Malfunction Rates of Bird Flight Diverters on Powerlines in the Mongolian Gobi

Abstract

The Oyu Tolgoi (OT) project, one of the world’s largest copper and gold mines, is
located in Gobi Desert of Mongolia. To help meet its target of Net Positive Impact
on key biodiversity features such as the Houbara bustard (Chlamydotis undulata)
the OT installed bird fl ight diverters (BFDs include spiral and fl apper devices) to
its power transmission lines to reduce the risk of birds hitting the wires. Despite
the many studies demonstrating that BFDs reduce collision rates, we could fi nd
no published information on malfunction rates of BFDs. In January 2013, we
surveyed the physical function of 1,200 BFDs (e.g. 600 fl appers and 600 spirals)
in three sample areas on each of four lines of varying voltage and structure. Of the
600 fl appers examined, 123 had malfunctioned within nine months of installation,
while the malfunction rate of the 600 spirals studied was zero. Using a Generalized
Linear Mixed Model, we found that the rate of fl apper malfunction increased with
decreasing fl apper size and power line diameter. Further, the fl apper malfunction
rate increased as the distance between poles increased. The cost of replacing
malfunctioning BFDs is very high as there are serious health and safety constraints
related to working with live wires. Factors aff ecting diverter malfunctioning need
to be considered for future powerline projects and our information can serve as
basis for developing national standards or regulations for powerline mitigation in
Mongolia.

Full text

13
© 2016 Journal compilation
http://mjbs.num.edu.mn
http://biotaxa.org./mjbs
Volume 14(1-2), 2016
Mongolian Journal of Biological
Sciences
ISSN 1684-3908 (print edition)
ISSN 2225-4994 (online edition)
MJBS
Original Ar• cle
http://dx.doi.org/10.22353/.....
Key words: Bird
! ight diverter, Gobi,
malfunction, mitigation,
powerline
Article information:
Received: 26 Feb. 2016
Accepted: 04 Nov. 2016
Published online:
14 Nov. 2016
Correspondence:
dashnyamb@ot.mn
Cite this paper as:
Malfunction Rates of Bird Flight Diverters on
Powerlines in the Mongolian Gobi
Batsuuri Dashnyam1*, Tsolmonjav Purevsuren1, Saruul Amarsaikhan1, Dandarmaa
Bataa1, Bayarbaatar Buuveibaatar2 and Guy Dutson3,4
1Health, Safety and Environment Department, Oyu Tolgoi LLC, Chingis Avenue 15,
Ulaanbaatar 14240, Mongolia
2Mongolia Program, Wildlife Conservation Society, Ulaanbaatar, Mongolia
3The Biodiversity Consultancy, 3E King’s Parade, Cambridge, CB2 1SJ, United Kingdom
4School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Vic 3216, Australia
Abstract
The Oyu Tolgoi (OT) project, one of the world’s largest copper and gold mines, is
located in Gobi Desert of Mongolia. To help meet its target of Net Positive Impact
on key biodiversity features such as the Houbara bustard (Chlamydotis undulata)
the OT installed bird ! ight diverters (BFDs include spiral and ! apper devices) to
its power transmission lines to reduce the risk of birds hitting the wires. Despite
the many studies demonstrating that BFDs reduce collision rates, we could " nd
no published information on malfunction rates of BFDs. In January 2013, we
surveyed the physical function of 1,200 BFDs (e.g. 600 ! appers and 600 spirals)
in three sample areas on each of four lines of varying voltage and structure. Of the
600 ! appers examined, 123 had malfunctioned within nine months of installation,
while the malfunction rate of the 600 spirals studied was zero. Using a Generalized
Linear Mixed Model, we found that the rate of ! apper malfunction increased with
decreasing ! apper size and power line diameter. Further, the ! apper malfunction
rate increased as the distance between poles increased. The cost of replacing
malfunctioning BFDs is very high as there are serious health and safety constraints
related to working with live wires. Factors a# ecting diverter malfunctioning need
to be considered for future powerline projects and our information can serve as
basis for developing national standards or regulations for powerline mitigation in
Mongolia.
Dashnyam, B., Purevsuren, Ts., Amarsaikhan, S., Bataa, D., Buuveibaatar, B., and
Dutson, G. 2016. Malfunction rates of bird ! ight diverters on powerlines in the
Mongolian gobi. Mong. J. Biol. Sci., 14(1-2): 13-20.
Introduction
The Oyu Tolgoi (OT) project, one of the
world’s largest copper and gold mines, is located
in Khanbogd soum in Umnugobi province of
Mongolia. In 2012, OT constructed a 96 km
220 kV power transmission line between the OT
mine site and the Gashuun Sukhait (GS) check
point at the Mongolia-China border. OT has
also constructed a 35.5 km 35 kV transmission
line from the mine site to Khanbogd town, a 68
km 35 kV line to the bore" eld at Gunii Hooloi
(GH), shorter 35 kV lines within the mine site
(LA), and 6.3 kV distribution lines to individual
production bores (PB) (Figure 1).
OT has a speci" c aim to achieve a Net
Positive Impact on key biodiversity features
in the Southern Gobi region, notably the

Dashnyam et al. Malfunction of bird ! ight diverters.
14
Asiatic wild ass (khulan in Mongolian; Equus
hemionus), Goitered gazelle (or Black-tailed
gazelle; Gazella subgutturosa) and Houbara
bustard (Chlamydotis undulata) (TBC & FFI,
2012). Some of the OT powelines cross the
Galba Gobi Important Bird Area that supports
a globally important population of Houbara
bustard (Batbayar & Natsagdorj, 2009; Batbayar
et al., 2011). The OT Environmental and Social
Impact Assessment predicted that collisions with
project power lines would signi" cantly impact
some bird species including the Houbara bustard,
as they are particularly susceptible to colliding
with power lines (Martin & Shaw, 2010).
Powerlines are estimated to kill 12-64
million birds each year in the USA (Loss et al.,
2014) and 2-26 million in Canada (Rioux et
al., 2013). Marking power lines with bird ! ight
diverters (BFDs) to increase the visibility of
these lines to ! ying birds has been shown to
reduce mortalities by 55–94% (Barrientos et al.,
2011). Common BFDs include spiral and ! apper
devices: Polyvinyl chloride (PVC) spirals, alone,
have been shown to reduce bird collisions by up
to 81% (Janss & Ferrer, 1998), while ! appers on
their own have been shown to reduce collisions
by 60-63% (Brown & Drewien, 1995; Yee,
2008), and ! appers added to spirals have been
shown to reduce collisions by an additional 52%
(Anderson, 2002).
During 2013, there were 118 recorded
incidents of birds colliding with the OT-GS
power transmission line, despite the installation
of BFDs. However, a signi" cant proportion of
! appers appeared to malfunction soon after the
installation. There is no published information
available on malfunction of BFDs. This study
aimed to identify causes of BFD malfunction,
and to recommend improved operating
procedures.
Study area
The OT study area is located in Khanbogd
soum in Umnugobi province, approximately
80 km north of the Mongolia-China border and
550 km south of Ulaanbaatar (Figure 1). The
climate is strongly continental with daily means
reaching 40oC in summer and dropping to -35oC
in winter. The long-term average (1976–2014)
wind speed around OT is 4.2 m.sec-1, with the
strongest wind recorded being 49.9 m.sec-1 in
June 2007 (Oyu Tolgoi General Site Conditions
report, 2015). Elevations in the study area range
from 600-1350 m. Vegetation is sparse and
in large parts dominated by drought adapted
central Asian desert species, particularly Stipa
gobica, Allium mongolicum, Iljina regelii, and
Anabasis brevifolia (von Wehrden et al., 2009).
To date, 225 species of birds have been recorded
in and around the OT mine site. Several globally
and regionally threatened species found at the
site include endangered Dalmatian pelican
Figure 1. Study area in the southern Gobi, Mongolia, showing the location of power lines and study sites.

15
Mongolian Journal of Biological Sciences 2016 Vol. 14 (1-2)
(Pelecanus crispus), Relict gull (Larus relictus)
and Great bustard (Otis tarda) and, in addition
to these species, Saker falcon (Falco cherrug),
Houbara bustard (Chlamydotis undulata),
Short-toed snake eagle (Circaetus gallicus) and
Amur falcon (Falco amurensis) do also occur
(Purevsuren et al., 2013).
Materials and Methods
To mitigate the impacts of power lines, BFDs
were installed in April and May 2012 at 10 m
intervals along the OT-GS power transmission
line, alternating between BirdMark™, hereafter
called ‘! appers’ (Clydesdale Ltd, Kempston,
Bedford, United Kingdom), and Swan-Flight
Diverter™, hereafter called ‘spirals’ (Ampirical
Solution LLC, Mandeville, Louisiana State,
USA) (Figure 2A). Two sizes of ! apper were
installed – small ! appers were designed to " t
wires of 6-16 mm diameter and large ! appers
to " t wires of 16-70 mm diameter. This is the
" rst time that BFDs have been installed in
Mongolia. Flappers were designed to rotate,
! ap, and whistle in response to wind and wire
movement, to re! ect light, and to glow for up to
10 hours after the sun has set (Figure 2B). Spirals
were designed to be highly visible but immobile
Figure 2. Schematic of the installation pattern of Bird Flight Diverters (A) and photos of a ! apper (B) and a
spiral (C) installed on power line in Southern Gobi, Mongolia.
(A)
(C)(B)

Dashnyam et al. Malfunction of bird ! ight diverters.
16
(Figure 2C). Both types of BFDs were installed
on the highest wire because the majority of
collisions are with these earth wires, which are
higher, thinner, and in a single row (e.g. APLIC,
2006).
In January 2013, we surveyed the physical
function of 600 ! appers and 600 spirals in three
sample areas, each containing 100 BFDs (e.g. 50
! appers and 50 spirals), on each of four lines:
the OT – GS 220 kV transmission power line
(GS), OT – GH 35 kV transmission power line
(GH), 35 kV power lines inside the OT site area
(LA) and 6.3 kV power distribution lines (PB)
(Figure 1). Each sample area was spaced 1 km
apart on the GS and GH lines, but the samples
were continuous on the shorter LA and PB lines.
We walked along the sample areas, and observed
each ! apper with 10x42 binoculars to determine
whether it was properly working (e.g., rotating
and ! apping), and photographed it with a Canon
7D camera and 100-400 mm lens. We considered
! appers to have malfunctioned when stuck in the
up position and immobile, or when fallen. We
also considered spirals to have malfunctioned
when fallen. To explore potential causes of
malfunction, we measured the distance between
adjacent pylons or poles, the distance from each
BFD to the nearest pylon or pole, and the height
of each BFD from the ground using a Swarovski
10 x 30 laser range" nder. We also recorded the
elevation (above sea level) of each BFD using a
Global Positioning System.
We used General Linear Mixed Models
(GLMMs) to model the combined e# ects of the
six variables on physical function of ! appers:
the distance between adjacent poles (Pole-pole),
the distance from each BFD to the nearest pole
(Flap-pole), the height of each BFD from the
ground (Height), elevation (Elevation), ! apper
size (Size), and the wire diameter (Diameter).
We " tted GLMMs with a binomial error
distribution to the data using the ‘lme4’ library
in R (R Development Core Team, 2008). We
excluded Height from the model because it was
positively correlated with Flap-pole (rho = 0.93)
and Elevation (rho = 0.72). We scaled each
continuous predictor variables using ‘z-score’
standardization to have a mean of 0 and a
standard deviation of 1. We incorporated site
(e.g. GS, GH, LA, and PB) as a random factor in
the analysis to account for potential di# erences
in topography. We ran all possible model subsets
of the " ve variables and ranked them using
the Akaike Information Criterion (AICc) for
small sample sizes. The " nal set of models was
the most parsimonious based on $AICc < 4
(Anderson, 2008). Models with a ≤ 2 AICc unit
diff erence were considered equivalent (Burnham
& Anderson, 2002). To quantify the infl uence
of each covariate on diverter function, we used
model-averaging techniques to obtain parameter
estimates, unconditional standard errors and the
relative support of each variable (Burnham &
Anderson, 2002) within the ‘MuMIn’ library in
Site GS GH LA PB Total
Voltage (kV) 220 35 35 6.3
Diameter (mm) 16 10.5 10.5 18.9
No. spirals
studied*
150 150 150 150 600
No. fl appers
studied
(large: small)
150
(0:150)
150
(5:145)
150
(142:8)
150
(77:73)
600 (224:376)
No. fl appers
malfunctioned
(large: small)
39
(0:39)
51
(1:50)
22
(19:3)
11
(6:5)
123
(26:97)
% large fl appers
malfunctioned
-
-
20%
(1/5)
13%
(19/142)
8%
(6/77)
12%
(26/224)
% small fl appers
malfunctioned
26%
(39/150)
34%
(50/145)
38%
(3/8)
7%
(5/73)
26%
(97/376)
Table 1. Number of fl appers and spirals studied and percent of those that malfunctioned on four power transmission
lines (GS = Gashuun Sukhait, GH = Gunii Hooloi, LA = OT mine site, and PB = Production bores) of varying
voltage and diameter in the Southern Gobi, Mongolia. * The malfunction rate of the spirals studied was zero.

17
Mongolian Journal of Biological Sciences 2016 Vol. 14 (1-2)
R (Barton, 2012). In addition, we calculated the
model AICc weights to measure the likelihood
of a candidate model being the best among the
set of fi tted models. We acknowledge that these
modelling approaches are post-hoc analyses and
no manipulations or fi eld experiments was made.
Results
We surveyed a total of 600 fl appers (376
small and 224 large) in four sites, of which 123
had malfunctioned (97 small and 26 large; Table
1). Whereas, the malfunction rate of 600 spirals
examined in the four power transmission lines
of varying voltage and diameter was zero. The
parameter estimates of full model indicated
strong infl uence of covariates such as Size,
Diameter, and Pole-pole on the malfunction
rate of fl appers (Table 2). The probability of the
fl apper malfunction increased as the size of the
device (β = -1.134, SE = 0.304) and the diameter
of the wire decreased (β = -0.727, SE = 0.270),
while the fl apper malfunction rate increased as
the distance between poles increased (β = 0.482,
SE = 0.233; Table 2). However, Elevation and
Flap-pole appeared as weak predictors given
that the estimated coeffi cients of these covariates
overlapped zero (Table 2). The estimated
variance of the random eff ect (e.g. site) was
nearly zero, suggesting site-specifi c diff erences
Coeffi cients Estimate SE Z value P value Variable
importance
Intercept -1.103 0.141 -7.847 <0.001
Size -1.134 0.304 -3.730 <0.001 1.00
Diameter -0.727 0.270 -2.694 <0.005 1.00
Pole-pole 0.482 0.233 2.066 <0.05 0.81
Elevation -0.402 0.357 -1.124 NS 0.39
Flap-pole -0.033 0.131 -0.250 NS 0.28
Table 2. Model averaged-parameter estimates of the full model for determining physical function of bird
fl ight diverters installed on powerlines in Southern Gobi, Mongolia. All variables were scaled using ‘z-score’
standardization. Coeffi cient estimates, standard errors and relative importance of variables were obtained based on
the Akaike Information Criterion for small samples sizes (AICc) statistic following Burnham & Anderson (2002)
model averaging procedures. NS – not signifi cant.
Table 3. Model selection results for estimation of factors aff ecting malfunction rate of bird fl ight diverters installed
on powerlines in the Southern Gobi, Mongolia. We present results of the top 7 ranked models that have AICc
weight > 0.05.
Rank Model structure LogLik AICc ΔAICc Weights
1Size + Pole-pole + Diameter -283.980 578.1 0.00 0.345
2Size + Pole-pole + Diameter + Elevation -283.304 578.8 0.60 0.244
3Size + Pole-pole + Diameter + Flap-pole -283.961 580.1 2.00 0.127
4 Size + Pole-pole + Diameter + Elevation + Flap-
pole -283.273 580.7 2.67 0.091
5Size + Diameter -286.457 581.0 2.92 0.080
6Size + Diameter + Flap-pole -285.675 581.5 3.39 0.063
7Size + Diameter + Elevation -285.905 581.9 3.85 0.050
LogLik = log likelihood; AICc = corrected Akaike information criterion; ΔAICc = diff erence between model
AICc and the minimum AICc; weights = model AICc weight.

Dashnyam et al. Malfunction of bird ! ight diverters.
18
in malfunction rate of the ! appers was negligible.
When running all possible subset models, the
model of ! apper malfunction rates that best " t
our data (minimum AICc) contained covariates
of Size, Diameter, and Pole-pole (Table 3). The
inclusion of the Elevation into the best model
produced the second ranked competitive model
(AICc weight 24%). These parameters accounted
for 59% of the AICc weight among the seven
models (Table 3). We found slight changes in
the parameter estimates from the top ranked two
competitive models, relative to the parameter
estimates from the full model (Table 2 and 4).
Based on the hierarchical partitioning approach,
the relative importance of Diameter, Size, and
Pole-pole were greater than those of Elevation
and Flap-pole for explaining physical function of
! apper performance (Table 2).
Discussion
This is the " rst e# ort to examine factors
in! uencing performance of BFDs in Mongolia,
and the " rst published study we could " nd to
evaluate BFD malfunction rates. We found that
123 of 600 ! appers had malfunctioned within
nine months of installation. During subsequent
monitoring we found that the malfunction rate
increased with time. In contrast, none of 600
spirals studied along the four power transmission
lines of varying voltage and diameter was
malfunctioned. This is probably due to the spirals
were designed and installed to be immobile.
When modelled, we found physical function
of ! apper failed as the size of the device and
the diameter of the wire decreased, while the
! apper malfunction rate increased as the distance
between poles increased. However, elevation
and the distance from each ! apper to the nearest
pole appeared as weak predictors in! uencing
malfunction of ! appers.
The causes of these malfunctions of the
! appers are not known but likely related to the
design of the grounder that connects the ! apper
to the wire and/or to the wire ring that allows
the ! appers to rotate and ! ap with wind and
wire movement. Some small ! appers (designed
for 35 kV lines) might have been incorrectly
installed on unsuitably large 220 kV lines. High
wind speeds might have caused swinging and
twisting of wires which locked ! appers into " xed
positions, and/or wore through the wire rings,
and/or dislodged or damaged the grounders.
Additionally, sub-zero temperatures and
encrusted ice might have damaged the wire rings,
grounders or other parts of the ! appers.
The cost of replacing malfunctioning BFDs
is now very high because of health and safety
constraints related to working with live wires.
There are two ‘lessons learned’ arising from
this research as the " rst e# ort to mitigate the
impacts on birds of power lines in Mongolia.
First, this study acts as a cautionary warning to
the “national power transmission grid” state
owned company, other mining companies, and
power line installers about the high rate of BFD
malfunction (e.g. ! appers), possibly related
to the weather conditions of the South Gobi.
Secondly, our experience with the installation
of BFDs should be incorporated into national
standards, speci" cally MNS 2919: 2003, MNS
5350: 2003 (Mongolian National Standard,
2004 and 2016), and power construction and
regulations for the mitigation of powerline
impacts on birds (Ministry of Infrastructure of
Mongolia, 2004).
Electric power supply networks in Mongolia
are responsible for causing bird mortality,
especially raptors, through electrocution and
collision (Amartuvshin & Gombobaatar 2012).
We recommend that future power lines installed
in Mongolia in areas of high risk to threatened
birds, such as bustards, include spirals as BFDs
because their malfunction rate was zero. Flappers
Table 4. Model-averaged estimates and standard errors (β ± SE) of the top ranked 2 competitive models (e.g.
'AICc value is within 2 AICc) for determining physical function of bird ! ight diverters installed on powerlines in
Southern Gobi, Mongolia. Signi" cance code: ‘***’ 0.001; ‘**’ 0.01; ‘*’ 0.05; ‘.’ 0.1.
Rank Intercept Size Pole-pole Diameter Elevation
1 -1.160 ± 0.133*** -0.962 ± 0.264*** 0.266 ± 0.120* -0.462 ± 0.122***
2 -1.103 ± 0.140*** -1.133 ± 0.304*** 0.456 ± 0.209* -0.726 ± 0.269** -0.397 ± 0.356.

19
Mongolian Journal of Biological Sciences 2016 Vol. 14 (1-2)
should be installed on an experimental basis to
investigate their durability and their effi cacy
as BFDs. More importantly, where possible,
projects and developers should design-out the
need for power lines, or minimise their length
and locate them along routes of minimum
risk to threatened birds. Lower-risk designs of
pylons, poles and wire arrays should always be
chosen to permanently reduce the risk to both
threatened birds and the installer’s reputation.
This is particularly topical in the South Gobi, as
new powerlines are being constructed in areas
supporting Houbara bustards and other species of
conservation concern.
Acknowledgements
Oyu Tolgoi LLC provided support for this
study. We thank Dennis Hosack, Jez Bird,
John Pilgrim, David Wilson, and Oyun-Erdene
Tseesuren for their advice, comments, and
assistance on the survey.
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