Social information affects Canada goose alert and escape responses to vehicle approach: implications for animal–vehicle collisions

Abstract

BackgroundAnimal–vehicle collisions represent substantial sources of mortality for a variety of taxa and can pose hazards to property and human health. But there is comparatively little information available on escape responses by free-ranging animals to vehicle approach versus predators/humans.MethodsWe examined responses (alert distance and flight-initiation distance) of focal Canada geese (Branta canadensis maxima) to vehicle approach (15.6 m·s−1) in a semi-natural setting and given full opportunity to escape. We manipulated the direction of the vehicle approach (direct versus tangential) and availability of social information about the vehicle approach (companion group visually exposed or not to the vehicle).ResultsWe found that both categorical factors interacted to affect alert and escape behaviors. Focal geese used mostly personal information to become alert to the vehicle under high risk scenarios (direct approach), but they combined personal and social information to become alert in low risk scenarios (tangential approach). Additionally, when social information was not available from the companion group, focal birds escaped at greater distances under direct compared to tangential approaches. However, when the companion group could see the vehicle approaching, focal birds escaped at similar distances irrespective of vehicle direction. Finally, geese showed a greater tendency to take flight when the vehicle approached directly, as opposed to a side step or walking away from the vehicle.ConclusionsWe suggest that the perception of risk to vehicle approach (likely versus unlikely collision) is weighted by the availability of social information in the group; a phenomenon not described before in the context of animal–vehicle interactions. Notably, when social information is available, the effects of heightened risk associated with a direct approach might be reduced, leading to the animal delaying the escape, which could ultimately increase the chances of a collision. Also, information on a priori escape distances required for surviving a vehicle approach (based on species behavior and vehicle approach speeds) can inform planning, such as location of designated cover or safe areas. Future studies should assess how information from vehicle approach flows within a flock, including aspects of vehicle speed and size, metrics that affect escape decision-making.

Can we use anti-predator behavior theory to predict wildlife responses to high-speed vehicles?

“…However, to apply these models a key is that animals respond similarly to vehicle approaches as predator approaches. This has been empirically corroborated in the context of both car approaches and aircraft approaches (Blackwell et al 2019b) [9][10][11][12][13]. Specifically, when animals are approached by vehicles, they become alert and later engage in escape behavior to avoid a collision [9,[14][15][16] .…”

“…To that end, we needed published data on the responses of animals to vehicles (rather than predators or humans) travelling at known speeds. Unfortunately, little empirical data were available to feed the different parameters each model requires relative to responses to vehicles [9,[14][15][16]. We chose to parameterize the different models with data from DeVault et al [15] because the study features the largest range of approach speeds to which an animal was exposed in a systematic and experimental manner.…”

“…Simulation studies have been used extensively in ecology and evolution, [55][56] particularly when empirical data are lacking, like in our case. We focused on birds, as they have a high representation in the literature of animal-vehicle collisions, [9,12,15,16] which facilitated obtaining empirical estimates for the different parameters.…”

Effects of a Wave Power Park with No-Take Zone on Decapod Abundance and Size

“…Model residuals were not normally distributed for the data of the decapod abundance caught with the small and large cages for all years combined or in the years 2018, 2019 for the data of decapod abundance caught with the large cages, despite attempts to log(1+x)-transform the response variable. However, linear and linear mixed effects models are quite robust to violation of assumptions regarding normality of model residuals [54][55][56].…”

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

“…Because high‐speed vehicles are evolutionarily novel, collisions often result from the use of maladaptive avoidance responses by animals, including antipredator behaviors used as surrogates for more appropriate but usually absent vehicle avoidance behaviors (Lima et al 2015, Blackwell et al 2016). For example, individual Canada geese ( Branta canadensis ) often run or fly ahead of a truck as if being chased by a predator, rather than move a short distance to the side, away from the vehicle’s projected path (Blackwell et al 2019). Likewise, loose flocks of Canada geese have been observed coalescing into tight groups when directly approached by an aircraft (Blackwell et al 2012).…”