Composition and Diversity of Avian Communities Using a New Urban Habitat: Green Roofs

Green roofs on buildings are becoming popular and represent a new component of the urban landscape. Public benefits of green roof projects include reduced stormwater runoff, improved air quality, reduced urban heat island effects, and aesthetic values. As part of a city-wide plan, several green roofs have been constructed at Chicago’s O’Hare International Airport (ORD). Like some other landscaping features, green roofs on or near an airport might attract wildlife and thus increase the risk of bird–aircraft collisions. During 2007–2011, we conducted a series of studies to evaluate wildlife use of newly constructed green roofs and traditional (gravel) roofs on buildings at ORD. These green roofs were 0.04–1.62 ha in area and consisted of primarily stone crop species for vegetation. A total of 188 birds were observed using roofs during this research. Of the birds using green roofs, 66, 23, and 4 % were Killdeer, European Starlings, and Mourning Doves, respectively. Killdeer nested on green roofs, whereas the other species perched, foraged, or loafed. Birds used green roofs almost exclusively between May and October. Overall, avian use of the green roofs was minimal and similar to that of buildings with traditional roofs. Although green roofs with other vegetation types might offer forage or cover to birds and thus attract potentially hazardous wildlife, the stonecrop-vegetated green roofs in this study did not increase the risk of bird–aircraft collisions

Composition and Diversity of Avian Communities Using a New Urban Habitat: Green Roofs

Green roofs on buildings are becoming popular and represent a new component of the urban landscape. Public benefits of green roof projects include reduced stormwater runoff, improved air quality, reduced urban heat island effects, and aesthetic values. As part of a city-wide plan, several green roofs have been constructed at Chicago’s O’Hare International Airport (ORD). Like some other landscaping features, green roofs on or near an airport might attract wildlife and thus increase the risk of bird–aircraft collisions. During 2007–2011, we conducted a series of studies to evaluate wildlife use of newly constructed green roofs and traditional (gravel) roofs on buildings at ORD. These green roofs were 0.04–1.62 ha in area and consisted of primarily stone crop species for vegetation. A total of 188 birds were observed using roofs during this research. Of the birds using green roofs, 66, 23, and 4 % were Killdeer, European Starlings, and Mourning Doves, respectively. Killdeer nested on green roofs, whereas the other species perched, foraged, or loafed. Birds used green roofs almost exclusively between May and October. Overall, avian use of the green roofs was minimal and similar to that of buildings with traditional roofs. Although green roofs with other vegetation types might offer forage or cover to birds and thus attract potentially hazardous wildlife, the stonecrop-vegetated green roofs in this study did not increase the risk of bird–aircraft collisions

Great Lakes Restoration Initiative Activities in Illinois to Reduce Canada Goose Impacts on Lake Michigan

The Great Lakes Restoration Initiative (GLRI), led by the Environmental Protection Agency, was created in 2010 to address threats to the Great Lakes region. A convenient year-round water source and abundant food source of managed turf grass has resulted in an overabundance of Canada Geese (Branta canadensis) in Chicago City Parks within the watershed of Lake Michigan. The anthropogenic mediated benefit to goose populations and their associated damages qualifies Canada geese in Chicago as native invaders-where a native species is human induced to behave similar to invasive species. The objective of this project is to provide a long-term strategy to protect vegetation and reduce non-point source contamination from entering the nearshore waters of Lake Michigan, and as a byproduct improve human enjoyment of the parks. To accomplish this goal, the U.S. Department of Agriculture’s Wildlife Services (WS) program in cooperation with the Chicago Park District (CPD) continued, for the sixth year, to manage overabundant Canada goose populations in CPD parks with funding provided by GLRI. Between 2011 and 2016, we applied food grade corn oil to all Canada goose nests found within 24 sensitive lakefront parks in Chicago and successfully reduced hatching success and subsequent fledging. The number of nests found and treated during 2012 through 2016 has consistently been less than during the initial year of egg oiling in 2011. In March 2016, we treated a total of 115 nests containing 676 eggs with corn oil to prevent hatching; compared to 159 nests and 892 eggs in 2011. We applied a chemical application of the Anthraquinone-based foraging repellent, FlightControl® PLUS (FCP) to the grass every 3 weeks in 6 parks in an attempt to discourage geese from foraging and loafing in locations that directly drain into the nearshore water of Lake Michigan. To gauge the effectiveness of the FCP applications, we performed goose presence/behavior surveys in the 6 treated parks. The surveys helped to obtain a better understanding of how many geese were utilizing the untreated and treated areas and how many of those geese were consuming grass on the FCP treated areas. The surveys demonstrated that more geese used untreated areas compared to treated areas of the parks. A total of 5,511 geese were observed (3,221 in the untreated areas and 2,290 in the treated areas) during the survey period. While geese may be present in the treated areas, only 40% of all geese consumed grass in treated areas. Alternatively, 58% of all geese present in the untreated areas consumed grass. The surveys also showed that FCP treatments became less effective each week post spraying. The mean number of geese present and feeding in the treated areas showed a diminishing effectiveness from the FCP spraying on the treated areas across weeks. The statistical results confirmed this strong week-post-spray by treatment interaction. 21 The disparity in numbers of geese actually consuming grass within the treated versus untreated areas reflects that the FCP treatments were effective at deterring geese from consuming grass in FCP treated areas, but did not necessarily result in the birds dispersing away from FCP treated vegetation. Future applications of FCP are recommended where high concentrations of geese congregate on sensitive habitats or in areas of high public use along the lakefront. Continued population management through egg oiling is recommended to help prevent further environmental contamination and soil erosion in this sensitive Lake Michigan environment

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

Investigating nocturnal UAS treatments in an applied context to prevent gulls from nesting on rooftops

Ring‐billed (Larus delawarensis) and herring (L. argentatus) gulls are numerous and widespread in North America. These gulls rank among the top 9 species for risk of bird‐aircraft collisions (hereafter strikes). The ubiquitous presence of gulls in urban coastal environments, including rooftop nesting behavior, are factors impacting strike risk. Our purpose was to assess gull response to a small uncrewed aircraft system (UAS) in hazing flights at night during the nest‐building phase. We hypothesized that nocturnal UAS operation, like nocturnal predator disturbance, might reduce gull numbers and, thus, strike risk to aircraft. In spring 2021, we conducted UAS treatments over target roofs at least once every hour from 2000 until 0200, weather permitting, for 15 min and over a 14‐day period for each site. The UAS flew directly above (~4 m) and then descended (~4 m/s) within 1m of loafing gulls. No gulls interacted with the UAS and most flushed within 6 minutes. Generally, the first treatment of a night dispersed all gulls (min–max = 1–130 individuals) from the target roof for an extended period. Our operations were often grounded because of weather and our gull response data were limited because of few individuals present. We discuss our observations with particular attention to feasibility and possible implications such as shifting birds to other sites which, potentially, could be counterproductive for management

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

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

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