie K. Young

United States Department of Agriculture Wildlife Services: Staff Publications

Conservation and management efforts have resulted in population increases and range expansions for some apex predators, potentially changing trophic cascades and foraging behavior. Changes in sympatric carnivore and dominant scavenger populations provide opportunities to assess how carnivores affect one another. Cougars (Puma concolor) were the apex predator in the Great Basin of Nevada, USA, for over 80 years. Black bears (Ursus americanus) have recently recolonized the area and are known to heavily scavenge on cougar kills. To evaluate the impacts of sympatric, recolonizing bears on cougar foraging behavior in the Great Basin, we investigated kill sites of 31 cougars between …

Common Raven Nesting And Spatial Distancing On Power Lines In Southeast Idaho, Usa, Quinn R. Shurtliff, Jericho C. Whiting

Human–Wildlife Interactions

Common raven (Corvus corax; raven) abundance and distribution have increased in western North America in recent decades, facilitated by anthropogenic subsidies and other environmental changes. Electrical power transmission line structures provide nesting substrates for ravens. When these structures transect landscapes where natural nest substrates are limited, they may facilitate raven predation on eggs and juveniles of sensitive avian and reptile species. Little information is available regarding raven nest density trends on adjacent power lines or how raven territorial behavior influences spatial partitioning of nests, and hence, nest density. This knowledge would be valuable for managers of sensitive prey …

A Rapid Assessment Function To Estimate Common Raven Population Densities: Implications For Targeted Management, Brianne E. Brussee, Peter S. Coates, Shawn T. O'Neil, Seth J. Dettenmaier, Pat J. Jackson, Kristy B. Howe, David Delehanty

Human–Wildlife Interactions

Common raven (Corvus corax; raven) populations have increased over the past 5 decades within the western United States. Raven population increases have been largely attributed to growing resource subsidies from expansion of human enterprise. Concomitantly, managers are becoming increasingly concerned about elevated adverse effects on multiple sensitive prey species, damage to livestock and agriculture, and human safety. Managers could benefit from a rapid but reliable method to estimate raven densities across spatiotemporal scales to monitor raven populations more efficiently and inform targeted and adaptive management frameworks. However, obtaining estimates of raven density is data- and resource-intensive, which renders …

A Novel Technique To Improve Capture Success Of Common Ravens, Lindsey R. Perry, Terrah M. Owens, Zachary T. Slick, Jimmy D. Taylor, Jonathan B. Dinkins

Human–Wildlife Interactions

Traditional trapping techniques for common ravens (Corvus corax; raven) require significant effort, often produce low capture rates, and cannot be used in some situations. We designed a 3-m noose pole to secure ravens from nocturnal roost locations while using a strobe spotlight to temporarily disorient them. We collected measures of trapping efficiency and contrasted them with padded leghold traps also used in the study. We effectively implemented our noose pole method in July and August of 2018, 2019, and 2020 in the Baker and Cow Lakes sage-grouse (Centrocercus urophasianus) Priority Areas of Conservation in eastern Oregon, …

A Reintroduction Retrospective: Comparative Fisher (Pekania Pennanti) Survival And Prey Habitat Use In The Cascade Mountains Of Washington State, Tanner S.T. Humphries

Graduate Student Theses, Dissertations, & Professional Papers

Increasing human impacts on biodiversity highlight the global need for ecological restoration. For many wildlife species, reintroduction is necessary to re-establish populations in parts of their historic range where they have been extirpated. Reintroduction efforts are commonly used to help restore ecosystem integrity, but are often expensive, time consuming, and unsuccessful at generating self-sustaining populations. Thus, a more complete understanding of the factors affecting restoration success is important for ensuring successful outcomes and responsible stewardship. Fishers (Pekania pennanti) are one of the most commonly reintroduced carnivores in North America, but the success of such efforts is highly variable, …

Spatial Transferability Of Expert Opinion Models For American Beaver Habitat, Isidro Barela, Leslie M. Burger, Guiming Wang, Kristine O. Evans, Qingmin Meng, Jimmy D. Taylor

United States Department of Agriculture Wildlife Services: Staff Publications

Species distribution models and habitat suitability models (HSMs) have become a popular tool in the conservation of biodiversity. However, the ability to predict species spatial distributions at sites beyond the data source sites (i.e., spatial transferability) is critical for the applications of HSMs in the management and conservation of rare or endangered species. The main objective of our study was to assess the predictive performance and spatial transferability of expert opinion models (EOMs). To build EOMs, we identified through extensive literature reviews 17 key landscape variables to characterize habitat use by American beaver (Castor canadensis). We developed 31 pairwise opinion …

Evidence For Continental-Scale Dispersal Of Antimicrobial Resistant Bacteria By Landfill-Foraging Gulls, Christina A. Ahlstrom, Mariëlle L. Van Toor, Hanna Woksepp, Jeffrey C. Chandler, John A. Reed, Andrew B. Reeves, Jonas Waldenström, Alan B. Franklin, David C. Douglas, Jonas Bonnedahl, Andrew M. Ramey

United States Department of Agriculture Wildlife Services: Staff Publications

Anthropogenic inputs into the environment may serve as sources of antimicrobial resistant bacteria and alter the ecology and population dynamics of synanthropic wild animals by providing supplemental forage. In this study, we used a combination of phenotypic and genomic approaches to characterize antimicrobial resistant indicator bacteria, animal telemetry to describe host movement patterns, and a novel modeling approach to combine information fromthese diverse data streams to investigate the acquisition and long-distance dispersal of antimicrobial resistant bacteria by landfill-foraging gulls. Our results provide evidence that gulls acquire antimicrobial resistant bacteria from anthropogenic sources, which they may subsequently disperse across and between …

Evaluating Potential Effects Of Solar Power Facilities On Wildlife From An Animal Behavior Perspective, Rachel Y. Chock, Barbara Clucas, Elizabeth K. Peterson, Bradley Blackwell, Daniel T. Blumstein, Kathleen Church, Esteban Fernández-Juricic, Gabriel Francescoli, Alison L. Greggor, Paul Kemp, Gabriela M. Pinho, Peter M. Sanzenbacher, Bruce A. Schulte, Pauline Toni

United States Department of Agriculture Wildlife Services: Staff Publications

Solar power is a renewable energy source with great potential to help meet increasing global energy demands and reduce our reliance on fossil fuels. However, research is scarce on how solar facilities affect wildlife. With input from professionals in ecology, conservation, and energy, we conducted a research-prioritization process and identified key questions needed to better understand impacts of solar facilities on wildlife. We focused on animal behavior, which can be used to identify population responses before mortality or other fitness consequences are documented. Behavioral studies can also offer approaches to understand the mechanisms leading to negative interactions (e.g., collision, singeing, …

Multi-Level Movement Response Of Invasive Wild Pigs (Sus Scrofa) To Removal, Guillaume Bastille-Rousseau, Peter E. Schlichting, David A. Keiter, Joshua B. Smith, John C. Kilgo, George Wittemyer, Kurt C. Vercauteren, James C. Beasley, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

BACKGROUND: Lethal removal of invasive species, such as wild pigs (Sus scrofa), is often the most efficient approach for reducing their negative impacts. Wild pigs are one of the most widespread and destructive invasive mammals in the USA. Lethal management techniques are a key approach for wild pigs and can alter wild pig spatial behavior, but it is unclear how wild pigs respond to the most common removal technique, trapping.We investigated the spatial behavior of wild pigs following intensive removal of conspecifics via trapping at three sites within the Savannah River Site, SC, USA. We evaluated changes in …

Food Habits Of Wintering Double-Crested Cormorants In The Mississippi Delta, Terrel W. Christie, Brian S. Dorr, J. Brian Davis, Luke A. Roy, Carole R. Engle, Katie Hanson-Dorr, Anita M. Kelly

United States Department of Agriculture Wildlife Services: Staff Publications

Given its ubiquity, it is not surprising that agriculture, including fin fish aquaculture, contributes to food webs worldwide and is used by numerous wildlife for foraging and meeting other needs. Double-crested Cormorants (Phalacrocorax auritus) impact United States commercial aquaculture and are considered the primary avian predator in catfish (Ictalurus spp.) aquaculture facilities in the Mississippi Delta. Recent changes in aquaculture practices, regulatory policies, and decreased overall hectares in production prompted this study that assessed cormorant consumption of catfish in relation to their night roosts through surveys and diet analysis. Cormorants were collected from night roosts from October …

Principal Economic Effects Of Cormorant Predation On Catfish Farms, Carole R. Engle, Terrel W. Christie, Brian S. Dorr, Ganesh Kumar, Luke A. Roy, Anita M. Kelly

United States Department of Agriculture Wildlife Services: Staff Publications

Substantial economic losses of farmed catfish to fish-eating birds such as the double-crested cormorant, Phalacrocorax auritus, continue to be reported on U.S. catfish farms. An economic analysis was conducted of the on-farm effects of both the increased expenditures to scare fish-eating birds from catfish farms and of the value of the catfish that were consumed by cormorants. A survey was conducted of U.S. catfish farmers in the Delta region of Mississippi and Arkansas, to obtain farm-level data on expenditures to scare birds. Estimations of the lost revenue from catfish consumed by cormorants were developed from a concurrent study on …

Environmental Correlates Of Genetic Variation In The Invasive European Starling In North America, Natalie R. Hofmeister, Scott J. Werner, Irby J. Lovette

United States Department of Agriculture Wildlife Services: Staff Publications

Populations of invasive species that colonize and spread in novel environments may differentiate both through demographic processes and local selection. European starlings (Sturnus vulgaris) were introduced to New York in 1890 and subsequently spread throughout North America, becoming one of the most widespread and numerous bird species on the continent. Genome-wide comparisons across starling individuals and populations can identify demographic and/or selective factors that facilitated this rapid and successful expansion. We investigated patterns of genomic diversity and differentiation using reduced-representation genome sequencing of 17 winter-season sampling sites. Consistent with this species' high dispersal rate and rapid expansion history, …

Continental-Scale Dynamics Of Avian Influenza In U.S. Waterfowl Are Driven By Demography, Migration, And Temperature, Erin E. Gorsich, Colleen T. Webb, Andrew A. Merton, Jennifer A. Hoeting, Ryan S. Miller, Matthew Farnsworth, Seth R. Swafford, Thomas J. Deliberto, Kerri Pedersen, Alan B. Franklin, Robert G. Mclean, Kenneth R. Wilson, Paul Doherty

United States Department of Agriculture Wildlife Services: Staff Publications

Emerging diseases of wildlife origin are increasingly spilling over into humans and domestic animals. Surveillance and risk assessments for transmission between these populations are informed by a mechanistic understanding of the pathogens in wildlife reservoirs. For avian influenza viruses (AIV), much observational and experimental work in wildlife has been conducted at local scales, yet fully understanding their spread and distribution requires assessing the mechanisms acting at both local, (e.g., intrinsic epidemic dynamics), and continental scales, (e.g., long-distance migration). Here, we combined a large, continental-scale data set on low pathogenic, Type A AIV in the United States with a novel network-based …

Embracing Dynamic Models For Gene Drive Management, Andrew J. Golnar, Emily W. Ruell, Alun L. Lloyd, Kim M. Pepin

United States Department of Agriculture Wildlife Services: Staff Publications

Robust methods of predicting how gene drive systems will interact with ecosystems is essential for safe deployment of gene drive technology. We describe how quantitative tools can reduce risk uncertainty, streamline empirical research, guide risk management, and promote cross-sector collaboration throughout the process of gene drive technology development and implementation.

Gene drive technologies, although diverse in design and mode of action, are molecular architectures that promote the transmission of genetic information between generations. In theory, the release of one gene-drive-modified organism (GDMO) has the potential to irreversibly alter species, ecosystems, and environmental processes at a global scale (although in practice …

Temporal And Spatial Blood Feeding Patterns Of Urban Mosquitoes In The San Juan Metropolitan Area, Puerto Rico, Matthew W. Hopken, Limarie J. Reyes-Torres, Nicole Scavo, Antoinette J. Piaggio, Zaid Abdo, Daniel Taylor, James Pierce, Donald A. Yee

United States Department of Agriculture Wildlife Services: Staff Publications

Simple Summary: Understanding the biodiversity of urban ecosystems is critical for management of invasive and pest species, conserving native species, and disease control. Mosquitoes (Culicidae) are ubiquitous and abundant in urban ecosystems, and rely on blood meals taken from vertebrates. We used DNA from freshly blood-fed mosquitoes to characterize the diversity of vertebrate host species in the San Juan Metropolitan Area, Puerto Rico. We collected two mosquito species that fed on a variety of vertebrates. Culex quinquefasciatus fed on 17 avian taxa (81.2% of blood meals), seven mammalian taxa (17.9%), and one reptilian taxon (0.85%). Aedes aegypti blood meals were …

Population Genomic Transformations Induced By Isolation Of Wild Bird Avian Influenza Viruses (Orthomyxoviridae) In Embryonated Chicken Eggs, Matthew W. Hopken, Antoinette J. Piaggio, K. L. Pabilonia, James Pierce, Theodore Anderson, Courtney Pierce, Zaid Abdo

United States Department of Agriculture Wildlife Services: Staff Publications

Isolation and cultivation of wild-type viruses in model organism cells or tissues is standard practice in virology. Oftentimes, the virus host species is distantly related to the species from which the culture system was developed. Thus, virus culture in these tissues and cells basically constitutes a host jump, which can lead to genomic changes through genetic drift and/or adaptation to the culture system. We directly sequenced 70 avian influenza virus (Orthomyxoviridae) genomes from oropharyngeal/cloacal swabs collected from wild bird species and paired virus isolates propagated from the same samples following isolation in specific-pathogen-free embryonated chicken eggs. The data were analyzed …

Variation In Angiostrongylus Cantonensis Infection In Definitive And Intermediate Hosts In Hawaii, A Global Hotspot Of Rat Lungworm Disease, Chris Niebuhr, Shane R. Siers, Israel Leinbach, Lisa M. Kaluna, Susan I. Jarvi

United States Department of Agriculture Wildlife Services: Staff Publications

Angiostrongylus cantonensis (rat lungworm) is a tropical and subtropical parasitic nematode, with infections in humans causing angiostrongyliasis (rat lungworm disease), characterized by eosinophilic meningitis. Hawaii has been identified as a global hotspot of infection, with recent reports of high infection rates in humans, as well as rat definitive and snail intermediate hosts. This study investigated variation in A. cantonensis infection, both prevalence and intensity, in wild populations of two species of rats (Rattus exulans and R. rattus) and one species of snail (Parmarion martensi). An overall infection prevalence of 86.2% was observed in P. martensi and …

Estimation Of Wildlife Damage From Federal Crop Insurance Data, Sophie Mckee, Stephanie A. Shwiff, Aaron M. Anderson

United States Department of Agriculture Wildlife Services: Staff Publications

BACKGROUND: Wildlife damage to crops is a persistent and costly problem for many farmers in the USA. Most existing estimates of crop damage have relied on direct assessment methods such as field studies conducted by trained biologists or surveys distributed to farmers. In this paper, we describe a new method of estimating wildlife damage that exploits federal crop insurance data. We focused our study on four crops: corn, soybean, wheat, and cotton, chosen because of their economic importance and their vulnerability to wildlife damage.

RESULTS: We determined crop-raiding hot spots across the USA over the 2015–2019 period and identified the …

Inefficiency Of Anthraquinone-Based Avian Repellents When Applied To Sunflower: The Importance Of Crop Vegetative And Floral Characteristics In Field Applications, Brandon Kaiser, Burton L. Johnson, Mike Ostlie, Scott J. Werner, Page E. Klug

United States Department of Agriculture Wildlife Services: Staff Publications

BACKGROUND: Blackbirds (Icteridae) cause significant damage to sunflower (Helianthus annuus L.) prompting the need for effective management tools. Anthraquinone-based repellents can reduce feeding by > 80% in laboratory settings, but require birds to learn the negative association through repellent ingestion. We evaluated an anthraquinone-based repellent applied directly to mature sunflower plants for its ability to reduce bird damage. We used captive male red-winged blackbirds (Agelaius phoeniceus) to evaluate efficacy of two anthraquinone-based formulations in varying concentrations and applied in a manner attainable by sunflower producers. We also assessed field application methods for repellent coverage and anthraquinone residues when …