Controlling nuisance black vultures in Missouri

Vultures play a critical role in the environment as scavengers of carrion. They provide an important ecological service in consuming carrion which reduces the risk of diseases from spreading in the environment. Turkey and black vultures, as with all other wildlife, will take advantage of resources available to them, unfortunately this can cause issues when it involves human dwellings and in some cases livestock operations. Black vultures, in particular, are increasing in population and their aggressive nature can cause problems for livestock producers in Missouri. Unlike their less-aggressive cousin, the turkey vulture, black vultures are known to gang up and prey on calves, piglets, lambs, and newborn goats. They sometimes attack cows that are ill or giving birth. Black vultures can also cause property damage and problems by damaging rubber seals and windshield wipers on parked vehicles, canvas awnings and seating on boats, and rubber or vinyl materials on rooftops. Legally, black vultures are protected under the federal Migratory Bird Treaty Act of 1918 (fws.gov/laws /lawsdigest/migtrea.html). Their migratory range extends for thousands of miles from North America to the lower portions of South America, crossing national boundaries. It is illegal to harm or take (kill) black vultures without a permit.Written by Robert A. Pierce II (MU Extension State Wildlife and Fisheries Specialist), Travis Guerrant (State Director, USDA APHIS Wildlife Services-Missouri/Iowa)Includes bibliographical reference

An efficient method of evaluating multiple concurrent management actions on invasive populations

Evaluating the efficacy of management actions to control invasive species is crucial for maintaining funding and to provide feedback for the continual improvement of management efforts. However, it is often difficult to assess the efficacy of control methods due to limited resources for monitoring. Managers may view effort on monitoring as effort taken away from performing management actions. We developed a method to estimate invasive species abundance, evaluate management effectiveness, and evaluate population growth over time from a combination of removal activities (e.g., trapping, ground shooting) using only data collected during removal efforts (method of removal, date, location, number of animals removed, and effort). This dynamic approach allows for abundance estimation at discrete time points and the estimation of population growth between removal periods. To test this approach, we simulated over 1 million conditions, including varying the length of the study, the size of the area examined, the number of removal events, the capture rates, and the area impacted by removal efforts. Our estimates were unbiased (within 10% of truth) 81% of the time and were correlated with truth 91% of the time. This method performs well overall and, in particular, at monitoring trends in abundances over time. We applied this method to removal data from Mingo National Wildlife Refuge in Missouri from December 2015 to September 2019, where the management objective is elimination. Populations of feral swine on Mingo NWR have fluctuated over time but showed marked declines in the last 3–6 months of the time series corresponding to increased removal pressure. Our approach allows for the estimation of population growth across time (from both births and immigration) and therefore, provides a target removal rate (above that of the population growth) to ensure the population will decline. In Mingo NWR, the target monthly removal rate is 18% to cause a population decline. Our method provides advancement over traditional removal modeling approaches because it can be applied to evaluate management programs that use a broad range of removal techniques concurrently and whose management effort and spatial coverage vary across time

Evaluation of the Effect of Hydrated Lime on the Scavenging of Feral Swine (\u3ci\u3eSus Scrofa\u3c/i\u3e) Carcasses and Implications for Managing Carcass-Based Transmission of African Swine Fever Virus

African swine fever (ASF) is a devastating hemorrhagic disease marked by extensive morbidity and mortality in infected swine. The recent global movement of African swine fever virus (ASFV) in domestic and wild swine (Sus scrofa) populations has initiated preparedness and response planning activities within many ASF-free countries. Within the US, feral swine are of utmost concern because they are susceptible to infection, are wide-spread, and are known to interact with domestic swine populations. African swine fever virus is particularly hardy and can remain viable in contaminated carcasses for weeks to months; therefore, carcass-based transmission plays an important role in the epidemiology of ASF. Proper disposal of ASF-infected carcasses has been demonstrated to be paramount to curbing an ASF outbreak in wild boar in Europe; preparedness efforts in the US anticipate carcass management being an essential component of control if an introduction were to occur. Due to environmental conditions, geographic features, or limited personnel, immediately removing every carcass from the landscape may not be viable. Hydrated lime converts to calcium carbonate, forming a sterile crust that may be used to minimize pathogen amplification. Any disturbance by scavenging animals to the sterile crust would nullify the effect of the hydrated lime; therefore, this pilot project aimed to evaluate the behavior of scavenging animals relative to hydrated lime-covered feral swine carcasses on the landscape. At two of the three study sites, hydrated limetreated carcasses were scavenged less frequently compared to the control carcasses. Additionally, the median time to scavenging was 1 d and 6 d for control versus hydrated lime-treated carcasses, respectively. While results of this study are preliminary, hydrated lime may be used to deter carcass disruption via scavenging in the event that the carcass cannot be immediately removed from the landscape

Green Roofs in the Airport Environment: Pleasant Dreams or Nightmares?

Green roofs on buildings are becoming very popular in urban areas of the United States. Public benefits of green roof projects include stormwater runoff reduction, improved water quality, reduced urban heat island effects, and aesthetic values. Several green roofs have been constructed in downtown Chicago and large-scale green roofs are currently being planned and implemented at O’Hare International Airport (ORD). Similar to any airport landscaping, green roofs on buildings in the airport environment might attract wildlife hazardous to aviation and could increase the risk of bird-aircraft collisions. No information currently exists in regard to this potential problem. During 2007–2008, we conducted a study to evaluate the wildlife use of a newly constructed green roof on the Airfield Rescue and Fire Fighting building at ORD. This green roof was approximately 320 m2 in area and consisted of Sedum spp. for vegetation. Wildlife surveys were conducted on the green roof each week from January 2007 to March 2008. During the 13-month study, a total of 157 birds were observed flying over or using the green roof; 34% were using the green roof itself, whereas 66% were flying by the green roof and did not exhibit any perceived interest. Of the birds actually using the green roof, 72%, 13%, and 9% were killdeer, European starlings, and mourning doves, respectively. Killdeer nested on green roof, whereas the other species were perched or loafing. Birds used the green roof only between May and October. Overall, wildlife use of the green roof was minimal and appeared to be similar to use of adjacent buildings with traditional roofs. Although green roofs with vegetation types that offer forage and/or cover to birds might be attractive, the Sedum spp.-vegetated green roof in this study did not attract wildlife hazardous to aviation or increase the risk of bird strikes

Benefits to Rare Plants and Highway Safety from Annual Population Reductions of a “Native Invader,” White-Tailed Deer, in a Chicago-Area Woodland

Overabundant white-tailed deer are one of the most serious threats to woodland plant communities in the Chicago area. Moreover, the abundant deer in a highly populated area causes economic harm and poses hazards to human safety through collisions with vehicles. The artificial conditions causing the overabundance and resulting consequences qualify the white-tailed deer in the Chicago area to be considered as native invaders . We examined the benefits of culling deer at a Chicago-area woodland preserve by comparing browse rates on four endangered plant species from years before culling began with years with culling. We also examined deer-vehicle collision and traffic flow rates on area roads from years before culling began and years with culling to assess whether population reductions may have benefited road safety in the area. All four endangered plant species (three orchid species and sweet fern) had lower browse rates in years with culls, although the decreased browsing rates were statistically distinguishable for only two of the species (grass pink orchid and sweet fern). After first verifying that traffic flow rates did not decrease from pre-cull years to years with culls, we analyzed the Illinois Department of Transportation data from area roads based on deer-vehicle collisions causing \u3eUS$500 in damage and showed a one-third reduction in deer-vehicle collisions. An economic analysis showed a cost savings during the cull years of US$0.6 million for reducing browsing to just these four monitored plant species and the reduction in deer-vehicle collisions

Managing Raptors to Reduce Wildlife Strikes at Chicago’s O’Hare Interna-tional Airport

Wildlife-aircraft collisions (wildlife strikes) have increased nationally over the past 22 years; denoted in the National Wildlife Strike Database that has been maintained by the Federal Aviation Administration (FAA) since 1990. Increasing wildlife populations and air traffic coupled with quieter, faster aircraft create a significant risk to aviation safety; the cost to the civil aviation industry is an esti-mated $718 million dollars annually. USDA/APHIS/Wildlife Services provides technical and direct as-sistance to over 785 airports and airbases around the United States, including Chicago’s O’Hare Interna-tional Airport (ORD). At ORD, raptors are the most commonly struck bird guild accounting for 25% of all damaging strikes in 2011. An integrated wildlife damage management program is implemented at ORD to reduce the presence of wildlife on the airfield, consequently lowering the risk of wildlife strikes. Professional airport wildlife biologists at ORD concentrate much of their efforts on raptor damage man-agement due to the high strike risk these birds pose to aircraft on the airfield itself. A variety of tech-niques are currently used to manage raptor populations at ORD

Mitigation Translocation of Red-Tailed Hawks to Reduce Raptor–Aircraft Collisions

Translocation of problematic individual animals is commonly used to reduce human–wildlife conflicts, especially to reduce the presence or abundance of raptors within airport environments, where they pose a risk to safe aircraft operations. Although this method has strong public support, there have been no scientific evaluations of its efficacy or to determine which factors might influence the return of translocated birds to the airport. We conducted a study to determine which biological and logistical factors might influence the return of red-tailed hawks (Buteo jamaicensis) translocated from Chicago’s O’Hare International Airport (ORD) during 2010–2013. We live-captured and translocated red-tailed hawks various distances from the ORD airfield and monitored for returning birds. We found the odds of hawk return increased by 2.36 (95% CI=0.99–5.70) times for older birds (\u3e1 yr of age) relative to younger birds (≤1yr of age). Odds of hawk return went up 4.10 (95% CI=0.75–22.2) times when translocations were conducted during the breeding season relative to the non-breeding season. The odds of hawk return increased 11.94 (95% CI=3.29–43.38) times for each subsequent translocation event involving the same hawk. The cost of 1 translocation event to the release sites that were 81, 121, 181, and 204 km from ORD was $213,$284, $362, and$426, respectively. Management programs that use release sites 80 km from the airport minimize translocation events to include only younger birds during the non-breeding season, and undertake only 1 translocation event for an individual hawk would increase program efficacy and greatly reduce program implementation costs. The decision matrix regarding the use of a raptor trapping and translocation program involves a variety of biological, logistical, economic, and sociopolitical variables. This study represents an important first step in providing a scientific foundation for informing such management decisions

Comparing Management Programs to Reduce Red–tailed Hawk Collisions with Aircraft

Wildlife-aircraft collisions (wildlife strikes) pose a serious safety risk to aircraft. Raptors (i.e., hawks and owls) are one of the most frequently struck guilds of birds within North America. Although raptors (most notably red-tailed hawks [Buteo jamaicensis]) are commonly managed at most airports and military bases, there is no scientific information available regarding comparisons of the efficacy of raptor management programs for reducing raptor-aircraft collisions. Therefore, we conducted a study to examine the efficacy of 2 raptor hazard management programs implemented at Chicago\u27s O\u27Hare International Airport (ORD). The first raptor management program (Phase I) occurred during January 2010–June 2013 and was characterized by intensive and sustained live-trapping and translocation efforts. The second raptor management program (Phase II) occurred during July 2013–December 2016 and involved live-trapping and translocation of specific age classes and increased lethal removal of problematic individual hawks. Compared with Phase I, there were 47% fewer red-tailed hawk strikes (52 in Phase I and 28 in Phase II) and 67% fewer damaging red-tailed hawk strikes (6 in Phase I and 2 in Phase II) during Phase II of the management programs. Our findings demonstrate that airport wildlife management decisions based on scientific data and biological information can aid in reducing wildlife strikes, financial losses, and ultimately airport liability while increasing human safety. The decision matrix regarding the components of an airport raptor hazard management program involves a variety of biological, geographic, logistical, economic, and socio-political variables. Our study provides a scientific foundation for informing such management decisions. Published 2021. This article is a U.S. Government work and is in the public domain in the USA

Efficacy of Avian Radar Systems for Tracking Birds on the Airfield of a Large International Airport

Avian radar technologies have the potential to serve an important role in the quantification of bird movements and determining patterns of bird use in areas where human–wildlife conflicts might occur (e.g., airports, wind-energy facilities). However, capabilities and limitations of these technologies are relatively unknown and ground-truthing studies are needed to help wildlife managers understand the biological meaning of radar information. We evaluated the efficacy of 3 X-band marine radar sensors for tracking birds and flocks of birds observed on the airfield at Chicago’s O’Hare International Airport, USA, during March 2011– November 2012.We used specific information regarding field observations of birds or flocks to determine how frequently the 3 radar sensors provided corresponding tracks of these avian targets. In addition, we examined various factors to determine if they had any influence on the frequency of correspondence between visual observations and radar tracks. Of the 972 sightings of individual birds (49%) or flocks of birds (51%) by observers on the airfield that had the potential to be observed by the radar, 143 (15%) were tracked by_1 radar sensor. All confirmed tracks of individual birds or flocks were _4.8km from these radars. Among the 3 radar sensors, larger bodied bird species, bird/flocks flying at higher altitudes, and bird/flocks closer to the radars increased the ability of those units to track avian targets. This study provides new information regarding the performance of radar systems for tracking birds on the airfield of one of the largest and busiest airports in the world. Published 2018. This article is a U.S. Government work and is in the public domain in the USA

Monitoring Raptor Movements with Satellite Telemetry and Avian Radar Systems: An Evaluation for Synchronicity

Avian radar technologies have the potential to serve an important role in the quantification of bird movements and determining patterns of bird use in areas where human–wildlife conflicts might occur (e.g., airports, wind energy facilities). Ground-truthing studies are needed to help wildlife managers understand the biological meaning of radar information, as the capabilities and limitations of these technologies are relatively unknown. We conducted a study to evaluate the efficacy of three X-band marine radar sensors for tracking red-tailed hawks (Buteo jamaicensis) on or near the airfield at Chicago’s O’Hare International Airport from September 2010 to May 2014. Specific information regarding red-tailed hawk locations derived from satellite telemetry was used to determine how frequently the three radar sensors provided corresponding tracks of these avian targets (i.e., synchronized monitoring). We examined various factors (e.g., bird altitude and distance to the radar) to determine if they had any influence on the frequency of synchronicity between satellite telemetry locations and radar tracks. We found evidence that as the distance between a hawk and the radars increased, the radars’ ability to detect and track known avian targets decreased. Overall, the frequency of synchronization events for red-tailed hawks was low. Of the 1977 red-tailed hawk locations that should have been visible to the radar sensors, 51 of these bird movements were tracked by at least one of the radar sensors (2.6%). This study provides a new methodology for evaluating the performance of radar systems for tracking birds and determining what factors might influence overall performance