Warning signals triggered by trains increase escape time for wildlife
Written By Jonathan Backs PhD
Departments of Chemical and Materials Engineering and Biological Sciences, University of Alberta
2nd December, 2020
Animals could avoid train collisions if warned
Wildlife are killed in collisions with trains wherever animals and railways exist together. Although a range of effective tools have been developed to reduce wildlife collisions on roads, few practical measures exist that can reduce collisions on railways. One key difference between these contexts is that heavy trains cannot slow safely or change course to avoid animals.
To help animals avoid trains, we designed a warning system that provides light-and-sound warning signals near the track during the 30 seconds leading up to train arrival. Because the warning signals are always followed by the close approach of a train, we expected that animals could learn to use the warning signals as a cue to leave the track.
We tested this concept by measuring the flight behaviour of wild, free-ranging animals on an active railway. We expected that animals would flee from trains earlier where we provided warning signals. We also compared animal responses where trains approached from straight versus curved sections of track, where trains might be more difficult to for animals see and hear.
Experimental test of our warning system
Our warning system is a network of electronic devices that can be attached to the railway track at a site targeted for collision reduction (Fig. 1). The rationale and design for this system is described in detail in a previous publication (Backs et al. 2017). The system detects trains as they approach the site and emits flashing lights and bell sounds 30 seconds before trains arrive at the target site.
Figure 1: Warning device activating as a train approaches. Image used with permission from CBC TV.
We tested our system at four sites along the Canadian Pacific Railway within Banff National Park, Alberta, Canada. Here, trains collide with and kill provincially threatened grizzly bears as well as other species of mammals and birds.
Warning signals were provided (treatment) or not (control) at two of the four sites each for periods of two to four weeks. We swapped the treatment and control conditions after each time period to control for seasonal effects over the nine-month experiment. We used trail cameras, activated before the warning signals and recording until the train passed, to observe the responses of animals to warnings and trains at each site. From these recordings, we looked for the first animal to flee and noted when its flight response began. The amount of time between the moment of flight and the arrival of the train at the flight location we termed the flight initiation time. This was the time that the animal used to escape the train.
For our analysis, we grouped large mammal species (hereafter, large animals) separately from smaller mammals and birds (hereafter, small animals).
Warnings increase escape time for animals
Figure 2: Effect of treatment on flight initiation time for four groupings of approach curvature and animal size. Box plots indicate medians, first and third quartiles, and range to 1.5 times the interquartile range. Means and standard errors are indicated by the filled circles with ranges. All data points are shown with test site indicated by shape and position grouping. Image reproduced from Backs et al. 2020.
We observed flight sequences for 25 large animals and 149 small animals (Fig. 2). Large animals left the track 62% (6.5 s) earlier where we provided warning signals (10.5 s control, 17.0 s treatment), giving them an extra 110 m of space to escape the approaching trains. Small animals left the track 29% (3.3 s) earlier (11.3 s control, 14.6 s treatment), equivalent to 55 m of extra space. For highly mobile species like grizzly bears, this increased margin of safety could reduce the risk of collisions.
Contrary to our expectation, animals were more responsive to warning signals when trains approached from straightaways. This suggests that warning signals may be more useful for animals when presented together with train stimuli.
Based on these findings, animal warning systems seem promising for use in the railway context. Railway companies could directly support more testing of warning systems to find out if the observed increase in escape time reduces the risk of wildlife collisions where warnings are deployed. Railways can also facilitate further research by keeping detailed records of wildlife collisions on their lines, including the direction of travel for trains involved in collisions, and by recording video footage of collisions.
Author information:
Jonathan Backs, PhD Departments of Chemical and Materials Engineering and Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
E-mail: jbacks@ualberta.ca
Source:
J.A.J. Backs, J.A. Nychka, C.C. St. Clair, 2017. Warning systems triggered by trains could reduce collisions with wildlife. Ecological Engineering, 106(A), 563–569. DOI: 10.1016/j.ecoleng.2017.06.024
J.A.J. Backs, J.A. Nychka, C.C. St. Clair, 2020. Warning systems triggered by trains increase flight-initiation times of wildlife. Transportation Research Part D: Transport and Environment, 87, 102502. DOI: 10.1016/j.trd.2020.102502
Editor:
Rodney van der Ree
Cite this summary:
Backs, J. 2020. Warning signals triggered by trains increase escape time for wildlife. Edited by van der Ree, R. TransportEcology.info, Accessed at: https://transportecology.info/research/warning-signals-trains [Date accessed].