Wildlife in Airport Environments: Chapter 9 Managing Airport Stormwater to Reduce Attraction to Wildlife

An airport is a component of the landscape, contributing to and subject to local- and landscapelevel factors that affect wildlife populations and the hazards that these species pose to aviation (Blackwell et al. 2009, Martin et al. 2011). Water resources at and near an airport, in the form of both surface water and contained runoff, are recognized by the Federal Aviation Administration (FAA) as potential attractants to wildlife that pose hazards to aviation safety (FAA 2007). Surface water, including aboveground stormwater detention/retention facilities (see U.S. Environmental Protection Agency 2006), can represent a substantial proportion of the area within siting criteria for U.S. airports. An analysis of water coverage at 49 certificated airports (FAA 2004) revealed that surface water composed on average 6.0% (standard deviation [SD] = 10.4%, range = 0.04-48.3%; B. F. Blackwell, unpublished data) of the area within the 3-km [lo9-mile] FAA siting criteria (X = 275 ha, SD = 511 ha). A recent analysis of bird-aircraft strike data for avian species involved in at least 50 total strikes reported to the FAA (1990-2008; summarized in FAA 2011) revealed that 13 of the 52 species (25%) have foraging and breeding ecologies primarily associated with water (Blackwell et al. 2013). Moreover, these 13 species were responsible for \u3e 51% of damaging strikes (Dolbeer et al. 2000, DeVault et al. 2011) during this period

Frontal vehicle illumination via rear-facing lighting reduces potential for collisions with white-tailed deer

nimal–vehicle collisions cause many millions of animal deaths each year worldwide and present a substantial safety risk to people. In the United States and Canada, deer (Odocoileus spp.) are involved in most animal–vehicle collisions associated with human injuries. We evaluated a vehicle-based collision mitigation method designed to decrease the likelihood of deer–vehicle collisions during low-light conditions, when most collisions occur. Specifically, we investigated whether the use of a rear-facing light, providing more complete frontal vehicle illumination than standard headlights alone, enhanced vehicle avoidance behaviors of white-tailed deer (O. virginianus). We quantified flight initiation distance (FID), the likelihood of a dangerous deer–vehicle interaction (FID ≤ 50 m), and road-crossing behavior of deer in response to an oncoming vehicle using only standard high-beam headlights and the same vehicle using headlights plus an LED light bar illuminating the frontal surface of the vehicle. We predicted that frontal vehicle illumination would enhance perceived risk of deer approached by the vehicle and lead to more effective avoidance responses. We conducted 62 vehicle approaches (31 per lighting treatment) toward free-ranging deer over ~14 months. Although FID did not differ across treatments, the likelihood of a dangerous deer–vehicle interaction decreased from 35% of vehicle approaches using only headlights to 10% of vehicle approaches using the light bar. The reduction in dangerous interactions appeared to be driven by fewer instances of immobility (freezing) behavior by deer in response to the illuminated vehicle (n = 1) compared with approaches using only headlights (n = 10). Because more deer moved in response to the illuminated vehicle, road-crossing behavior likewise increased when the light bar was on, although these road crossings primarily occurred at FIDs \u3e 50 m and thus did not increase collision risk. Road-crossing behavior was influenced heavily by proximity to concealing cover; deer only crossed when the nearest cover was located on the opposite side of the road. We contend that frontal vehicle illumination via rearfacing lighting has potential to greatly reduce vehicle collisions with deer and other species. Future work should explore fine-tuning the method with regard to the visual capabilities of target species

Brown-Headed Cowbird (\u3cem\u3eMolothrus ater\u3c/em\u3e) Response to Pyrotechnics and Lethal Removal in a Controlled Setting

Pyrotechnics have long been used to frighten birds from specific areas but birds might habituate to them. Anecdotal and limited published reports suggest that killing a flock member can reduce habituation. However, little behavioral work has been conducted in this area. We exposed brown-headed cowbirds (Molothrus ater) to noise from either 0.22 caliber blanks or 15-mm pyrotechnics in a series of controlled, cage experiments to determine if killing a flock member increased the time that cowbirds respond to pyrotechnics. Cowbirds responded no differently to pyrotechnics following the death of a flock member either before or after habituation to pyrotechnics. Our results might have been influenced by cage effects or perceived inconsequence of the death of a conspecific. Further work with other species is warranted, particularly with regard to sociality

Identification of Off Airport Interspecific Avian Hazards to Aircraft

Understanding relative hazards of wildlife to aircraft is important for developing effective management programs that can minimize hazards from wildlife strikes. Although interspecific differences in hazard level of birds and mammals on airport properties are described, no studies have quantified hazard level of bird species or identified factors that influence hazard level when birds are struck beyond airport boundaries (e.g., during aircraft climb or approach). We used Federal Aviation Administration National Wildlife Strike Database records from 1990 through 31 May 2014 to identify bird species involved most often in collisions with aircraft beyond airport boundaries in the United States and to quantify the interspecific hazard level of those birds. We also investigated whether body mass, group size (single or multiple birds), region (Flyway), and season influenced the likelihood of aircraft damage and substantial damage when strikes occurred using binary logistic regression analysis. Canada geese (Branta canadensis; n=327), turkey vultures (Cathartes aura; 217), American robins (Turdus migratorius; 119), and mallards (Anas platyrhynchos; 107) were struck most often by aircraft beyond airport boundaries. Waterbirds (cormorants, ducks, geese, and to a lesser extent, gulls) and raptors (including vultures) were most likely to cause damage or substantial damage to aircraft when strikes occurred. Body mass was an important predictor of hazard level; group size, region, and season had lesser effects on hazard level. Management strategies to reduce bird strikes with aircraft beyond airport properties should be active throughout the year and prioritize waterbirds and raptors. Published 2016. This article is a U.S. Government work and is in the public domain in the USA

Identification of Off Airport Interspecific Avian Hazards to Aircraft

Understanding relative hazards of wildlife to aircraft is important for developing effective management programs that can minimize hazards from wildlife strikes. Although interspecific differences in hazard level of birds and mammals on airport properties are described, no studies have quantified hazard level of bird species or identified factors that influence hazard level when birds are struck beyond airport boundaries (e.g., during aircraft climb or approach). We used Federal Aviation Administration National Wildlife Strike Database records from 1990 through 31 May 2014 to identify bird species involved most often in collisions with aircraft beyond airport boundaries in the United States and to quantify the interspecific hazard level of those birds. We also investigated whether body mass, group size (single or multiple birds), region (Flyway), and season influenced the likelihood of aircraft damage and substantial damage when strikes occurred using binary logistic regression analysis. Canada geese (Branta canadensis; n=327), turkey vultures (Cathartes aura; 217), American robins (Turdus migratorius; 119), and mallards (Anas platyrhynchos; 107) were struck most often by aircraft beyond airport boundaries. Waterbirds (cormorants, ducks, geese, and to a lesser extent, gulls) and raptors (including vultures) were most likely to cause damage or substantial damage to aircraft when strikes occurred. Body mass was an important predictor of hazard level; group size, region, and season had lesser effects on hazard level. Management strategies to reduce bird strikes with aircraft beyond airport properties should be active throughout the year and prioritize waterbirds and raptors. Published 2016. This article is a U.S. Government work and is in the public domain in the USA

Far Infrared Prperties of M Dwarfs

We report the mid- and far-infrared properties of nearby M dwarfs. Spitzer/MIPS measurements were obtained for a sample of 62 stars at 24 um, with subsamples of 41 and 20 stars observed at 70 um and 160 um respectively. We compare the results with current models of M star photospheres and look for indications of circumstellar dust in the form of significant deviations of K-[24 um] colors and 70 um / 24 um flux ratios from the average M star values. At 24 um, all 62 of the targets were detected; 70 um detections were achieved for 20 targets in the subsample observed; and no detections were seen in the 160 um subsample. No clear far-infrared excesses were detected in our sample. The average far infrared excess relative to the photospheric emission of the M stars is at least four times smaller than the similar average for a sample of solar-type stars. However, this limit allows the average fractional infrared luminosity in the M-star sample to be similar to that for more massive stars. We have also set low limits for the maximum mass of dust possible around our stars.Comment: 28 pages, 4 figures, to be published in The Astrophysical Journa

Species With Greater Aerial Maneuverability Have Higher Frequency of Collisions With Aircraft: A Comparative Study

Antipredator responses may appear unsuccessful when animals are exposed to approaching vehicles, often resulting inmortality. Recent studies have addressed whether certain biological traits are associated with variation in collision risk with cars, but not with higher speed-vehicles like aircraft. Our goal was to establish the association between different species traits (i.e., body mass, eye size, brain size, wing loading, wing aspect ratio) and the frequency of bird collisions with aircraft (hereafter, bird strikes) using a comparative approach controlling for the effects of shared ancestry. We proposed directional predictions as to how each of the species traits would affect the frequency of bird strikes. Considering 39 bird species with all traits represented, the model containing wing loading had the best fit to account for the variance in bird strikes across species. In another model with 54 species exploring the fit to different polynomial models but considering only wing loading, we found that wing loading was negatively and linearly associated with the frequency of bird strikes. Counterintuitively, species with lower wing loading (hence, greater maneuverability) had a higher frequency of bird strikes. We discuss potential non-mutually exclusive explanations (e.g., high wing loading species fly faster, thus gaining some extra time to avoid the aircraft flight path; high wing loading species are hazed more intensively at airports, which could lower collisions, etc.). Ultimately, our findings uncovered that species with low wing loading get struck at a higher rate at airports, which reduces the safety risk for humans because these species tend not to cause damaging strikes, but the ecological consequences of their potentially higher local mortality are unknown

Deciphering interactions between white-tailed deer and approaching vehicle

Deer-vehicle collisions are a major transportation hazard, but factors affecting deer escape decision-making in response to vehicle approach remain poorly characterized. We made opportunistic observations of deer response to vehicle approach during daylight hours on a restricted- access facility in Ohio, USA (vehicle speeds were ≤64 km/h). We hypothesized that animal proximity to the road, group size, vehicle approach, and ambient conditions would affect perceived risk by white-tailed deer (Odocoileus virginianus) to vehicle approach, as measured by flight-initiation distance (FID). We constructed a priori models for FID, as well as road-crossing behavior. Deer responses were variable and did not demonstrate spatial or temporal margins of safety. Road-crossing behavior was slightly and positively influenced by group size during winter. Deer showed greater FIDs and likelihood of crossing when approached in the road; directionality of approach likely increased the perceived risk. These findings are consistent with antipredator theory relative to predator approach direction

Effects of visual obstruction, prey resources, and satiety on bird use of simulated airport grasslands

Grasslands represent 39%–50% of U.S. airport properties, and a recent management framework recommended exploiting both antipredator behaviours and food resources in airport grasslands to curb use by birds considered hazardous to aviation safety. We evaluated framework predictions empirically by exposing unsated and sated brown-headed cowbirds (Molothrus ater) to visually obstructive (∼13-cm vegetation height; tall), higher-risk plots versus unobstructive (height; short) plots, and relative to prey resources. We predicted that 1) unsated birds (unfed since the previous day) would be present in greater numbers and forage more in short than tall vegetation plots 24 h post-mowing because of invertebrate flush resulting from mowing; 2) unsated birds would show increasing numbers and foraging in tall plots \u3e24 h post-mowing because of decreasing food abundance and availability in short plots; and 3) sated birds would be present in greater numbers and forage more in short vegetation overall, because vigilance needs would exceed that of food needs. We evaluated effects of visual obstruction (a metric correlated with both vegetation height and insect density) on behaviours within plots via generalized linear mixed models. Unsated cowbirds showed nearly equal numbers in tall and short plots (X [SE] individuals using tall plots: 9.5 [5.1]; short plots: 9.8 [5.1], P = 1.00, Wilcoxon Signed Ranks Test), and foraged nearly equally in both plots 24 h post-mowing (tall plots: 6.9 [4.7] individuals; short plots: 6.6 [4.1] individuals, P = 0.94). Prey availability was likely enhanced within short plots within 24 h of mowing, but possibly in adjacent tall plots as well. Over the course of the experiments (8–9 days) unsated cowbirds showed no difference in numbers between plots (tall plots: 8.2 [4.9] individuals; short plots: 11.4 [4.9] individuals, P = 0.13), but foraged more in short plots (tall plots: 4.4 [3.8] individuals; short plots: 7.8 [4.2] individuals, P = 0.01); visual obstruction was significantly and negatively correlated with foraging in tall plots. Sated cowbirds selected for short plots (use of tall plots: 5.9 [4.2] individuals; short plots: 11.7 [4.6] individuals, P \u3c 0.01; foraging in tall plots: 4.1 [3.3] individuals; short plots: 8.2 [4.6] individuals, P \u3c 0.01). Our findings support recommendations for use of visually obstructive vegetation in combination with proactive control of food resources to reduce use of airport grasslands by birds that select against visually obstructive cover

Speed Kills: Effects of Vehicle Speed on Avian Escape Behavior

The avoidance of vehicles is a common challenge for birds in the modern world. Birds generally rely on antipredator behaviors to avoid vehicles, but modern vehicles are faster than predators. We predicted that birds may be unable to accurately estimate the speed of approaching vehicles, which could contribute to miscalculations in avoidance behaviors and cause collisions. We tested our prediction in two studies. In the first (DeVault et al. 2014), we baited turkey vultures (Cathartes aura) to roads with animal carcasses and measured flight initiation distance (FID) when driving a truck towards them at 30, 60, or 90 km/h. Despite a wide range of responses, FID of vultures increased by a factor of 1.85 as speed increased from 30 to 90 km/h. At 90 km/h there was no clear trend in FID across replicates; birds were equally likely to initiate escape behavior at 40 m as at 220 m. Seventeen percent of vehicle approaches at 90 km/h resulted in near collisions with vultures, compared to none during 60 km/h approaches and 4% during 30 km/h approaches. In the second experiment (DeVault et al. 2015), we used video playback to investigate escape behaviors of captive brown-headed cowbirds (Molothrus ater) in response to virtual vehicles appearing to approach at speeds ranging from 60-360 km/h. Flight initiation distance remained similar across vehicle speeds, indicating that avoidance behaviors in cowbirds were based on distance rather than time available for escape. Cowbirds generally did not initiate flight with enough time to avoid “collision” when virtual vehicle speed exceeded 120 km/h. Although potentially effective for escaping predators, the decision-making processes used by turkey vultures and cowbirds in our experiments appear maladaptive in the context of avoiding vehicles, and may represent important determinants of bird-vehicle collisions