were the buzzard (Buteo buteo), black kite (Milvus migrans) and griffon vulture
(Gyps fulvus). One possible explanation is the attractiveness of perches along the
trails and of railway verges as a hunting ground for birds of prey and owls (SCV
1996; van der Grift and Kuijsters 1998). Moreover, all three species scavenge
regularly the trails for food carcasses, increasing their vulnerability to collisions
(SCV 1996).
In some areas, train drivers observed several partridges (Alectoris rufa) using the
gravel from the track ballast or within the train track on rainy days, being thus killed
altogether (Peña and Llama 1997). This last behaviour of galliforme birds, seeking
refuge on the train tracks, has also been referred by Havlin (1987) for the common
pheasant (Phasianus colchicus).
As is often the case, for small or isolated populations the death of a few individuals represents a serious risk to population decline (van der Grift and Kuijsters
1998). In particular, birds of prey and owls are sensitive in this respect, even though
some species may be considered common. Railway traffic is the second cause of
mortality in the Netherlands for the buzzard and the kestrel (Falco tinnunculus),
with 7.1 and 4.6%, respectively, of all dead birds found (van der Grift and Kuijsters
1998 and references therein). For the barn owl, railway traffic is a genuine danger,
as 16% of mortality in Brittany (France) was caused by trains (SCV 1996). Also, for
the little owl, 3.6% of deaths result from train accidents (van der Grift and Kuijsters
1998 and references therein).
Concerning the mortality of protected birds, the Spanish train personnel referred
one fatal collision with one young imperial eagle (Aquila adalberti) in a rail section
close to the nest, and collisions with several black vultures (Aegypius monachus)
when feeding on carcasses on the rail (Peña and Llama 1997). Also, in the Swiss
Alps, the collisions with trains or cars were the third cause of mortality among eagle
owls, accounting for 30% of the anthropogenic mortality (Schaub et al. 2010).
Not all deaths in railways are caused by train collisions. Some of the mortality
arises from the collision with the rail electric lines. This has been clearly observed
in Spain for the buzzard, barn owl, eagle owl, lesser kestrel (Falco naumanni),
sparrowhawk (Accipiter nisus), song thrush (Turdus philomelos), and starlings
(Sturnus sp). But, still, the most frequent cause of death was train collisions (SCV
1996).
Amphibian and Reptile Mortality
As stated before, most railway studies focus only on the mortality of large species
(van der Grift 1999). In addition, reports on train-collisions often underestimate the
true number of collisions, as detectability and persistence rates of carcasses are
rarely estimated (see Chap. 3, and van der Grift 1999), problems that affect mainly
small body size species (SCV 1996). Thus, there is still an important difference
between the abundance of amphibian and reptile mortality in roads and in railways.
While there are plenty of data on mortality of these taxa on roads (Beebee 2013;
2 Current Knowledge on Wildlife Mortality in Railways
17
(Gyps fulvus). One possible explanation is the attractiveness of perches along the
trails and of railway verges as a hunting ground for birds of prey and owls (SCV
1996; van der Grift and Kuijsters 1998). Moreover, all three species scavenge
regularly the trails for food carcasses, increasing their vulnerability to collisions
(SCV 1996).
In some areas, train drivers observed several partridges (Alectoris rufa) using the
gravel from the track ballast or within the train track on rainy days, being thus killed
altogether (Peña and Llama 1997). This last behaviour of galliforme birds, seeking
refuge on the train tracks, has also been referred by Havlin (1987) for the common
pheasant (Phasianus colchicus).
As is often the case, for small or isolated populations the death of a few individuals represents a serious risk to population decline (van der Grift and Kuijsters
1998). In particular, birds of prey and owls are sensitive in this respect, even though
some species may be considered common. Railway traffic is the second cause of
mortality in the Netherlands for the buzzard and the kestrel (Falco tinnunculus),
with 7.1 and 4.6%, respectively, of all dead birds found (van der Grift and Kuijsters
1998 and references therein). For the barn owl, railway traffic is a genuine danger,
as 16% of mortality in Brittany (France) was caused by trains (SCV 1996). Also, for
the little owl, 3.6% of deaths result from train accidents (van der Grift and Kuijsters
1998 and references therein).
Concerning the mortality of protected birds, the Spanish train personnel referred
one fatal collision with one young imperial eagle (Aquila adalberti) in a rail section
close to the nest, and collisions with several black vultures (Aegypius monachus)
when feeding on carcasses on the rail (Peña and Llama 1997). Also, in the Swiss
Alps, the collisions with trains or cars were the third cause of mortality among eagle
owls, accounting for 30% of the anthropogenic mortality (Schaub et al. 2010).
Not all deaths in railways are caused by train collisions. Some of the mortality
arises from the collision with the rail electric lines. This has been clearly observed
in Spain for the buzzard, barn owl, eagle owl, lesser kestrel (Falco naumanni),
sparrowhawk (Accipiter nisus), song thrush (Turdus philomelos), and starlings
(Sturnus sp). But, still, the most frequent cause of death was train collisions (SCV
1996).
Amphibian and Reptile Mortality
As stated before, most railway studies focus only on the mortality of large species
(van der Grift 1999). In addition, reports on train-collisions often underestimate the
true number of collisions, as detectability and persistence rates of carcasses are
rarely estimated (see Chap. 3, and van der Grift 1999), problems that affect mainly
small body size species (SCV 1996). Thus, there is still an important difference
between the abundance of amphibian and reptile mortality in roads and in railways.
While there are plenty of data on mortality of these taxa on roads (Beebee 2013;
2 Current Knowledge on Wildlife Mortality in Railways
17