Speed kills: ineffective avian escape responses to oncoming vehicles

Abstract

Animal-vehicle collisions cause high levels of vertebrate mortality worldwide, and what goes wrong when animals fail to escape and ultimately collide with vehicles is not well understood. We investigated alert and escape behaviours of captive brown-headed cowbirds (Molothrus ater) in response to virtual vehicle approaches of different sizes and at speeds ranging from 60 to 360 km h 21 . Alert and flight initiation distances remained similar across vehicle speeds, and accordingly, alert and flight initiation times decreased at higher vehicle speeds. Thus, avoidance behaviours in cowbirds appeared to be based on distance rather than time available for escape, particularly at 60-150 km h 21 ; however, at higher speeds (more than or equal to 180 km h 21 ) no trend in response behaviour was discernible. As vehicle speed increased, cowbirds did not have enough time to assess the approaching vehicle, and cowbirds generally did not initiate flight with enough time to avoid collision when vehicle speed exceeded 120 km h 21 . Although potentially effective for evading predators, the decision-making process used by cowbirds in our study appears maladaptive in the context of avoiding fast-moving vehicles. Our methodological approach and findings provide a framework to assess how novel management strategies could affect escape rules, and the sensory and cognitive abilities animals use to avoid vehicle collisions.

The Potential Effects of Forest Roads on the Environment and Mitigating their Impacts

“…This study used simulated vehicles similar to those used in human-vehicle interaction studies in order to not harm the birds. As expected, DeVault found as the vehicle's speed increased, the birds were increasingly unable to escape being harmed [15].…”

“…Hundreds of millions of birds are struck by vehicles annually [15]. DeVault [15] used brown-headed cowbirds (Molothrus ater) in an experiment to test the birds' responses to vehicles traveling at different speeds and with different sight distance between the birds and the vehicles. This study used simulated vehicles similar to those used in human-vehicle interaction studies in order to not harm the birds.…”

Effects of Road Density and Pattern on the Conservation of Species and Biodiversity

“…In fact, many of the research studies undertaken on road mortality tended to explore the differences between and within species with the intention of informing more targeted mitigation. For instance, studies considered in this review found that a variety of species-associated factors influenced the rate of wildlife-vehicle collisions, such as age (particularly dispersing juveniles; [19][20][21][22][23]), activity patterns (such as nocturnal and migratory activities; [6,7,24,25]), season (primarily breeding season; [12,[26][27][28][29]), gender (such as males ranging further in the breeding season in search a mate; [23,26,[30][31][32]), diet preferences (e.g., one study found that omnivorous mammals and herbivorous birds were most vulnerable; [33]), mobility (including low-flying species; [15,21,34,35]), behavioral responses (e.g., certain species do not respond to oncoming traffic; [15,36]), and home range size (i.e., the larger the home range the higher the probability of crossing a road; [37]). Another study found that species that were more inconspicuous on the roads were more vulnerable to wildlife-vehicle collisions [38].…”

On-Board Video Recording Unravels Bird Behavior and Mortality Produced by High-Speed Trains

“…Thus, it misses birds that react early and escape upon commencement of ground and catenary vibration, which occurs 5-10 s before train arrival (personal observation). The delayed reaction is in accordance with the limited capacity of the birds to react to objects approaching at high speed (Martin, 2011;DeVault et al, 2015), and depicts the reduced probability of wildlife to escape from an approaching high-speed train.…”

“…Also, (ii) efforts should be aimed at reducing the attractiveness of rail surroundings to birds, not only structural elements (poles, catenary), but also the habitat of the embankments (Malo et al, 2017), as well as reducing the potential of dense populations of prey in embankments that can attract birds (Planillo et al, 2015). Unfortunately, addressing the small escape distance for the birds may not be possible given the sensory and behavioral limitations of birds (Martin, 2011;DeVault et al, 2015).…”