Direct counts of mid- and large-sized birds were conducted by car, as is common
(Alonso et al. 2005; Morales et al. 2008). For these counts, the car was driven
slowly along dirt tracks up to 1000 m from the railway, with a fixed detection band
of 1000 m to each side of the vehicle. Regular stops were made to prospect the area
thoroughly, including the surroundings of the railway and control sites on both
sides. All morning, censuses were carried out within four hours of sunrise, and
afternoon censuses were done in the 2 h before sunset. Censuses were done on days
with good visibility and no rain, and hunting days were avoided.
In the landscape traversed by the HSR, the avian community was typical of that in
the (Traba et al. 2013). Outstanding species typical of steppes include the great bustard,
little bustard (Tetrax tetrax), and calandra lark (Melanocorypha calandra), together
with others common in agricultural areas, including the spotless starling (Sturnus
unicolor), rock dove (Columba livia), common magpie (Pica pica), sparrows (Passer
spp., Petronia petronia), and several Fringilidae and Embericidae species.
In all, 80 bird species have been detected in the study area, reflecting the
presence of a rich bird community, though 40–50% of the species that have been
observed in the area were detected in fewer than 10 observations within each
sampling period. Eleven species of high conservation interest were present in the
area, including the black kite (Milvus milvus), which is nationally classified as
“endangered” (Madroño et al. 2004). Species classified as “vulnerable” that were
observed in the area include the great bustard, pin-tailed sandgrouse (Pterocles
alchata), black-bellied sandgrouse (P. orientalis) and little bustard as well as
Montagu’s harrier (Circus pygargus).
Regarding changes potentially introduced by the railway, it is noteworthy that
total bird densities were reduced from approximately 550 birds/km
2 in 2010–2011
to values in the range 360–390 birds/km
2 range in the following years. This change
occurred shortly after the trains began running, but there is no information from
control sites remote enough to affirm that the decrease was directly associated with
the railway rather than other regional-scale phenomena. Among the local bird
species, some showed a constant growing trend in their densities over the 5-year
study period, including the corn bunting (Emberiza calandra), house sparrow
(Passer domesticus), rock dove, common magpie, and Eurasian skylark (Alauda
arvernsis) (Table 8.1). Some species, such as the crested lark (Galerida cristata),
showed consistently high average densities. Reductions in population density
estimates over time were observed for the common quail (Coturnix coturnix),
European serin (Serinus serinus), common linnet (Carduelis cannabina), meadow
pipit (Anthus pratensis), calandra lark, Spanish sparrow (Passer hispaniolensis),
and red-legged partridge (Alectoris rufa), among others.
Analysis of the spatial distribution of birds around the railway showed a differential use across the species (Table 8.1), though strong seasonal variability
makes it difficult to detect the effects of HSR proximity. This relationship was
negative for a number of species, including the calandra lark, crested lark, rock
dove, and spotted starling. However, it was strongly positive for several species of
finches (common linnet, European serin) that take advantage of the grassland
abundance on HSR embankments. Others, such as the house sparrow, benefitted
from their use of railway structures to nest. In parallel, a specific analysis of largeand mid-sized bird locations showed that both the great bustard and the little
8 Cross-scale Changes in Bird Behavior Around …
121
(Alonso et al. 2005; Morales et al. 2008). For these counts, the car was driven
slowly along dirt tracks up to 1000 m from the railway, with a fixed detection band
of 1000 m to each side of the vehicle. Regular stops were made to prospect the area
thoroughly, including the surroundings of the railway and control sites on both
sides. All morning, censuses were carried out within four hours of sunrise, and
afternoon censuses were done in the 2 h before sunset. Censuses were done on days
with good visibility and no rain, and hunting days were avoided.
In the landscape traversed by the HSR, the avian community was typical of that in
the (Traba et al. 2013). Outstanding species typical of steppes include the great bustard,
little bustard (Tetrax tetrax), and calandra lark (Melanocorypha calandra), together
with others common in agricultural areas, including the spotless starling (Sturnus
unicolor), rock dove (Columba livia), common magpie (Pica pica), sparrows (Passer
spp., Petronia petronia), and several Fringilidae and Embericidae species.
In all, 80 bird species have been detected in the study area, reflecting the
presence of a rich bird community, though 40–50% of the species that have been
observed in the area were detected in fewer than 10 observations within each
sampling period. Eleven species of high conservation interest were present in the
area, including the black kite (Milvus milvus), which is nationally classified as
“endangered” (Madroño et al. 2004). Species classified as “vulnerable” that were
observed in the area include the great bustard, pin-tailed sandgrouse (Pterocles
alchata), black-bellied sandgrouse (P. orientalis) and little bustard as well as
Montagu’s harrier (Circus pygargus).
Regarding changes potentially introduced by the railway, it is noteworthy that
total bird densities were reduced from approximately 550 birds/km
2 in 2010–2011
to values in the range 360–390 birds/km
2 range in the following years. This change
occurred shortly after the trains began running, but there is no information from
control sites remote enough to affirm that the decrease was directly associated with
the railway rather than other regional-scale phenomena. Among the local bird
species, some showed a constant growing trend in their densities over the 5-year
study period, including the corn bunting (Emberiza calandra), house sparrow
(Passer domesticus), rock dove, common magpie, and Eurasian skylark (Alauda
arvernsis) (Table 8.1). Some species, such as the crested lark (Galerida cristata),
showed consistently high average densities. Reductions in population density
estimates over time were observed for the common quail (Coturnix coturnix),
European serin (Serinus serinus), common linnet (Carduelis cannabina), meadow
pipit (Anthus pratensis), calandra lark, Spanish sparrow (Passer hispaniolensis),
and red-legged partridge (Alectoris rufa), among others.
Analysis of the spatial distribution of birds around the railway showed a differential use across the species (Table 8.1), though strong seasonal variability
makes it difficult to detect the effects of HSR proximity. This relationship was
negative for a number of species, including the calandra lark, crested lark, rock
dove, and spotted starling. However, it was strongly positive for several species of
finches (common linnet, European serin) that take advantage of the grassland
abundance on HSR embankments. Others, such as the house sparrow, benefitted
from their use of railway structures to nest. In parallel, a specific analysis of largeand mid-sized bird locations showed that both the great bustard and the little
8 Cross-scale Changes in Bird Behavior Around …
121