sequence in their devices combined: (1) the alarm call of the jay Garrulus glandarius; (2) the sound of a frightened brown hare Lepus europaeus; (3) a dog Canis
familiaris growling and barking; (4) a wolf Canis lupus howling; (5) squeal of a
wild boar Sus scrofa; and (6) warning sounds of roe deer Capreolus capreolus
(Babińska-Werka et al. 2015). These natural warning calls should promote the
alerted behavior of wild animals thus increasing their escape time from oncoming
trains. The sound warning devices may be placed along critical railway stretches
(e.g., in Babińska-Werka et al. 2015 they were separated by 70 m), being activated
by a signal sent by the automatic railway system in advance of a train (30 s to
3 min). The use of sound signalling increased the proportion of wildlife escaping
from the tracks, with individuals reacting faster and showing no evidence of
habituation to the warning signals (Babińska-Werka et al. 2015). Multiple horn
blasts have been used by train drivers to effectively flush animals (mostly ungulates) from rails (Helldin et al. 2011).
Physical barriers such as trees, diversion poles, flight diverters, or noise barriers, may contribute to the reduction of mortality, especially among birds (Bard
et al. 2002; Jacobson 2005; Kociolek et al. 2015; Zuberogoitia et al. 2015) and bats
(Ward et al. 2015). Pole barriers may represent a relatively inexpensive mitigation
measure, as they can be effective in diverting the flight of medium- or large-sized
birds above the poles (Zuberogoitia et al. 2015). The pole barriers used by
Zuberogoitia et al. (2015) consisted of: (1) gray PVC poles 2 m high and 8 cm wide
regularly separated by 1 or 2 m, and some had shredded pieces of coloured paper
(white or orange) attached to the top of the pole, or (ii) tree trunks (20–26 cm
diameter and 350 cm height) separated by 1 m.
Trees and other hedgerow vegetation can work as a barrier, preventing access to
railways, especially to large animals, and forcing birds and bats to fly above the
trains. However, this habitat can also become a refuge or foraging site for some
species (e.g., small birds and mammals), thus potentially working as an ecological
trap by attracting wildlife to the proximity of the railway.
Lighting and reflectors have been mainly tested on roads as wildlife deterrents.
This mitigation measure is used mostly for nocturnal species, and may reflect the
lights of vehicles or, alternatively, flash signals before an oncoming train. Lights
and reflectors may be combined with sound signalling to provide a faster response.
Nevertheless, lights should not be too intense in order to avoid blinding the animals,
whose reaction will probably be to stay still, thus remaining on the tracks.
Habitat and Wildlife Population Management
Lower numbers of wildlife species near railways can be achieved by controlling
populations (e.g., selective hunting, trapping), or by habitat modification. Changes
in habitat structure along railway verges may also increase animals’ capability to
detect and evade the train.
3 Methods to Monitor and Mitigate Wildlife Mortality in Railways
35
familiaris growling and barking; (4) a wolf Canis lupus howling; (5) squeal of a
wild boar Sus scrofa; and (6) warning sounds of roe deer Capreolus capreolus
(Babińska-Werka et al. 2015). These natural warning calls should promote the
alerted behavior of wild animals thus increasing their escape time from oncoming
trains. The sound warning devices may be placed along critical railway stretches
(e.g., in Babińska-Werka et al. 2015 they were separated by 70 m), being activated
by a signal sent by the automatic railway system in advance of a train (30 s to
3 min). The use of sound signalling increased the proportion of wildlife escaping
from the tracks, with individuals reacting faster and showing no evidence of
habituation to the warning signals (Babińska-Werka et al. 2015). Multiple horn
blasts have been used by train drivers to effectively flush animals (mostly ungulates) from rails (Helldin et al. 2011).
Physical barriers such as trees, diversion poles, flight diverters, or noise barriers, may contribute to the reduction of mortality, especially among birds (Bard
et al. 2002; Jacobson 2005; Kociolek et al. 2015; Zuberogoitia et al. 2015) and bats
(Ward et al. 2015). Pole barriers may represent a relatively inexpensive mitigation
measure, as they can be effective in diverting the flight of medium- or large-sized
birds above the poles (Zuberogoitia et al. 2015). The pole barriers used by
Zuberogoitia et al. (2015) consisted of: (1) gray PVC poles 2 m high and 8 cm wide
regularly separated by 1 or 2 m, and some had shredded pieces of coloured paper
(white or orange) attached to the top of the pole, or (ii) tree trunks (20–26 cm
diameter and 350 cm height) separated by 1 m.
Trees and other hedgerow vegetation can work as a barrier, preventing access to
railways, especially to large animals, and forcing birds and bats to fly above the
trains. However, this habitat can also become a refuge or foraging site for some
species (e.g., small birds and mammals), thus potentially working as an ecological
trap by attracting wildlife to the proximity of the railway.
Lighting and reflectors have been mainly tested on roads as wildlife deterrents.
This mitigation measure is used mostly for nocturnal species, and may reflect the
lights of vehicles or, alternatively, flash signals before an oncoming train. Lights
and reflectors may be combined with sound signalling to provide a faster response.
Nevertheless, lights should not be too intense in order to avoid blinding the animals,
whose reaction will probably be to stay still, thus remaining on the tracks.
Habitat and Wildlife Population Management
Lower numbers of wildlife species near railways can be achieved by controlling
populations (e.g., selective hunting, trapping), or by habitat modification. Changes
in habitat structure along railway verges may also increase animals’ capability to
detect and evade the train.
3 Methods to Monitor and Mitigate Wildlife Mortality in Railways
35