In Spain, 18.4% of mammal casualties from trains were carnivores (excluding
domestic species), mainly fox and stone marten (Martes foina). Ungulates (mostly
wild boar) and lagomorphs were also frequently killed by trains, 14.4% each (SCV
1996). Bats may be also killed by trains, especially on railway tunnels and sections
close to old buildings, but no data are available to document this for railways (SCV
1996). Information for roads indicates that bats are very difficult to detect (Santos
et al. 2011). Thus, bat mortality on railways can be high but have been ignored.
In general, most reported mammal victims are common species, which suggests
that the effects on population levels should be small for species with large and
widespread populations (van der Grift and Kuijsters 1998). However, the death of a
few individuals of a rare or endangered species may further increase species
extinction risk (van der Grift 1999).
Bird Mortality
From the assessment of bird carcasses found on railway tracks, it has been frequently deduced from monitoring studies that the cause of mortality was due to
collisions (Peña and Llama 1997), although collisions with the catenary, electrocution and barotrauma induced by the train movement are also possible bird
mortality causes related to the railways (SCV 1996).
The frequency of bird mortality by trains when compared to other taxonomic
groups varies from 11% (USA), to 55% (Spain) and 57% (Netherlands) (Heske
2015; SCV 1996; van der Grift and Kuijsters 1998). In Chicago state, USA, most
frequent victims were mallard duck (Anas platyrhynchos), common grackle
(Quicalus quiscula) and sora (Porzana carolina), while songbirds were infrequent
(Heske 2015). In the Netherlands, accidents concerned mostly swans (Cygnus spp.),
ducks (family Anatidae) and coots (Fulica spp.). Gulls (family Laridae) and raptors
such as hawks and owls were also reported frequently (van der Grift and Kuijsters
1998). In Guadarrama (Spain), Peña and Llama (1997) monitored for two years the
bird mortality in 8 km of railways. The tawny owl (Strix aluco) was the most
frequent bird victim (18%), followed by the carrion crow (Corvus corone; 16%)
and the little owl (Athene noctua; 9.6%). Nearly half (46.8%) of this mortality
occurred in the summer, while much lower values (13.8 and 16%) occurred in the
winter and spring, respectively. Another report for Spanish railways (SCV 1996)
also found that owls were the most common victims (22.5% of all birds). Barn owl
(Tyto alba), tawny owl and little owl were the main victims, although there were
also records of eagle owl (Bubo bubo), long-eared owl (Asio otus) and scops owl
(Otus scops). As in road-related night mortality, train lights are likely responsible
for the majority of owl kills. It was observed that little owls when perched on the
train catenary, became disoriented with the approaching train, hence increasing the
likelihood of being killed (Peña and Llama 1997; SCV 1996).
Birds of prey were also frequently registered as train casualties in Spanish
railways being 19.2% of all birds killed (SCV 1996). The most recorded species
16
S.M. Santos et al.
domestic species), mainly fox and stone marten (Martes foina). Ungulates (mostly
wild boar) and lagomorphs were also frequently killed by trains, 14.4% each (SCV
1996). Bats may be also killed by trains, especially on railway tunnels and sections
close to old buildings, but no data are available to document this for railways (SCV
1996). Information for roads indicates that bats are very difficult to detect (Santos
et al. 2011). Thus, bat mortality on railways can be high but have been ignored.
In general, most reported mammal victims are common species, which suggests
that the effects on population levels should be small for species with large and
widespread populations (van der Grift and Kuijsters 1998). However, the death of a
few individuals of a rare or endangered species may further increase species
extinction risk (van der Grift 1999).
Bird Mortality
From the assessment of bird carcasses found on railway tracks, it has been frequently deduced from monitoring studies that the cause of mortality was due to
collisions (Peña and Llama 1997), although collisions with the catenary, electrocution and barotrauma induced by the train movement are also possible bird
mortality causes related to the railways (SCV 1996).
The frequency of bird mortality by trains when compared to other taxonomic
groups varies from 11% (USA), to 55% (Spain) and 57% (Netherlands) (Heske
2015; SCV 1996; van der Grift and Kuijsters 1998). In Chicago state, USA, most
frequent victims were mallard duck (Anas platyrhynchos), common grackle
(Quicalus quiscula) and sora (Porzana carolina), while songbirds were infrequent
(Heske 2015). In the Netherlands, accidents concerned mostly swans (Cygnus spp.),
ducks (family Anatidae) and coots (Fulica spp.). Gulls (family Laridae) and raptors
such as hawks and owls were also reported frequently (van der Grift and Kuijsters
1998). In Guadarrama (Spain), Peña and Llama (1997) monitored for two years the
bird mortality in 8 km of railways. The tawny owl (Strix aluco) was the most
frequent bird victim (18%), followed by the carrion crow (Corvus corone; 16%)
and the little owl (Athene noctua; 9.6%). Nearly half (46.8%) of this mortality
occurred in the summer, while much lower values (13.8 and 16%) occurred in the
winter and spring, respectively. Another report for Spanish railways (SCV 1996)
also found that owls were the most common victims (22.5% of all birds). Barn owl
(Tyto alba), tawny owl and little owl were the main victims, although there were
also records of eagle owl (Bubo bubo), long-eared owl (Asio otus) and scops owl
(Otus scops). As in road-related night mortality, train lights are likely responsible
for the majority of owl kills. It was observed that little owls when perched on the
train catenary, became disoriented with the approaching train, hence increasing the
likelihood of being killed (Peña and Llama 1997; SCV 1996).
Birds of prey were also frequently registered as train casualties in Spanish
railways being 19.2% of all birds killed (SCV 1996). The most recorded species
16
S.M. Santos et al.