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Risk of bird electrocution in power lines: a framework for prioritizing species and areas for conservation and impact mitigation


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Electrocution on power lines is an important human‐related cause of bird mortality and an important conservation issue worldwide. Besides impacts on bird populations, electrocutions cause power outages, resulting in damage to power line network integrity. However, there is a general lack of knowledge on the risk of bird electrocution, especially in developing countries. Generating information over large scales without resorting to local mortality data can be useful for the development of regional management strategies, particularly in countries where electrocution is poorly documented. Here, we developed a framework to model the risk of bird electrocution as an interaction between the species‐specific exposure to power lines (pole density within a species distribution range) and susceptibility (morphological and behavioral traits associated with electrocution hazards). We applied this framework to Brazil, identifying 283 species that face a risk of electrocution, of which 38 were classified as higher risk, mostly raptors (76%). The Pantanal (a large wetland biome) concentrates the greatest cumulative susceptibility due to the high number of species vulnerable to electrocution (i.e. large species using power lines for perching or nesting), while the Atlantic Forest region has a higher risk for electrocution, due to the spatial overlap between the presence of vulnerable species and high exposure to power lines. Furthermore, our study identified spatial patterns of bird electrocution, highlighting priority areas for electrocution susceptibility and electrocution risk to be further investigated, and where measures to mitigate bird electrocutions should be applied on new and existing power lines. Our framework allows a preliminary assessment aimed at identifying areas of higher risk of electrocution, to highlight species vulnerable to this threat and to improve power line routing. This approach can be replicated to other understudied areas of the world where the same information is available.
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Risk of bird electrocution in power lines: a framework for
prioritizing species and areas for conservation and impact
L. D. Biasotto
, F. Moreira
, G. A. Bencke
, M. D’Amico
, A. Kindel
F. Ascens~
1 Programa de P
ao em Ecologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
ucleo de Ecologia de Rodovias e Ferrovias (NERF), Departamento de Ecologia, Universidade Federal do Rio Grande do Sul, Porto
Alegre, Brazil
3 REN Biodiversity Chair, CIBIO/InBIO Centro de Investigac
ao em Biodiversidade e Recursos Gen
eticos, Laborat
orio Associado,
Universidade do Porto, Vair~
ao, Portugal & CIBIO-ISA, Institute of Agronomy, University of Lisbon, Lisbon, Portugal
4 Museu de Ci^
encias Naturais, Departamento de Biodiversidade, Secretaria de Meio Ambiente e Infraestrutura, Porto Alegre, RS, Brazil
5 Theoretical Ecology and Biodiversity Modelling Group - THEOECO, CIBIO-InBIO (University of Porto and University of Lisbon), Tapada da
Ajuda Campus, Lisbon, Portugal
6 Department of Conservation Biology, Do~
nana Biological Station CSIC, Spain
7 Centre for Ecology, Evolution and Environmental Changes (cE3c), Faculdade de Ci^
encias, Universidade de Lisboa, Lisboa, Portugal
avian conservation; electrocution hazard;
power lines; linear infrastructures; risk
assessment; electric utility; pylon
management; impact mitigation.
Larissa D. Biasotto, Programa de P
ao em Ecologia, Universidade
Federal do Rio Grande do Sul, Av. Bento
ßalves 9500, CEP 91501-970, CP 15007,
Porto Alegre, RS, Brazil.
Present address
ucleo de Ecologia de Rodovias e Ferrovias,
Departamento de Ecologia, Universidade
Federal do Rio Grande do Sul, Porto Alegre,
RS, Brazil
Editor: Jeff Johnson
Associate Editor: Stefano Canessa
Received 07 January 2021; accepted 04
August 2021
Electrocution on power lines is an important human-related cause of bird mortality
and an important conservation issue worldwide. Besides impacts on bird popula-
tions, electrocutions cause power outages, resulting in damage to power line net-
work integrity. However, there is a general lack of knowledge on the risk of bird
electrocution, especially in developing countries. Generating information over large
scales without resorting to local mortality data can be useful for the development
of regional management strategies, particularly in countries where electrocution is
poorly documented. Here, we developed a framework to model the risk of bird
electrocution as an interaction between the species-specic exposure to power lines
(pole density within a species distribution range) and susceptibility (morphological
and behavioral traits associated with electrocution hazards). We applied this fra-
mework to Brazil, identifying 283 species that face a risk of electrocution, of
which 38 were classied as higher risk, mostly raptors (76%). The Pantanal (a
large wetland biome) concentrates the greatest cumulative susceptibility due to the
high number of species vulnerable to electrocution (i.e. large species using power
lines for perching or nesting), while the Atlantic Forest region has a higher risk for
electrocution, due to the spatial overlap between the presence of vulnerable species
and high exposure to power lines. Furthermore, our study identied spatial patterns
of bird electrocution, highlighting priority areas for electrocution susceptibility and
electrocution risk to be further investigated, and where measures to mitigate bird
electrocutions should be applied on new and existing power lines. Our framework
allows a preliminary assessment aimed at identifying areas of higher risk of elec-
trocution, to highlight species vulnerable to this threat and to improve power line
routing. This approach can be replicated to other understudied areas of the world
where the same information is available.
Access to electricity is essential to meet basic human needs,
boost economic growth and foster development. Today,
almost all regions of the globe are crossed by transmission
networks, which are continually expanding to underserved
regions (Jenkins, Smallie & Diamond, 2010). However,
despite their benets to humans, power lines can pose a seri-
ous threat to birds by causing direct mortality due to colli-
sion with wires and electrocution (Bernardino et al., 2018;
Biasotto & Kindel, 2018; DAmico et al., 2018). Such mor-
tality can have negative effects on population dynamics and
Animal Conservation  (2021)  ª2021 The Zoological Society of London 1
Animal Conservation. Print ISSN 1367-9430
demography, thus potentially affecting the persistence of spe-
cies over time. Population-level impacts caused by power
lines have been demonstrated, for example, for the Cape vul-
ture Gyps coprotheres (Boshoff et al., 2011), Bonellis eagle
Aquila fasciata (Hern
ıas et al., 2015) and Lud-
wigs bustard Neotis ludwigii (Shaw et al., 2015), and for a
number of other raptor species as reviewed by Slater, Dwyer
& Murgatroyd (2020). Bird electrocutions may also affect
human populations, as they can cause power outages (Bur-
gio, Rubega & Sustaita, 2014; Reed et al., 2014) and wild-
re ignitions (Guil et al., 2018), resulting in economic losses
for companies and customers (Maricato et al., 2016). Thus,
assessing the risk of bird electrocution is relevant from both
biodiversity conservation and economic perspective.
Identifying both species and areas most prone to electro-
cution events is essential to mitigate the impacts of existing
power lines and to improve the planning of new energy cor-
ridors. However, the systematic collection of bird-
electrocution data along power lines has been primarily per-
formed at a local scale, and mainly for the identication of
high-risk structures (Tint
o, Real & Ma~
nosa, 2010; Guil
et al., 2011; Dixon et al., 2017). Upscaling these surveys
from the local scale to larger management areas (at the
regional or country level) can be difcult to achieve due to
the high amount of resources and time required. The alterna-
tive of multiple surveys conducted on a local scale, if not
coordinated, may fail to identify where mitigation and con-
servation efforts are most needed by overlooking areas and
species with higher electrocution risk (Dwyer et al., 2016).
Therefore, generating sound information at large scales with-
out performing extensive eldwork would be highly useful
for identifying those areas where to develop site-based man-
agement strategies (DAmico et al., 2019). This can be par-
ticularly important in countries where electrocution events
are poorly documented and where power line grids are
expanding rapidly (Eccleston & Harness, 2018).
Here, we suggest a framework for an initial risk assess-
ment, at a large scale, using already available data on bird
species and power line networks. The framework is based on
the combination of two types of species-specic information,
namely exposure to power lines and susceptibility to electro-
cution which, when combined, provide an integrated measure
of the electrocution risk (Fig. 1). Exposure is dened as the
likelihood for the individuals of a target species to encounter
an electric pole and is assumed to increase proportionally
with increasing pole density (Dwyer et al., 2016). That is,
when a species inhabits a geographic range with a high pole
density, that species has high overall exposure, and conse-
quently the probability of electrocution occurring increases
(Dwyer et al., 2020). Species susceptibility to electrocution
is mainly inuenced by intrinsic behavioral and morphologi-
cal traits (Bevanger, 1998; Janss, 2000). Birds using power
line structures as poles and wires for perching (Prather &
Messmer, 2010) and nesting (Morelli et al., 2014; Moreira
et al., 2018) are supposed to be more susceptible. Suscepti-
bility also increases with body size (Dwyer et al., 2015), as
electrocution occurs when a bird simultaneously touches
two-phase conductors or one conductor and a ground wire
device on a pole (Janss, 2000). Similar frameworks estimat-
ing risk as a combination of exposure and susceptibility have
been previously proposed to address other impacts related to
linear infrastructures, such as roadkills (Visintin, van der Ree
& McCarthy, 2016; Morelli, Benedetti & Delgado, 2020)
and collision with power lines (DAmico et al., 2019).
Our framework allows a preliminary assessment of poten-
tial electrocution risk for whole bird communities over broad
geographic scales (regional to continental, but potentially
also applicable at a global scale). We applied this framework
to Brazil, the largest megadiverse country, and for which no
specic study or standardized assessment of bird electrocu-
tion has been conducted to date. With rare exceptions, bird
electrocution has been largely neglected in the Neotropics
(Galmes et al., 2017). In Brazil, all information consists of a
few published casualty records and some anecdotal reports
available in the scientic or gray literature. However, the
country has a high species richness in taxonomic or func-
tional groups known to be affected by electrocutions else-
where, and there is no reason to suspect that such casualties
do not occur in a similar way in Brazil. Electrocution also
represents a threat to mammals, a group for which fatality
events are far better documented in Brazil (Lokschin et al.,
2007; Correa et al., 2018). Together, this evidence suggests
that bird electrocution, although currently underreported, is a
real issue that potentially affects many species in Brazil.
Therefore, it is necessary to increase our ability to under-
stand potential electrocution risk patterns across Brazilian
regions. Here, we aimed to answer the following questions:
(1) How is the overall bird susceptibility to electrocution
spatially distributed? (2) How is the potential overall risk of
bird electrocution spatially distributed? (3) Which species
may face a higher risk of electrocution and, therefore, should
receive special attention for conservation and mitigation?
Materials and methods
Study area
Brazil has a large land area (>8.5 M km
), about half of
South America. Both human population growth and urban-
ization rates are unevenly distributed across the country and
demand an extensive and growing energy network (MME,
2019). Thousands of kilometers of power lines traverse the
six Brazilian biomes (Fig. 2), regions with distinct environ-
ments dened according to the prevailing climate and vege-
tation type: Amazon (tropical rainforests), Atlantic Forest
(coastal rainforests), Caatinga (seasonally dry forests), Cer-
rado (tropical savannas), Pampa (subtropical/temperate grass-
lands) and Pantanal (tropical wetlands) (IBGE, 2019). This
environmental heterogeneity affords an exceptional diversity
of birds, accounting for almost 20% of the worlds bird spe-
cies richness (Jetz, Thomas & Joy, 2012).
Power line information
We used the georeferenced database on the distribution of
poles at the country level (updated through November 2018)
2Animal Conservation  (2021)  ª2021 The Zoological Society of London
Assessing the risk of bird electrocution in power lines L. D. Biasotto et al.
Figure 1 A general framework to assess the risk of bird electrocutions. Exposure is measured as the density of electrical infrastructure
within the species distribution and susceptibility is related to the morphological and behavioral traits associated with a higher risk of electro-
cution. This approach allows identifying species and areas with higher electrocution risk.
Figure 2 Workflow to identify target species and areas for bird electrocution prevention/control in eight steps. (1) Identification of geo-
graphic areas with high pole density overall exposure map. (2) Obtaining species-specific exposure maps by overlaying the species distri-
bution areas with the overall exposure map. (3a) Insertion of the wing-length value in the raster maps of the species distribution to generate
the species-specific susceptibility maps. (3b) Cumulative map of susceptibility by summing up all species-specific susceptibility maps. (4a)
Species risk maps obtained by multiplying species-specific susceptibility and exposure maps. (4b) Identification of areas with higher risk of
bird electrocution by multiplying the overall exposure and overall susceptibility maps. (5) Extraction of median value within species risk
maps. (6) Identification of higher-risk species.
Animal Conservation  (2021)  ª2021 The Zoological Society of London 3
L. D. Biasotto et al. Assessing the risk of bird electrocution in power lines
available from the Brazilian Electricity Regulatory Agency
(ANEEL). We selected structures from medium-voltage
power lines (144 kV, n=30 665 490 poles) as these are
the most likely to cause bird electrocutions, because the dis-
tance between the electrical components (wire-wire and pole-
wire) matches the wingspan of several bird species (APLIC,
2006; Lehman, Kennedy & Savidge, 2007; Eccleston & Har-
ness, 2018). Throughout the text, we apply the term pole
to designate all the structures used to support medium-
voltage power lines in Brazil, regardless of their material or
specic conguration, as there is no information available
that allows us to explicitly distinguish between the different
structures (such as wood poles or pylons).
Bird species information
We used the spatial data available from BirdLife Interna-
tional and Handbook of the Birds of the World (www.bird; BirdLife v10, 2017) to obtain georefer-
enced polygons corresponding to the geographic range of
each species. We excluded marine, insular, extinct and
vagrant species according to the latest checklist of Brazilian
birds published by the Brazilian Ornithological Records
Committee CBRO (de Piacentini, 2015). We reconciled the
BirdLife and CBRO datasets for taxonomic inconsistencies
(e.g. use of different scientic names for the same species or
the adoption of divergent species limits for certain taxa).
Whenever a species in BirdLife was treated as two or more
distinct species on the CBRO checklist, we treated them as a
single species in our analyses. This resulted in a working list
of 1668 regularly occurring continental species (87% of the
Brazilian species).
Wingspan is often selected as an indicator of morphologi-
cal susceptibility to electrocution in birds (Bevanger, 1998),
but it is not available for most Brazilian species. We used
wing length as a proxy because this measure often represents
the overall body size better than other univariate traits (e.g.
Wiklund, 1996), and because it correlates well with wing-
span in a wide variety of bird groups (see Supporting Infor-
mation, Figure S1). For the species for which we could not
obtain accurate wing-length data in the literature (n=30, all
passerines), we estimated missing values using a linear
model relating wing length~body length(see Supporting
Information, Figure S2).
To assess the behavioral susceptibility to electrocution, we
classied each species according to its use of poles and
wires for perching or nesting. First, we searched for evidence
of perching or nesting on cables and poles in the online pho-
tographic archive of Brazilian birds WikiAves (www.wikiave This citizen-science platform currently encom-
passes over 3 million photographic records of Brazilian birds
from all over the country. For each species, photographs
were inspected until unequivocal evidence of perching and/or
nesting on poles or wires was found (if any). This meant
that, to be accepted, a record had to clearly show one or
more individuals of the species perched on a power wire or
pole, or with an active nest built on a pole or its associated
structures (transformers, cable supports, etc.). To facilitate
the search for images of nesting behavior, we ltered pho-
tographs with content nestor main actions incubating,
caring for/feeding offspringor building nestusing the
website built-in advanced search tool. For species poorly rep-
resented in the WikiAves database (e.g. rare or restricted-
range species) and lacking evidence of the use of power line
structures, the potential for perching/nesting on poles or
wires was assessed by one of us (G.A.B) based on his exten-
sive eld experience with Brazilian birds and using evidence
accumulated for phylogenetically related species sharing sim-
ilar behavior and habitat preferences.
Modeling framework and analysis
The framework here proposed allows obtaining independent
and complementary maps of susceptibility, exposure and risk
as dened in Fig. 1. We used raster information with the
same extent (Brazilian territory) and a 50 950 km resolu-
tion (n=3419 cells). This resolution is suitable for our pur-
poses since 76% of the 98 Brazilian energy companies
manage areas larger than 2500 km²(equivalent to our pixel
of 50 950 km). In addition, this resolution is recommended
for continental or broad-scale analysis (Hawkins, Rueda &
ıguez, 2008). Therefore, it can be assumed as an appro-
priate scale for regional mitigation planning and manage-
ment. We conducted the analyses at the biome level because
each Brazilian biome contains a distinct bird assemblage and
has unique drivers affecting biodiversity (Souza et al., 2020).
These drivers (land-use and land-cover changes) directly
inuence the rates of urbanization and expansion of the
energy network. There are also several legal and conserva-
tion planning instruments that have been developed and/or
are applied at the biome level and need to be complied by
energy companies. The delimitation of Brazilian biomes fol-
lowed IBGE (2019).
We started by building an overall exposure map based on
the electricity pole distribution at the country level (see
Power line information section), described as the density of
medium voltage poles per unit area (50 950 km grid cell
or km²) (Fig. 2, step 1). The value of pole density was log
transformed to reduce the importance of the few cells con-
taining very large urban areas and correspondingly very high
pole densities. We derived species-specic exposure maps
(Fig. 2, step 2) for the subset of behaviorally susceptible
species (i.e. those species identied as using cables and/or
poles; see Bird species information section) by clipping the
overall exposure map with the polygon of distribution of
each species.
Similarly, we built species-specic susceptibility maps
(Fig. 2, step 3A) by using the wing length (in mm) as a sus-
ceptibility indicator and assigning this value to each pixel of
each individual species map. We then obtained the overall
susceptibility map for Brazil by summing all species-specic
susceptibility maps (Fig. 2, step 3B). We chose to work with
the cumulative susceptibility because we assume that all spe-
cies using power line structures have some risk of electrocu-
tion, even the small ones. Thus, this metric indicates the
accumulated susceptibility for each pixel, considering only
4Animal Conservation  (2021)  ª2021 The Zoological Society of London
Assessing the risk of bird electrocution in power lines L. D. Biasotto et al.
those species that use power line structures. From this over-
all susceptibility map, we estimated the median value of sus-
ceptibility for each biome.
Using these information layers, we further derived
species-specic maps of electrocution risk by multiplying the
species morphological susceptibility (i.e. wing length) and
exposure maps (Fig. 2, step 4A). To obtain the map of over-
all electrocution risk in Brazil (Fig. 2, step 4B), we multi-
plied the overall exposure map by the overall susceptibility
map, from which we also extracted the median risk for each
biome. The species-specic maps of electrocution risk were
used to rank species according to their median risk (within
their respective distribution ranges) (Fig. 2, step 5). To iden-
tify the subset of species potentially most affected by elec-
trocution (i.e. with higher median risk values), we split the
ranking into different classes using the method proposed by
Jiang (2013) for data with heavy-tailed distributions. The
method partitions the class intervals and so establishes the
number of classes through an iterative multistep approach.
The rst step splits data values around the mean into two
parts (head and tail); the next step splits the above-average
values again into head and tail by the new mean, and so on
until the head values are no longer heavy-tailed. Each mean
corresponds to the upper limit of a class. This approach
resulted in three classes, interpreted by us as species with
higher,intermediateand lowerelectrocution risk,
respectively (Fig. 2, step 6). We used this objective classi-
cation to reduce arbitrariness in the assignment of classes, as
we do not have data to establish a clear relationship between
risk level and priority level, which should ideally be dened
on a local or case-by-case basis. We considered higher-risk
species to be of greatest concern for conservation and miti-
gation actions at the national scale.
Finally, the overall exposure map, the species-specic
maps, and the nal susceptibility map were normalized to 0
1 values according to the minimum and maximum values in
each map, with 0 being assigned to the grid cells with the
lowest observed value and 1 to the grid cells with the high-
est observed value. This facilitates comparisons since all
maps are on the same scale and ensured that the values of
the input maps (exposure and susceptibility) had equal
weights when multiplied to produce the risk map. We per-
formed all spatial analyses in R environment (R Core Team,
2020) and the R packages sf(Pebesma, 2018), fasterize
(Ross, Sumner & Al, 2020), raster(Hijmans & van Etten,
2020), classInt(Bivand, 2020) and rgdal(Bivand et al.,
2020). Map layouts were made using ArcGIS 10.3 (ESRI,
Pole density across the country ranged from 0 to 260 poles/
(Table 1). Extensive areas in the Amazon (more than
half of the biomes land surface) and Pantanal, and a few
areas in the Cerrado, had very low pole densities (Fig. 3a).
The Atlantic Forest, Pampa, Caatinga and the rest of the
Cerrado had considerably higher and more homogeneous
pole densities (Fig. 3a).
We found direct evidence of the use of power lines for
perching and/or nesting for 242 bird species, and we further
identied another 41 species that potentially use power line
structures, totaling 283 species (Supporting Information,
Table S1). Pantanal was the biome with the highest cumula-
tive bird susceptibility to electrocution (Fig. 3b). Some areas
of Cerrado adjacent to Pantanal also showed high cumulative
susceptibility (Fig. 3b). At the other extreme, the Amazon
showed the lowest median of cumulative susceptibility
(Fig. 3b). The overall pattern does not change when only
species with direct evidence of the use of power line struc-
tures are included in the analyses (242 species) (see Support-
ing Information, Figure S3). The Atlantic Forest showed the
highest electrocution risk (median values), followed in order
by Cerrado, Pantanal, Pampa, Caatinga and Amazon
(Fig. 4).
We identied 38 species with higher electrocution risk
(13% of the analyzed species) (Fig. 5), having a median risk
ranging between 0.25 and 0.57. Most of the higher risk spe-
cies were raptors (76%). The three species with the highest
risk values were the jabiru Jabiru mycteria (a very large
stork), the black-chested buzzard-eagle Geranoetus
melanoleucus and the crowned eagle Urubitinga coronata.
The risk within each species range was highly variable
across species, but some species such as the black-chested
buzzard-eagle and the crowned eagle had a small interquar-
tile range over high-risk values, denoting a high pole density
across their entire distribution ranges (Fig. 5). Of the remain-
ing species, 51 were classied as intermediate risk(18%;
0.100.25) and 194 as lower risk(67%; 0.000.10) (Sup-
porting Information, Figure S4).
Electrocution is probably one of the main causes of human-
induced bird mortality (Loss, Will & Marra, 2015; Slater
et al., 2020), but for many regions in the world, there is still
no information on the extent of this impact. We provided a
framework that allows a preliminary assessment of the spa-
tial distribution of bird exposure and susceptibility, which
combined provide the potential risk of electrocution. The
framework is based on available information, including the
Table 1 Pole density of medium voltage power lines (144 kV) in
the six Brazilian biomes. Biomes are arranged by the median pole
Range pole
Mean (SD) pole
Median pole
0.5259.8 13.1 19.8 9.7
Pampa 0.568.3 6.0 7.8 4.5
Caatinga 0.125 4.4 3.3 3.6
Cerrado 0.063.8 3.8 4.7 2.6
Pantanal 0.05.4 0.6 1.0 0.1
Amazon 0.048.4 0.8 2.3 0.0
Animal Conservation  (2021)  ª2021 The Zoological Society of London 5
L. D. Biasotto et al. Assessing the risk of bird electrocution in power lines
Figure 3 Summary results for exposure and susceptibility to electrocution, for 283 species with behavioral characteristics associated with a
higher risk of electrocution: (a) overall exposure map based on pole density of medium voltage power lines (144 kV) (raw values of pole
density were log transformed to reduce the high relative weight of a few areas in the Atlantic Forest, (see Table 1); (b) overall susceptibility
map based on distribution area and wing length. In both panels, pixel values were normalized to a 01 scale. Boxplots represent the
interquartile range (IQR; box), the median (vertical bar), the 1.5 9IQR interval (whiskers) and the outliers (dots).
Figure 4 Overall risk of bird electrocution relating power pole density to bird susceptibility map. Boxplots represent the interquartile range
(IQR; box), the median (vertical bar), the 1.5 9IQR interval (whiskers) and the outliers (dots).
6Animal Conservation  (2021)  ª2021 The Zoological Society of London
Assessing the risk of bird electrocution in power lines L. D. Biasotto et al.
density of electrical infrastructures within a speciesrange,
and morphological and behavioral traits associated with a
higher risk of electrocution.
The application of the framework to Brazil indicated the
Atlantic Forest as the biome with the highest risk of bird
electrocution, a condition resulting from a high pole density
combined with a high number of susceptible species occur-
ring therein. The Atlantic Forest concentrates more than 60%
of the Brazilian human population (Scarano & Ceotto,
2015), so it is not surprising that it has the highest pole den-
sity (Ribeiro et al., 2009). The most cost-effective method to
reduce bird electrocution in areas that already accommodate
such a dense electrical network is the adoption of mitigation
measures in strategic sites, including the retrotting of wood
poles (Dwyer, Harness & Eccleston, 2017) or pylons (Che-
vallier et al., 2015; Dixon et al., 2019) whose design poses
a risk of electrocution. In areas classied as higher risk,
under our framework, such as the Atlantic Forest, a more
focused investigation can be applied to search for data on
fatalities or power system failures assigned to electrocutions
and to evaluate the relationship between landscape composi-
tion and electrocution events (e.g. Hern
ıas et al.,
2020). The pole location and conguration are important in
determining the risk of mortality at the local scale (Mojica
et al., 2018) and to inform the best mitigation interventions.
Our approach indicates where electric companies and conser-
vation biologists can focus their attention to perform detailed
assessments aimed at identifying high-risk poles. For exam-
ple, it is known that a combination of high pole density,
prey abundance and few natural perches can increase electro-
cution risk for some raptor species (P
ıaet al.,
Our results also showed that the Pantanal and surrounding
areas concentrate the highest cumulative susceptibility (i.e.
the highest concentration of species vulnerable to electrocu-
tion). Although this biome and the Amazon currently experi-
ence high rates of agricultural expansion, they still have
relatively few energy infrastructures (Souza et al., 2020),
including power lines. However, the Pantanal can become a
central area for future projects of infrastructure expansion
that will connect the Amazon to central Brazilian regions
(Hyde, Bohlman & Valle, 2018; Vilela et al., 2020). Our
results indicate that the routing of new transmission lines
through the Pantanal can lead to a signicant increase in the
risk of electrocution for susceptible species. Consequently,
we recommend that these new facilities are carefully planned
Figure 5 Variation in electrocution risk for 38 bird species with higher risk of electrocution. Boxplots represent the interquartile range (IQR;
box), the median (vertical bar), the 1.5 9IQR interval (whiskers) and the outliers (dots). Gray boxes represent raptor species. Common
names in bold represent globally threatened species according to the IUCN Red List of Threatened Species (BirdLife International, 2021).
Animal Conservation  (2021)  ª2021 The Zoological Society of London 7
L. D. Biasotto et al. Assessing the risk of bird electrocution in power lines
and, if it is not possible to avoid the most sensitive areas,
the new power lines should at least be built with appropriate
mitigation measures and considering the behavior and mor-
phology of the most susceptible species.
Thirty-eight bird species were ranked as higher risk of
electrocution in our study. Specic guidelines for protection
against electrocution should be delineated for these species,
which should further receive special attention during the
environmental licensing of new power lines. We found that
birds of prey predominate among our higher risk species. In
particular, the globally threatened crowned eagle, white-
collared kite Leptodon forbesi and white-necked hawk
Amadonastur lacernulatus are of special concern because the
electrocution of even a few individuals can potentially cause
serious population-level impacts. Raptors are top predators
and are well known for using cables and poles to perch (Sla-
ter et al., 2020). Overall, they have a delayed maturity, low
fertility rates and smaller population sizes, thus electrocution
events may have severe implications for their population
dynamics and persistence over time (Eccleston & Harness,
2018; De Pascalis et al., 2020; Slater et al., 2020). In our
ranking, the black-chested buzzard-eagle and the endangered
crowned eagle occupied the top positions. These results are
in line with studies performed in neighboring semiarid areas
of central Argentina, where the former species accounts for
numerous electrocution records (Ibarra & De Lucca, 2015)
and the latter has been shown to be disproportionately
affected by electrocution considering its low population
density (Galmes et al., 2017; Sarasola, Galmes & Watts,
Likewise, parrots (order Psittaciformes), represented in our
higher-risk class by the endangered lears macaw Anodor-
hynchus leari and hyacinth macaw Anodorhynchus hyacinthi-
nus, stand out for their curiosity and social behavior when
interacting with power line structures (Seibert, 2006). They
often peck the structures and interact closely with pole ele-
ments like jumpers and energized wires, and most commonly
in small ocks. Galmes et al. (2017) reported two of the
three species of parrots in Argentina as victims of electrocu-
tion, suggesting that this is indeed an important mortality
factor for this group, at least in certain regions. In general,
parrots are long-lived birds, and many species have naturally
restricted ranges and are threatened with extinction (Berkun-
sky et al., 2017). We strongly recommend that particular
attention be paid to these threatened macaws and parrots, for
example by carefully considering the pole design to be used,
ideally tailored for both raptors and for this group, since
measures to mitigate the electrocution of raptors may not be
sufcient or suitable for parrots.
Further developments of the framework
We acknowledge some limitations of our framework and
reinforce that it should be considered a rst approach to
identify regions and species that need more attention and
should be targeted for a more in-depth data collection pro-
cess. We highlight some features that could be rened to
improve the effectiveness of the framework.
First, some authors argue that the use of pole density as a
single surrogate for bird exposure to electrocution can com-
promise the results because this approach ignores habitat
availability and conguration in hazard pole arrangement
ıaet al., 2017; Hern
no, S
Agudo & Carbonell, 2018). In our study, we used pole den-
sity as a proxy for exposure to electrocution because there is
no systematic information on electrocution hazards for any
part of the Brazilian territory (and for many other countries),
thus preventing approaches that identify the most problematic
pole congurations. Yet, it has been shown that the probabil-
ity of electrocution increases with pole density (Guil et al.,
2011, 2015; Dwyer et al., 2020). We strongly recommended
that future replications of our framework include information
about pole/pylon conguration whenever available, in order
to rene the electrocution risk as it is inuenced by ground-
ing, pole and crossarms material, conductor and wire
arrangement, insulators, exposed jumpers and other technical
elements (Tint
oet al., 2010; Dwyer et al., 2017).
Second, the use of the wing length and perching/nesting
behaviors as the sole predictors of susceptibility may seem
reductionist. These traits, however, can be easily obtained,
allowing a preliminary assessment of a vast pool of species
as ours, similarly to previous approaches that looked at the
risk of bird collision with wires and wind turbines (Beston
et al., 2016; Santangeli et al., 2018; DAmico et al., 2019).
Our framework also does not integrate information on spe-
cies abundance, or species-specic patterns of frequency and
temporal use of the infrastructures. Resident species, for
example, can have higher temporal exposure to poles than
migratory species. On the other hand, a migratory species
that spends its non-breeding period in low-risk areas might
at least theoretically be signicantly affected if it passes
through high-risk areas during migration. While the inclusion
of such information would greatly improve the ability to
identify higher risk areas at ner resolutions or with larger
condence, we currently have no information about these
speciestraits. However, this information may be available at
smaller scales or for some target species or groups.
Third, although we have explicitly indicated species that
should receive special attention, we recommend caution
when interpreting the terms intermediateand lowerrisk,
as our rating provides a value that can only be used for
comparisons within our species pool. All 283 species ana-
lyzed face some risk of electrocution, due to their use of
energy structures. Some smaller species, despite their size,
show gregarious nesting behavior or build bulky nests of
sticks. The monk parakeet Myiopsitta monachus, for example
builds large communal nests that greatly increase the risk of
electrocution and power outages (Burgio et al., 2014).
Fourth, we were unable to verify or validate our results
because bird electrocutions are under-reported and understud-
ied in Brazil. We hope that our results will stimulate hypoth-
esis testing and encourage electrocution surveys aimed at
higher-risk areas and species to further improve the frame-
work. Finally, the grid resolution used here is rather coarse
for mitigation planning and routing at local scales. For
example, it is not appropriate to indicate the most suitable
8Animal Conservation  (2021)  ª2021 The Zoological Society of London
Assessing the risk of bird electrocution in power lines L. D. Biasotto et al.
corridors for new power lines or to identify specic poles to
be mitigated. However, our spatial scale is applicable for
planning the expansion of the energy network, especially in
countries where there is a long distance between the power
plants and the main energy-consuming regions, such as Bra-
zil (Cardoso J
unior, Magrini & da Hora, 2014). The out-
comes of our framework can be ne-tunedfollowing a
systematic process of data renement. The bird distribution
and pole conguration databases are key elements to be
improved for ne-scale studies.
Our framework allows recognizing target regions and species
to receive special attention in bird electrocution assessments,
fostering win-win situations that will simultaneously prevent
bird fatalities and power outages. We recommend rening the
scale in higher-risk regions and for higher-risk species. The
method proposed here can be replicated in any geographic
area of the world where bird electrocutions are poorly studied
and where information on birds and power lines is available.
We thank Brazils Access to Information Law and ANEEL for
making power line spatial data available to this study. We thank
Luis Borda de Agua and Vinicius A. G. Bastazini for reading a
previous version of the paper. We also thank the associate editor
and two anonymous reviewers for helpful suggestions that
greatly improved the paper. This study was nanced by the Coor-
ao de Aperfeic
ßoamento de Pessoal de N
ıvel Superior
(88882.345595/201901) Brazil (CAPES) Finance Code 001
through Portal de Periodicos´and also scholarships granted to
LDB under the Programa de Excel^
encia Acad^
emica (PROEX).
MD and FA were funded by Fundac
ao para a Ci^
encia e
Tecnologia (CEECIND/03798/2017 and CEECIND/03265/
2017, respectively). FM was supported by the Portuguese
Science and Technology Foundation (FCT), through contract
Authors’ contributions
Conception and design were conducted by LB, FM, MD,
AK and FA. Data collection was performed by LB and
GAB. Data preparation and analysis were performed by LB
and FA. The rst draft of the paper was written by LB. All
authors commented and critically reviewed this and subse-
quent versions of the paper. All authors read and approved
the nal paper.
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Supporting information
Additional supporting information may be found online in
the Supporting Information section at the end of the article.
Animal Conservation  (2021)  ª2021 The Zoological Society of London 11
L. D. Biasotto et al. Assessing the risk of bird electrocution in power lines
Figure S1. Linear regression model relating wingspan (de-
pendent variable) and wing length (independent variable) for
129 species of Brazilian birds belonging to 36 taxonomic
Figure S2. Linear model relating bird wing length ~body
length measures.
Figure S3. Map of electrocution susceptibility for 242 spe-
cies of Brazilian birds that had their use of poles or wires
for perching or nesting conrmed by examination of WikiA-
ves photographs.
Figure S4. Classes and class intervals of bird electrocution
risk as dened by the application of the clustering algorithm
scheme of Jiang (2013) for data with a heavy-tailed distribu-
Table S1. Information on susceptibility and risk of electrocu-
tion for 283 Brazilian bird species.
12 Animal Conservation  (2021)  ª2021 The Zoological Society of London
Assessing the risk of bird electrocution in power lines L. D. Biasotto et al.
... The resulting maps will allow for a preliminary assessment aimed at identifying areas where electrocutions and/or collisions may be having a significant impact on wildlife (for example, in UICN, In press). This will then be useful for the development of regional management strategies (Biasotto et al., 2021). ...
... Analysis of the data recorded in the register together with information on the presence of sensitive species and the existence of areas important for these species or protected areas, among other factors, makes it possible to identify and delimit at-risk, sensitive and priority areas. GIS and sensitivity mapping tools can be used to map areas where potential collisions and electrocutions might be expected, and/or where poorly planned and dangerous power lines may have significant impacts on the conservation of the most susceptible species present (for bird sensitivity maps see, for example, Pérez-García, 2014; Red Eléctrica Española, 2017;D'Amico et al., 2019;Derouaux et al., 2020;Biasotto et al., 2021;UICN, In press). See Sections 7.2-7.4 ...
... Garthe & Hüppop, 2004; Bright et al., 2008;McGuinness et al., 2015).In the case of power lines, there are examples of maps prepared for bird sensitivity to electrocution (Pérez-García, 2014) and collisions (Red EléctricaEspañola, 2017;D'Amico et al., 2019;Biasotto et al., 2021). The sensitivity scores were based on characteristics such as the species' conservation status, anatomy, behaviour, preferences and habitat use(Figure 163). ...
Full-text available
Guidelines for preventing and mitigating wildlife mortality associated with electricity distribution networks
... Parrots, and particularly macaws, are vulnerable to electrocution (Biasotto et al. 2021), but few studies have focused on these birds. There are anecdotal records of electrocutions for the Burrowing Parrot Cyanoliseus patagonus and Monk Parakeet Myiopsitta monachus in Argentina (Galmes et al. 2017) and the Golden Parakeet Guaruba guarouba in Brazil (Vilarta et al. 2021), and the last wild Spix's Macaw Cyanopsitta spixii died due to electrocution (Juniper 2004). ...
... There are anecdotal records of electrocutions for the Burrowing Parrot Cyanoliseus patagonus and Monk Parakeet Myiopsitta monachus in Argentina (Galmes et al. 2017) and the Golden Parakeet Guaruba guarouba in Brazil (Vilarta et al. 2021), and the last wild Spix's Macaw Cyanopsitta spixii died due to electrocution (Juniper 2004). Both blue macaw species, Hyacinth Macaw Anodorhynchus hyacinthinus and Lear's Macaw A. leari, were recently identified as having a high risk of electrocution due to their morphological and behavioural characteristics, as well as the high density of power poles within their distribution ranges, providing yet another reason for concern about their conservation status (Biasotto et al. 2021). ...
... Parrot bills are very strong, and their bite can easily destroy deterrent structures such as plastic spikes or insulator covers. Ultimately, mitigation measures designed for raptors are unlikely to be useful for parrots (Biasotto et al. 2021). ...
Electrocution can pose a serious threat to large birds, particularly to threatened species with low population sizes. However, few studies have focused on the impacts of electrocution on large parrots such as the Endangered Lear’s Macaw (Anodorhynchus leari), endemic to the Brazilian Caatinga. Here, we compile and describe 31 electrocution events, as reported by villagers, indicating that electrocution may be an important threat to the Lear’s Macaw. We suggest a research and monitoring agenda to better understand the spatial and temporal patterns of this impact and recommend some immediate mitigation measures for decreasing electrocutions.
... Esta medida é apontada por Marques et al. (2014), como a mais eficiente para minimizar as colisões. Desligar as turbinas temporariamente quando uma espécie de interesse está sob risco pode ser feito para períodos programados e predefinidos do dia/noite de acordo com picos de atividade das espécies, ou sazonalmente durante temporadas de migração; Biasotto et al. (2021) modelaram o risco de eletroplessão de diferentes espécies da avifauna brasileira de forma a identificar as que necessitam de maior atenção para medidas de mitigação, e apontam que diferentes medidas mitigadoras, visando minimizar o risco de colisões, têm sido propostas. Entre essas medidas temos o replanejamento da localização de linhas de energia para formar corredores de voo, instalação de cabos subterrâneos, alterações no desenho de torres, linhas de energia com diferentes níveis de cabos para-raios ou a remoção dos mesmos e a sinalização de cabos para-raios com diferentes dispositivos. ...
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O planejamento inicial de um empreendimento eólico é um processo-chave e, nessa fase, é crucial que se tenha a melhor compreensão possível dos potenciais impactos da atividade sobre os locais avaliados. Além dos custos específicos do projeto e receitas esperadas, qualquer avaliação de sua viabilidade e decisão sobre onde instalar o empreendimento devem considerar os custos ambientais e para a biodiversidade. O planejamento antecipado da seleção do local de instalação considerando as alternativas de menor risco para a biodiversidade e a reflexão prévia sobre medidas de mitigação de impactos mais eficazes disponíveis são fundamentais. Uma seleção cuidadosa do local e da configuração do parque eólico pode reduzir de forma relevante o impacto sobre a biodiversidade e eventuais riscos ao empreendimento, por isso essa é a etapa mais importante e merece especial atenção, tanto por parte dos órgãos licenciadores quanto do empreendedor.
... Complementarily, the establishment of priority management zones based on predictive electrocution models can be a very useful tool for decision-makers when establishing protection zones (Pérez-García et al., 2017;Hernández-Lambraño et al., 2018;Hernández-Matías et al., 2020). A recent study has developed a predictive map of risk of electrocution for Brazil to prioritize species an areas of interest (Biasotto et al., 2021). In some areas where species of conservation concern exist (the Endangered Chaco Eagle) mitigation measures already started (Sarasola and Zanón-Martínez, 2017), but efforts should be implemented more widely along the sub-continent. ...
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Power lines endanger birds around the world, as a large number of them are killed every year through electrocutions and collisions. This problem can have severe consequences at population level, particularly for threatened species. While this threat has been widely studied in different parts of the world, information from South America is scarce. Here, we review information from scientific and grey literature on the collision and electrocution of birds on power lines from this sub-continent. We complement this information with novel data provided by a citizen science project, electrical companies and field monitoring records. Our results show that although in South America scientific and anecdotal information on this topic is scarce, data suggests that this threat is present in many areas of this sub-continent and affects several species, some of which are seriously threatened. However, information on the most affected species, the number of individuals impacted, the most dangerous geographical areas and the effectiveness of mitigation action is scarce and mainly anecdotal. This is worrying, because South America is a hot spot of biodiversity with many threatened and endemic bird species. We urge conservationists to evaluate this problem in more detail, define areas where it is important to avoid power line installation and establish priority areas for implementation of effective mitigation actions. Scientific evidence shows that dangerous power lines require retrofitting, but this knowledge should also be applied to the new energy facilities and the establishment of national regulations, which would undoubtedly reduce the impact of this infrastructure on wildlife.
... Our framework can be adapted to other environments. For example, in open habitats as wetlands, savanas, or even deserts, impacts as bird collisions and electrocutions can be more urgent (Uddin et al., 2021), and therefore anticipated with similar approaches to those proposed by D' Amico et al. (2019) and Biasotto et al. (2021), used as a layer during route planning with the general workflow proposed here. ...
Building new power lines is fundamental to supply the growing energy demand worldwide. Transmission Lines (TLs) impact assessments focus less on the first level (avoidance) of the mitigation hierarchy (MH) and more on the inferior levels (minimization, restoration, and compensation). Thus, designing TLs routes that avoid adverse environmental effects becomes an important challenge. Unfortunately, the environmental perspective is still poorly considered and incorporated too late into the projects, causing conflicts in the assessments due to divergent stakeholders' opinions. Identifying conflicting areas early is essential to avoid adding cost and delay to the project. Here, we proposed a decision workflow of route design which includes: i) the proposal of alternative routes using Geographic Information System and Least Cost Path Analysis based on two sets of fuzzy criteria – engineering and environmental; ii) an experimental approach with gradual variation among five scenarios that integrate engineering and environmental perspectives, based on Spatial Multi-criteria Analysis and Analytic Hierarchy Process; and iii) identification of route segments characterized by consensus between engineering and environmental perspectives, using a moving window analysis. Our findings show that the scenarios with the higher influence of environmental criteria achieved better performances in all environmental metrics. The spatial convergence among segments of all five modeled alternatives represents less conflict between environmental and engineering perspectives. We recommend that impact assessment of power lines should start taking advantage of the first level of the mitigation hierarchy (impact avoidance). This will represent a gain in the effectiveness of the impact assessment outcomes, a better focus on residual impacts during the following MH phases, a decrease in conflict level during the licensing process, and a potential reduction in project implementation time.
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Power lines are infrastructures continuously expanding worldwide to supply the human population’s demands for electricity. Poorly planned power line networks may represent a risk for biodiversity by crossing sensitive areas, resulting in different impacts such as habitat loss and degradation, and by promoting wildlife fatalities. Considering that part of the impacts persists throughout the operation phase, it is also necessary to pay attention to the installed energy grid, promoting efficient impact mitigation measures. This doctoral thesis was elaborated to improve the knowledge and the research on how power lines impact the environment in which they are installed, contributing to a better integration of environmental aspects in its planning and aiming at the mitigation of different impacts. In Chapter 1 I present a systematic approach to compare alternative routes of power lines and indicate the route with the lowest environmental impact, focusing on the avoidance of forest loss. Additionally, I identify route segments where a consensus between engineering and environmental considerations exists. This procedure identifies geographic-divergent segments, enabling the early identification of areas with potential conflicts where impact minimization needs to be negotiated. In Chapter 2 I develop a framework to model the risk of bird electrocution in Brazil as an interaction between the species-specific exposure to power lines (pole density within a species distribution range) and susceptibility (morphological and behavioral traits associated with electrocution hazards). This study identifies spatial patterns of bird electrocution, highlighting priority areas of electrocution susceptibility, electrocution risk, and the more vulnerable species to this impact. In Chapter 3 I report electrocution deaths of the endangered Lear’s Macaw, a species indicated as priority in relation to the risk of electrocution in the previous chapter. I describe possible causes and patterns of fatality records, highlight the importance of considering electrocution risks as an overlooked threat, and I suggest some effective and efficient mitigation measures aimed at reducing the impact of power lines along the species distribution area. In Chapter 4 I briefly remark the main structural aspects of roads and power lines considering their attributes, global extension, effect zone, and I shortly review the similarities and differences in the top-five impact categories common to both. In addition, I identify some knowledge gaps that should be further explored in power line and road research agenda. This thesis explores approaches that can be adapted and used in a decision-making context, regarding planning and network expansion and environmental licensing of individual projects. This thesis also has important contributions from the Mitigation Hierarchy perspective, with some of its different steps covered in the chapters presented here.
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Censusing wintering raptors has proved useful in detecting changes in populations. Israel is a well-known bottleneck for soaring birds in the autumn and the spring. Despite the many studies on migratory raptors in Israel, none have undertaken the study of the overwintering raptors consistently over extended periods, such as 1985-2022, a period of 38 years. During the study, conducted in central Israel, we recorded 44,120 individuals from 32 species. The most frequently observed species were Black Kite (Milvus migrans; 59.1%), Common Kestrel (Falco tinnunculus; 18.1%), and Steppe Buzzard (Buteo vulpinus; 6.6%). We found an increase in the total number of individuals, where the mean increase compared to the starting year was 851.6 ± 1071.2%, and the average annual growth was 43.7 ± 158.8%, respectively. A similar pattern was found in the number of species during the study period, where the mean annual increase was 17.1 ± 20.5%, and the average annual growth rate of species richness was 2.2 ± 16.2%. However, an evaluation of the mortality from power lines of two listed species suggests that the wintering raptors are not well protected in the study area. The conservation of these raptors and the possible sustainability of their wintering populations into the future, some of which are on the IUCN Red List, are of great importance, and the authorities should try and understand the human demographics and mesohabitat changes that appear to influence the wintering capabilities of the raptor populations.
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Brazil has a monitoring system to track annual forest conversion in the Amazon and most recently to monitor the Cerrado biome. However, there is still a gap of annual land use and land cover (LULC) information in all Brazilian biomes in the country. Existing countrywide efforts to map land use and land cover lack regularly updates and high spatial resolution time-series data to better understand historical land use and land cover dynamics, and the subsequent impacts in the country biomes. In this study, we described a novel approach and the results achieved by a multi-disciplinary network called MapBiomas to reconstruct annual land use and land cover information between 1985 and 2017 for Brazil, based on random forest applied to Landsat archive using Google Earth Engine. We mapped five major classes: forest, non-forest natural formation, farming, non-vegetated areas, and water. These classes were broken into two sub-classification levels leading to the most comprehensive and detailed mapping for the country at a 30 m pixel resolution. The average overall accuracy of the land use and land cover time-series, based on a stratified random sample of 75,000 pixel locations, was 89% ranging from 73 to 95% in the biomes. The 33 years of LULC change data series revealed that Brazil lost 71 Mha of natural vegetation, mostly to cattle ranching and agriculture activities. Pasture expanded by 46% from 1985 to 2017, and agriculture by 172%, mostly replacing old pasture fields. We also identified that 86 Mha of the converted native vegetation was undergoing some level of regrowth. Several applications of the MapBiomas dataset are underway, suggesting that reconstructing historical land use and land cover change maps is useful for advancing the science and to guide social, economic and environmental policy decision-making processes in Brazil.
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Electrocution is a widespread conservation problem for birds of prey that has received little attention in the Neotropics. Here we present electrocution records involving the endangered Chaco Eagle (Buteogallus coronatus) in central Argentina, and we provide information on the power pole structural characteristics associated with electrocutions. Nine Chaco Eagles were recorded electrocuted during the period 2012–2019 over an area of 9000 km2. Chaco Eagles were found electrocuted in association with five types of power poles, but more than half the electrocutions (55%) were on poles made of steel-reinforced concrete and with jumper wires above the crossarms. With the addition of four previous electrocution reports in this region during the same time period, the annual rate of Chaco Eagle electrocutions was similar to the rate of mortality by other human-related factors such as direct persecution. Future conservation actions and research should focus on retrofitting the small fraction of poles that pose the highest electrocution risks for Chaco Eagles, and on assessing the demographic effects of electrocution mortality for this species and other endangered raptors in Argentina.
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Avian electrocutions on power poles affect raptor populations globally. Mitigation strategies in the USA are typically bottom-up, combining risk assessments for individual poles into a utility-specific avian protection plan. This approach is usually reactive, relying on incidental documentation of electrocutions for initiation, and can allow uncoordinated mitigation strategies among adjacent utilities. A top-down strategy may help solve both problems if maps identifying where distribution power poles occur were available for comparison to range maps for species at risk of electrocution. Range maps exist but pole location data are rarely publicly available in the USA. Pole-density models were previously created for Colorado and Wyoming, the Great Basin, and the Columbia Plateau because pole density can serve as a surrogate for electrocution risk. We used each of these models to predict pole densities throughout four additional areas: the Northwestern Plains, Southwestern Plains, Southwestern Plateaus, and parts of New Mexico not included in other modeled areas. We also applied the Colorado and Wyoming model to portions of the Uinta Basin and Wyoming Basin projecting from Colorado and Wyoming into Idaho and Utah. The Colorado and Wyoming model fit all areas better than other models, except parts of New Mexico not included in other modeled areas, where the Great Basin model fit best. Our model predictions facilitate assessment of pole density across much (2,573,746 km²) of the western USA. To assess whether the models are useful in predicting electrocutions, we compared predicted pole densities throughout White Sands Missile Range to locations of 59 avian electrocutions. Electrocutions occurred at low rates in cells with low predicted pole densities, and at higher rates in cells with moderate and high predicted pole densities. Because the models do not include species-specific information, they have the potential to be applicable to the conservation of a wide variety of species.
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Non-natural mortality is a major threat to animal conservation worldwide. Its origins are extremely diverse and include infrastructures that cause animal casualties. Its effects are widely felt and so prioritization criteria are necessary when implementing mitigation actions. Most of the threats causing non-natural mortality have in common the fact that they are distributed unevenly across several spatial scales. Thus, here we present a protocol for prioritizing conservation measures in: (i) population fractions suffering from high levels of non-natural mortality whose demographic effects are the most serious, and in (ii) areas with the highest risk of casualties due to heterogeneities in both spatial use by individuals and the inherent hazards of the infrastructures causing mortality. To do so, the protocol consist of 5 steps: 1) to identify sink populations over large geographical areas; 2) to identify sink areas of high mortality within target populations; 3) to identify areas intensively used by individuals in target areas; 4) to identify spatial points or individual infrastructures showing high mortality risk; and 5) using direct evidence of casualties to complete information on high-risk sites and infrastructures. To show the potential of this protocol, we use as an example the mitigation of mortality due to electrocution in Bonelli's eagle in SW Europe, where this species is of conservation concern. Thanks to the retrofitting of dangerous pylons, we demonstrate that our protocol can help restore Bonelli's eagle territories to levels that will ensure the persistence of the studied population. In addition, we show that our criteria enhance the optimization of resource investment in mortality mitigation as our criteria identify the pylons with the most devastating effects on the population. To summarize, we provide the basis for a framework applicable to many different species and scenarios whose costs in terms of mitigation actions and benefits in terms of population viability prospects can be explicitly calculated.
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Significance In the next 5 y, more than 10 thousand kilometers of roads will be built or improved in the Amazon. Well-designed projects can increase employment opportunities, reduce transport costs, and support regional development. However, roads will also drive deforestation, threatening biodiversity and ecosystem services, jeopardizing the welfare of indigenous people, and moving the biome toward irreversible shifts in vegetation. Data to support good decisions are remarkably scarce. Typical feasibility studies, where they exist, inadequately address environmental and social impacts and do not facilitate comparison across projects. This study contributes to informed decision-making by quantifying the environmental, social and economic effects of 75 planned projects. It demonstrates that fewer projects in carefully chosen locations would dramatically improve outcomes of all types.
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Since 2005, the Brazilian Ornithological Records Committee (CBRO) has published updated checklists of Brazilian birds almost every year. Herein, we present a completely new and annotated version of our checklist. For the first time, we list all bird subspecies known from Brazil that are currently accepted by at least one key ornithological reference work. The inclusion of the subspecies should be seen as a synthesis, and not as a taxonomic endorsement. As such, we include in the new checklist 1919 avian species, 910 of which are treated as polytypic in reference works (2042 subspecies), totaling 3051 taxa at the species and subspecies level. We anticipate that several of the subspecies included in our list may be subject to future taxonomic upgrades to species status, while others will probably be shown to be invalid in the light of future taxonomic studies. The results highlight Brazil as a megadiverse country and reinforce the need for proper enforcement of political tools, laws and international commitments assumed by the country to preserve its biodiversity.
Delayed maturity and low reproductive rate make raptors naturally sensitive to high mortality rates, yet a wide variety of human-related threats negatively affect their population dynamics and persistence over time. We modelled the variability in the proximate causes of mortality associated with six species of large migratory raptors characterized by different ecological traits. We tested the hypothesis that species-specific mortality signals occur owing to differential exposure to threats in space and time. We relied on an unprecedently large dataset of ring (band) recovery (31269 records) over a period of > 100 years. Our findings suggested that mortality of these birds has declined dramatically since the late 1970s. We found species-specific seasonal patterns of mortality, with higher mortality rates during early life-stages. For Black Kite, Common Buzzard, and Osprey, mortality increased with distance travelled and decreased with distance from migratory bottlenecks. Human-related mortality was higher than natural mortality (47% vs 5.6%), but after 1979 indirect anthropogenic factors increased, while direct ones decreased. Raptors showed differential specific exposure to mortality causes (direct human: Honey Buzzard, Marsh Harrier; indirect human: Common Buzzard, Black Kite; direct and indirect human: Osprey; natural: Montagu’s Harrier). Conservation efforts and international laws have helped lower mortality caused directly by humans, but new emerging human-related threats are impacting migratory raptors and call for advanced conservation efforts. In a fast-changing world, anticipating future threats is key to stemming losses and boosting future preservation.
In this study, we propose a novel strategy for identifying potential hotspots of avian roadkills in Europe. The proposed approach combines information about the spatial distribution of bird species at a comparatively higher risk of roadkill with data on road density. First, using a large dataset collected from several European studies and reports, we extracted the frequency of occurrence of bird casualties for 209 breeding bird species recorded in roadkill events. We standardized the relative frequency of roadkill from 0 (species never recorded in bird casualties' reports) to 1 (species with the higher number of roadkill's), obtaining a continuous variable that indicates the potential risk of roadkill species by species. Second, using published data on the spatial distribution of breeding bird species in Europe, we calculated the cumulative risk of roadkill in each bird assemblages, by considering the sum of the values estimated for each species in the previous step. Third, we calculated the road density in each spatial unit. Finally, we elaborate a forecasting map of potential avian roadkill-risk across Europe, by combining the data on road density and cumulative roadkill risk of bird communities. The tool proposed can help to identify potential hotspots at different spatial scales where the risk of avian roadkill is high, offering the possibility to improve conservation measures in road planning. Briefly, the prediction of where there is aligned convergence between communities with highly ranked species and landscapes with dense road networks can be used in procedures modelling wildlife-car collisions, for transportation mitigation projects.