Integrating mammalian hazards with management at U.S. civil airports: a case study

Wildlife incidents with U.S. civil aircraft cost an estimated $1.4 billion from 1990 to 2010, with mammals 5 times more likely to cause damage than other wildlife. We surveyed 2 general aviation (GA) airports and 6 Part-139 certificated (i.e., certified) airports to assess efficacy of management practices for mammalian species hazardous to aircraft. We obtained information on mammalian species present on airport grounds, types and estimated effectiveness of management techniques, and effort spent on wildlife management. We evaluated management techniques relative to aircraft–wildlife collisions (i.e., incident) frequencies taken from Federal Aviation Administration’s (FAA) National Wildlife Strike Database and species hazard scores calculated by body mass. Certificated airports spent 5 times more effort and used twice as many techniques as GA airports. Species considered most hazardous by all airports included white-tailed deer (Odocoileus virginianus; hazard score = 94) and coyote (Canis latrans; 62). Generally, all airports surveyed are managing effectively for mammals; however, we recommend that airports with deer present install additional exclusion devices. By prioritizing species to manage and targeting management for them, airports can reduce mammalian risks to U.S. civil aircraft

White-Tailed Deer Incidents With U.S. Civil Aircraft

Aircraft incidents with ungulates cause substantial economic losses and pose risks to human safety. We analyzed 879 white-tailed deer (Odocoileus virginianus) incidents with United States civil aircraft from 1990 to 2009 reported in the Federal Aviation Administration National Wildlife Strike Database. During that time, deer incidents followed a quadratic response curve, peaking in 1994 and declining thereafter. There appeared to be some seasonal patterning in incident frequency, with deer incidents increasing overall from January to November, and peaking in October and November (30.7%). Most incidents (64.8%) occurred at night, but incident rates were greatest (P 0.001) at dusk. Landing-roll represented 60.7% of incidents and more incidents occurred during landing than take-off (P 0.001). Almost 70% of deer incidents had an effect on flight. About 6% of pilots attempted to avoid deer, and were less likely to sustain damage. Aircraft were 25 times more likely to be destroyed when multiple deer were struck versus a single individual. Deer incidents represented 0.9% of all wildlife incidents, yet 5.4% of total estimated costs. Reported costs for deer incident damages during this period exceeded US$36 million, with US$75 million in total estimated damages. Deer incidents resulted in 1 of 24 human deaths and 26 of 217 injuries reported for all wildlife incidents with aircraft during the reporting period. Managers should implement exclusion techniques (e.g., fences, cattle guards, or electrified mats) to maximize reductions in deer use of airfields. Where exclusion is not practical, managers should consider lethal control, habitat modifications, increased monitoring and hazing, and improved technology to aircraft and runway lighting to reduce incidents at airports

Theory of sound attenuation in glasses: The role of thermal vibrations

Sound attenuation and internal friction coefficients are calculated for a realistic model of amorphous silicon. It is found that, contrary to previous views, thermal vibrations can induce sound attenuation at ultrasonic and hypersonic frequencies that is of the same order or even larger than in crystals. The reason is the internal-strain induced anomalously large Gr\"uneisen parameters of the low-frequency resonant modes.Comment: 8 pages, 3 figures; to appear in PR

Carrion Availability in Space and Time

Introduction Availability of carrion to scavengers is a central issue in carrion ecology and management, and is crucial for understanding the evolution of scavenging behaviour. Compared to live animals, their carcasses are relatively unpredictable in space and time in natural conditions, with a few exceptions (see below, especially Sect. “Carrion Exchange at the Terrestrial-Aquatic Interface”). Carrion is also an ephemeral food resource due to the action of a plethora of consumers, from microorganisms to large vertebrates, as well as to desiccation (i.e., loss of water content; DeVault et al. 2003; Beasley et al. 2012; Barton et al. 2013; Moleón et al. 2014). With a focus on vertebrate carcasses, here we give an overview of (a) the causes that produce carrion, (b) the rate of carrion production, (c) the factors affecting carrion quality, and (d) the distribution of carrion in space and time, both in terrestrial and aquatic environments (including their interface). In this chapter, we will focus on naturally produced carrion, whereas non-natural causes of animal mortality are described in chapter “Human-Mediated Carrion: Effects on Ecological Processes”. However, throughout this chapter we also refer to extensive livestock carrion, because in the absence of strong restrictions such as those imposed in the European Community after the bovine spongiform encephalopathy crisis (Donázar et al. 2009; Margalida et al. 2010), the spatiotemporal availability of carrion of extensive livestock and wild ungulates is similar

Mitigation of Double-crested Cormorant Impacts on Lake Ontario: From Planning and Practice to Product Delivery

The New York State Department of Environmental Conservation initiated a Double-crested Cormorant (Phalacrocorax auritus) control program in the eastern basin of Lake Ontario to mitigate cormorant impacts in 1999. Key objectives included improving the quality of Smallmouth Bass (Micropterus dolomieu) and other fisheries, restoring the structure and function of the warmwater fish community and reducing cormorant impacts to nesting habitats of other colonial waterbird species. In eight years of intensive control, cormorant numbers declined, with a corresponding reduction in estimated fish consumption. Diversity and numbers of co-occurring waterbirds either increased or have not been shown to be negatively impacted by management. Woody vegetation favorable to Black-crowned Night-Herons (Nycticorax nycticorax) has been maintained. A ca. 2.5-fold increase in the abundance of Smallmouth Bass abundance in assessment nets over the last seven years is a sign of improved recruitment to the fishery. Since the target population level of 4,500 to 6,000 cormorants has essentially been achieved, the eastern Lake Ontario cormorant program is expected to shift in 2007 from a population reduction focus towards a less intensive program intended to prevent population resurgence

Mitigation of Double-crested Cormorant Impacts on Lake Ontario: From Planning and Practice to Product Delivery

The New York State Department of Environmental Conservation initiated a Double-crested Cormorant (Phalacrocorax auritus) control program in the eastern basin of Lake Ontario to mitigate cormorant impacts in 1999. Key objectives included improving the quality of Smallmouth Bass (Micropterus dolomieu) and other fisheries, restoring the structure and function of the warmwater fish community and reducing cormorant impacts to nesting habitats of other colonial waterbird species. In eight years of intensive control, cormorant numbers declined, with a corresponding reduction in estimated fish consumption. Diversity and numbers of co-occurring waterbirds either increased or have not been shown to be negatively impacted by management. Woody vegetation favorable to Black-crowned Night-Herons (Nycticorax nycticorax) has been maintained. A ca. 2.5-fold increase in the abundance of Smallmouth Bass abundance in assessment nets over the last seven years is a sign of improved recruitment to the fishery. Since the target population level of 4,500 to 6,000 cormorants has essentially been achieved, the eastern Lake Ontario cormorant program is expected to shift in 2007 from a population reduction focus towards a less intensive program intended to prevent population resurgence

Can experience reduce collisions between birds and vehicles?

Bird collisions with vehicles cause serious safety, financial and conservation concerns worldwide, but the causes of such collisions are poorly described. We investigated how experience with vehicles influenced avian avoidance responses. We trained three groups of vehicle-naiıve rock pigeons Columba livia with 32 near-miss vehicle approaches over 4 weeks at 60 and 120 km h-1, and also included individuals that heard but did not see the approaches (control group). We subsequently measured flight initiation distance (FID) and whether individuals ‘collided’ with a virtual vehicle directly approaching at 120 or 240 km h-1 using video playback. We found that inexperienced individuals (i.e. the control group) had longer FIDs than experienced birds, although only one of 90 individuals across groups successfully avoided virtual collision. Vehicle approach speed during video playback and the interaction of approach speed and training group did not influence FID. Our results suggest that a habituation-like effect based on repeated observations of passing vehicles could contribute to ineffective vehicle avoidance responses by birds when collisions are imminent. Novel strategies should be developed to enhance avoidance responses to high-speed vehicles to minimize bird mortality

Modeling the cost of bird strikes to US civil aircraft

The objective of our analysis is to develop a model of damage costs that arise from collisions between aircraft and birds, based on data drawn from the Federal Aviation Administration National Wildlife Strike Database (NWSD). We develop a two-part model, composed of two separate statistical models, that accounts for the effects of aircraft mass category, engine type, component of the aircraft struck, and the size and number of birds struck. Our results indicate the size of bird, number of birds, and engine ingestions are the largest determinants of strike-related costs. More generally, our result is a model that provides a better understanding of the determinants of damage costs and that can be used to interpolate the substantial amount of missing data on damage costs that currently exists within the NWSD. A more complete accounting of damage costs will allow a better understanding of how damage costs vary geographically and temporally and, thus, enable more efficient allocation of management resources across airports and seasons

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

Landscape transformations produce favorable roosting conditions for turkey vultures and black vultures

Recent increases in turkey vulture (Cathartes aura) and black vulture (Coragyps atratus) populations in North America have been attributed in part to their success adapting to human-modified landscapes. However, the capacity for such landscapes to generate favorable roosting conditions for these species has not been thoroughly investigated. We assessed the role of anthropogenic and natural landscape elements on roosting habitat selection of 11 black and 7 turkey vultures in coastal South Carolina, USA using a GPS satellite transmitter dataset derived from previous research. Our dataset spanned 2006–2012 and contained data from 7916 nights of roosting. Landscape fragmentation, as measured by land cover richness, influenced roosting probability for both species in all seasons, showing either a positive relationship or peaking at intermediate values. Roosting probability of turkey vultures was maximized at intermediate road densities in three of four seasons, and black vultures showed a positive relationship with roads in fall, but no relationship throughout the rest of the year. Roosting probability of both species declined with increasing high density urban cover throughout most of the year. We suggest that landscape transformations lead to favorable roosting conditions for turkey vultures and black vultures, which has likely contributed to their recent proliferations across much of the Western Hemisphere