VEGETATION MANAGEMENT APPROACHES FOR REDUCING WILDLIFE-AIRCRAFT COLLISIONS

Wildlife-aircraft collisions (wildlife strikes) pose safety risks to aircraft and cost civil aviation over $390 million annually in the USA. We reviewed the results of prior studies to summarize the vegetation management techniques that have proven effective for wildlife strike reduction or have shown potential for achieving the same goal. Habitat components that may affect wildlife use of airports include food, cover, water, and loafing areas. Improperly managed natural and ornamental vegetation on airports can be important attractants for wildlife that pose strike hazards. However, effective vegetation management can reduce these hazards. Maintaining tall herbaceous vegetation may reduce the availability or attractiveness of loafing and feeding sites for some species of birds such as gulls. However, this management strategy may also increase cover and food resources for other hazardous species. Thus, optimum vegetation height management strategies require further research and may be site-specific. Food availability may be reduced by replacing attractive vegetation such as palatable forage with less attractive vegetation. Vegetation management may also include removal of vegetative cover for deer and small mammals and nesting sites for birds such as woody vegetation. Removal of ornamental trees and shrubs may also be used to reduce availability of perches for flocking birds and large predatory birds. Despite more than 30 years of substantive discussion on the importance of these habitat management techniques, few reliable studies of the effectiveness of these techniques have been conducted. Specific needs for reliable data include definitive studies of the response of entire bird communities to vegetation height management in the USA, and field evaluations of vegetation types thought to be unattractive to wildlife under operational airport conditions

VEGETATION MANAGEMENT APPROACHES FOR REDUCING WILDLIFE-AIRCRAFT COLLISIONS

Wildlife-aircraft collisions (wildlife strikes) pose safety risks to aircraft and cost civil aviation over $390 million annually in the USA. We reviewed the results of prior studies to summarize the vegetation management techniques that have proven effective for wildlife strike reduction or have shown potential for achieving the same goal. Habitat components that may affect wildlife use of airports include food, cover, water, and loafing areas. Improperly managed natural and ornamental vegetation on airports can be important attractants for wildlife that pose strike hazards. However, effective vegetation management can reduce these hazards. Maintaining tall herbaceous vegetation may reduce the availability or attractiveness of loafing and feeding sites for some species of birds such as gulls. However, this management strategy may also increase cover and food resources for other hazardous species. Thus, optimum vegetation height management strategies require further research and may be site-specific. Food availability may be reduced by replacing attractive vegetation such as palatable forage with less attractive vegetation. Vegetation management may also include removal of vegetative cover for deer and small mammals and nesting sites for birds such as woody vegetation. Removal of ornamental trees and shrubs may also be used to reduce availability of perches for flocking birds and large predatory birds. Despite more than 30 years of substantive discussion on the importance of these habitat management techniques, few reliable studies of the effectiveness of these techniques have been conducted. Specific needs for reliable data include definitive studies of the response of entire bird communities to vegetation height management in the USA, and field evaluations of vegetation types thought to be unattractive to wildlife under operational airport conditions

Are birds scared by rotating mirrors?

Blackbirds (Icteridae) create human health and safety concerns when roosting in large numbers near airports or other urban areas. Therefore, there is considerable demand for effective nonlethal techniques to deter these birds. We tested the effectiveness of rotating mirrors (Peaceful Pyramid®) to keep blackbirds away from decoy traps. Mirrors were in place on traps for 5 consecutive days with control traps having similar a device in place but without mirrors. The total number of birds captured in traps with clear mirrors and control traps did not (P = 0.62) differ. When red mirrors were used, the total number of birds captured was lower (P = 0.01) in treated than control traps. Similar (P ≥ 0.42) numbers of brown-headed cowbirds (Molothrus ater) were caught in control or traps treated with either clear or red mirrors. Fewer (P = 0.01) common grackles (Quiscalus quiscula) were captured in traps with red mirrors as compared to control traps. Under the test criteria (i.e., food and flock attractants), Peaceful Pyramids®did not reduce the number of cowbirds captured in decoy traps. However, fewer birds, specifically common grackles, were captured at traps with red mirrors; we conclude that there was at least a species-specific initial reaction to red mirror

Gulls

Abundant gull (Figure 1) populations in North America have led to a variety of conflicts with people. Gulls cause damage at aquaculture facilities and other properties, and often collide with aircraft. Their use of structures on and near water results in excessive amounts of bird droppings on boats and docks. Their presence near outdoor dining establishments, swimming beaches, and recreational sites can lead to negative interactions with people. Large amounts of gull fecal material pollutes water and beaches resulting in drinking water contamination and swim bans. A combination of dispersal techniques, exclusion and limited lethal control may reduce damage to an acceptable level. No single management method to prevent gull conflicts works all the time or in all settings. Wildlife management methods should be integrated so that one method enhances the effect of another. For example, frightening devices often are more effective when done in conjunction with habitat modification (e.g., removal of food resources or roosting habitat) to make a site less attractive to gulls. Likewise, exclusion devices, such as overhead wires, work better when combined with covering or removing food resources. Gulls are classified as a migratory bird species and are protected by federal and, in most cases, state laws. In the United States, gulls may be taken only with a permit issued by the U.S. Fish and Wildlife Service. Occasionally, an additional permit is required from the state wildlife management agency. Permits are issued only after dispersal and other non-lethal damage management methods have been employed and proven ineffective at resolving the conflicts. No federal permit is needed, however, to frighten or mechanically exclude gulls

Black Vulture Conflict and Management in the United States: Damage Trends, Management Overview, and Research Needs

Contrary to rapid declines of many vulture (Accipitridae, Cathartidea) species worldwide, black vulture (Coragyps atratus) populations are increasing and expanding their range in North America. Vultures exhibit complex behaviors and can adapt to any human-dominated landscape or land use. These traits, combined with population growth and range expansion, have contributed to increased human–vulture conflicts. Our goal was to summarize the current status and trends in human–black vulture conflicts (hereafter human–vulture conflicts), review available management strategies, identify knowledge gaps, and provide recommendations to enhance management and understanding of this species and the associated conflicts. We found human–vulture conflicts are increasing in agriculture (livestock), private and public property (both personal and infrastructure-based), and threats to human health and safety. The greatest increases in conflicts were reported in agriculture and private and public property damage. Regarding livestock depredation, good progress has been made toward assessing producer perceptions of the conflicts, including estimates of economic damage and mitigation strategies, but a basic understanding of the underlying mechanism driving the conflict and advancing strategies to mitigate damage is lacking. For damaged property, little information is available regarding economic losses and perceptions of stakeholders who are experiencing the damage, and most of the tools recommended for mitigating this damage have not been rigorously evaluated. Regarding human health and safety, recent research quantifying flight behavior of black vultures has direct implications for reducing aircraft collision risks. However, it is unclear what factors influence roost site selection and the most effective means to leverage the sensory ecology of the species to mitigate risks. We identify additional knowledge gaps and research needs that if addressed could increase managers’ understanding of black vulture ecology and facilitate enhanced management of this species while simultaneously allowing for the species to provide valuable ecosystem services

DEFINING AND REDUCING WILDLIFE HAZARDS TO AVIATION IN THE USA

The U.S. Department of Agriculture’s National Wildlife Research Center (NWRC), through an interagency agreement with the U.S. Federal Aviation Administration (FAA), conducts a national research program to define and reduce bird and other wildlife hazards to aircraft. The goal is to provide the FAA and airports nationwide with a scientific foundation for policies and recommendations related to wildlife and aviation safety. Research tasks conducted by NWRC under the agreement include: 1) investigations of habitat management and land-use practices on and near airports to reduce bird activity; 2) development and evaluation of bird repellent and frightening methods for airports; 3) management and analysis of the National Wildlife Strike Database for civil aviation; and 4) development of publications, including a manual on wildlife hazard management, for use by airport operators nationwide. The research, coordinated by NWRC’s Sandusky, Ohio Field Station, has resulted in over 100 scientific publications since 1992. Recent highlights include 1) development of a wildlife strike database for civil aviation with about 28,000 strike reports, 1990-1999; 2) publication of a report, based on analyses of data in the bird strike database, which indicated wildlife collisions with aircraft cost U.S. civil aviation over $300 million/year, 1990-1998; 3) partnership with private industry to develop chemical repellents for use against Canada geese on airports; 4) development of management program at JFK International Airport, New York, that resulted in a 90% reduction in gull-aircraft collisions; and 5) publication of a comprehensive manual for airport personnel entitled “Wildlife Hazard Management at Airports”

Double-Crested Cormorant Distribution on Catfish Aquaculture in the Yazoo River Basin of Mississippi

ABSTRACT Estimating the catfish aquaculture production losses that can be attributed to double-crested cormorants (Phalacrocorax auritus) has proved problematic because knowledge of the distribution of cormorants on catfish aquaculture is lacking. We evaluated use versus availability of various production pond types and landscape-scale factors affecting the distribution of cormorants on channel catfish (Ictalurus punctatus) aquaculture facilities in Mississippi, USA. Cormorant distribution on aquaculture pond types indicated selection against brood-fish ponds, neutral selection on fingerling ponds, and selection for food-fish ponds (n ¼ 29, Chesson's a ¼ 0.19, 0.36, and 0.45, respectively). Modeled and validated correct classification rate (CCR) of general linear mixed models of cormorant occupancy of clusters of catfish ponds indicated seasonality of use and roost distance from aquaculture ponds was predictive (CCR ¼ 81% and 71%, respectively). Modeled and validated ordinal models of levels of use (low, moderate, high) were less predictive (CCR ¼ 67% and 59%, respectively). However, predictability within use levels for the validation data set was mixed, ranging from 0.19 to 0.86. Odds ratios indicate both higher risk of occupancy and levels of use over the period February-April relative to October. Management efforts targeted during this time frame will have the greatest impact in reducing depredation losses. The majority of cormorants occurred on food-fish ponds. Consequently estimates of economic loss should be revisited and refined based on distributional information provided in this study. Published 2012. This article is a U.S. Government work and is in the public domain in the USA

Foraging Ecology and Distribution of Scaup (Aythya spp.) on Arkansas Commercial Baitfish and Sportfish Farms

Lesser Scaup (Aythya affinis)and Greater Scaup (Aythya marila) have been reported to consume substantial quantities of golden shiners (Notemigonus crysoleucas), fathead minnows (Pimephales promelas), goldfish (Carassius auratus), and sunfish (Lepomis spp.) produced on Arkansas commercial baitfish and sportfish farms. The goals of this study were to investigate foraging ecology and distribution of Scaup at these facilities, and use this information to assist producers in administering bird harassment efforts more efficiently. During typical wintering period for Scaup in Arkansas (November-March), we conducted approximately 1,400 pond surveys to estimate abundance and distribution of scaup on farms in 2016-2017 and 2017-2018. Information related to pond size, fish species, fish size, and stocking density, were also obtained to enable a more detailed analysis of Scaup use. We also collected 561 Scaup from these facilities to quantify the proportion of diet obtained from fish. There was an increase in Scaup abundance and fish consumption between the first to the second winter, likely attributed to cooler temperatures during the second winter. Our distribution model predicted an increased probability of Scaup use on larger ponds containing high densities of fish, while diet analysis indicated increased fish consumption during colder winter periods. Our results can be used by farm managers to designate resources for bird harassment to particular locations and times of the winter when scaup are more likely to negatively impact the fish crop

Reducing Impacts of Double-crested Cormorants to Natural Resources in Central New York: A Review of a Collaborative Research, Management, and Monitoring Program

Double-crested Cormorants (Phalacrocorax auritus) have used central New York waters for breeding and stopover habitats during migration since 1984. In response to public concern over Oneida Lake, the United States Department of Agriculture Wildlife Services and the New York State Department of Environmental Conservation initiated an integrated research, management and monitoring program aimed at mitigating cormorant impacts to fisheries and other natural resources in 1998. The history of this program was reviewed and efforts to reduce negative impacts of the Double-crested Cormorant population in central New York described. Management was successful, as demonstrated by a substantial decrease in cormorant use of Oneida Lake during spring, summer and fall seasons, and the apparent recovery of certain sportfish populations. Research identified cormorant movement patterns within and among water bodies and documented cormorant responses to hazing and other management techniques. The cormorant management program in central New York was intended to keep cormorant use of Oneida Lake at a level that prevents unsustainable impacts to fisheries populations

Reducing Impacts of Double-crested Cormorants to Natural Resources in Central New York: A Review of a Collaborative Research, Management, and Monitoring Program

Double-crested Cormorants (Phalacrocorax auritus) have used central New York waters for breeding and stopover habitats during migration since 1984. In response to public concern over Oneida Lake, the United States Department of Agriculture Wildlife Services and the New York State Department of Environmental Conservation initiated an integrated research, management and monitoring program aimed at mitigating cormorant impacts to fisheries and other natural resources in 1998. The history of this program was reviewed and efforts to reduce negative impacts of the Double-crested Cormorant population in central New York described. Management was successful, as demonstrated by a substantial decrease in cormorant use of Oneida Lake during spring, summer and fall seasons, and the apparent recovery of certain sportfish populations. Research identified cormorant movement patterns within and among water bodies and documented cormorant responses to hazing and other management techniques. The cormorant management program in central New York was intended to keep cormorant use of Oneida Lake at a level that prevents unsustainable impacts to fisheries populations.Keywords: Non-lethal management, Oneida Lake, Double-crested Cormorant, Harassment, Wildlife management, New York, Management, Monitorin