Bird Strike Indicator/Bird Activity Monitor and Field Assessment of Avian Fatalities

Publication Number: 500-03-107F
Publication Date: October 2003

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Report Summary

Utilities, regulatory agencies, and environmental organizations are increasingly concerned about avian interactions with overhead power lines, communication towers, wind turbines, and other utility structures. Collisions and electrocutions kill birds and cause outages, but a lack of automated monitoring methods makes it impossible to quantify the problem or to evaluate possible mitigating measures. This interim report describes results to date of a project to develop automated monitors to gather information on bird strikes and evaluate the efficacy of mitigating devices such as line markers and flight diverters.

Results & Findings

Two different types of monitor are needed: a Bird Strike Indicator (BSI) and a Bird Activity Monitor (BAM). BSI is an impulse-based vibration sensing and recording tool to study bird collisions with aerial cables. BAM is an intelligent image-based sensing and recording tool to assist with detailed study of wildlife interactions with various types of structures. A Pre-Prototype BSI system, based on an earlier system developed by Pacific Gas & Electric, is complete; and its functional specifications are included in the report. The BAM is at an earlier stage of development.

To prepare for field testing of the new equipment and to develop an experimental design for testing the efficacy of mitigating measures, the BSI Project conducted dead bird surveys for two years at a North Dakota study site.

On-site testing of the BSI and BAM will take place at a transmission line segment that parallels U.S. Highway 83 between Lake Audubon and Lake Sakakawea in central North Dakota. This line segment has a history of bird collision problem; during one 3_month period in 1976 a total of 244 birds were found. The line segment is located on the western boundary of Audubon National Wildlife Refuge. Once fully evaluated, the BSI and BAM may provide cost effective alternatives to ground searches. After initial testing of BSI prototypes during the third year of baseline dead bird surveys, wires in a subset of spans at the study site will be marked to mitigate collisions.

Challenges & Objectives

Two primary goals of this project are to develop automated monitors to gather information on bird interactions that is difficult or impossible to obtain through direct human observation and to evaluate the efficacy of mitigating devices such as line markers and flight diverters.

Applications, Values & Use

New approaches to reducing interactions between birds and transmission and distribution structures, wind turbines, and communication towers can avoid outages, reduce costs, and enhance compliance with environmental regulations.

EPRI Perspective

EPRI has conducted two workshops on avian interactions with utility structures (EPRI reports TR-103268 and 1005180).

Approach

The project team began development of a prototype bird strike indicator with state of the art electronics and prepared to test the system in the laboratory and in actual field settings. The team initiated development of a bird activity monitor, and conducted dead bird surveys to document annual numbers and spatial distribution of avian fatalities at the North Dakota study site.

Keywords: Birds, Bird strike indicator (BSI), Bird activity monitor (BAM), Power lines, Overhead structures

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Table of Contents

1 Introduction..........1-1

2 Bird Strike Indicator..........2-1

3 Bird Activity Monitor..........3-1

4 Mitigating Bird Collisions with Power Lines..........4-1

5 Estimating Numbers of Birds Killed by Collision with Power Lines..........5-1

6 Results of Dead-Bird Searches in 2001 and 2002..........6-1

7 Literature Cited..........7-1

A) BSI Functional Specification..........A-1

B) List of TAG members..........

C) Causeway Dead-Bird Search Protocol..........C-1

D) Reference Guide for Classifying Cause of Death from Simple Necropsy..........D-1

E) Pothole Transect Search Protocol..........E-1

F) Bird Overflight Observations and Vehicle Counts..........F-1

 

List of Figures

Figure 1-1 Possible Attachment Locations for Bird Activity Monitor and Bird Strike Indicators and their Associated Ground Station..........1-2

Figure 2-1 PG&E Prototype Bird Strike Indicator..........2-2

Figure 2-2 Prototype BSI Sensor Components..........2-4

Figure 2-3 Accelerometers Selected for BSI..........2-5

Figure 2-4 Prototype BSI Sensor Circuit Board..........2-6

Figure 2-5 Analog Filter Frequency Response..........2-7

Figure 2-6 Typical Utilco Clamp Selected for Mounting BSI..........2-9

Figure 2-7 Prototype BSI Enclosure Mounted to the Utilco Clamp..........2-9

Figure 2-8 A Self Contained Brick Computer..........2-10

Figure 2-9 Enclosure Housing Brick Computer and Other Hardware for Base Station..........2-10

Figure 2-10 Power Supply Box for AC Powered Base Station..........2-11

Figure 2-11 Solar Power Supply for the Base Station..........2-12

Figure 5-1 View of Causeway from Meadow at Span 1, Looking at Span 2
(in foreground) with Towers Typical of those in Spans 2-12..........5-3

Figure 5-2 Aerial View (to Northwest) of Span 1 where Two 115 kV Lines Transition from Structures 12/5 at Left to Single Structure 12/6, just Visible at Right. The 41.6 kV Line Supported by Wood Poles Parallels the Highway and Transitions to Structure 12/6. Lake Audubon is in Foreground and Lake Sakakawea in Background..........5-3

Figure 5-3 Aerial View (to Northwest) of Span 13 showing Meadow, Tree Rows, and Pond East of Power Line. Single 115 kV Line Transitions from Vertical to Horizontal Orientation and 41.6 kV Line Transitions to Single Wood-pole Structures..........5-4

Figure 5-4 Aerial View (to Northwest) of Span 12 showing Irregular Topography and Subspans Resulting from Construction of the Substation. One 115 kV Line Terminates at the Substation..........5-5

Figure 5-5 Schematic of Causeway at Spans 2—11 Showing Five Transects Delineated for Dead Bird Searches. Railway-Ditch, Highway, and Dirt-Strip Transects are Also Common to Spans 1, 12, and 13. Locations of Dead Birds found at all Spans are Recorded Relative to South Tower in Span, and to Guardrail (GR)..........5-13

Figure 5-6 Schematic of Span 1 showing Meadow and Riprap Transect Lines (Dashed Lines). Dirt-strip (not shown) East of Guardrail (GR) is also a Walking Transect in Span 1. Eastern Boundary of Meadow Search Area Extends 164 ft (50 m) from the Outer Conductor. Meadow Transect Line Spacing shown in Meters..........5-15

Figure 5-7 Schematic of Span 12 Showing Riprap and Substation Perimeter Transects and Transect Lines through Small Woodlot at North End of Span (Dashed Lines). Dirt Strip (not shown) East of Guardrail (GR) and Gravel Road are also Walking Transects in Span 12..........5-15

Figure 5-8 Schematic of Span 13 Showing Meadow Transect Lines (Dashed Lines) with Spacing shown in Meters. Dirt Strip (not shown) East of Guardrail (GR) and Gravel Road are also Walking Transects in Span 13. Eastern Boundary of Meadow Search Area Extends 164-ft (50 m) from the Outer Conductor..........5-15

Figure 6-1 Temporal Patterns in Numbers of Dead Birds Collected at Survey Transects at Audubon Causeway Without Adjustment for Recovery Rates..........6-5

Figure 6-2 Spatial Patterns in Numbers of Dead Birds Collected at Survey Transects at Audubon Causeway without Adjustment for Recovery Rates..........6-6

Figure 6-3 Relationship Between Bird Length and Recovery Rate for High and Low Habitat-Related Visibility Classifications Based on Model 1 (blen, vis), and Proportion of Planted Birds Recovered with 95% Confidence Intervals Based on Data Grouped According to Table 6-5..........6-10

Figure 6-4 Relationship Between Bird Length and Recovery Rate for High and Low Habitat-Related Visibility Classifications Based on Model 2 (blen, vis, blen vis), and Proportion of Planted Birds Recovered with 95% Confidence Intervals Based on Data Grouped according to Table 6-5..........6-11

Figure 6-5 Relationship Between Bird Length and Recovery Rate for Habitat-Related Visibility Classifications Based on Model 3 (blen, tvis)..........6-11

Figure 6-6 Relationship Between Bird Length and Recovery Rate for High and Low Habitat-Related Visibility Classifications by Year Based on Model 4 (year, blen, vis)..........6-12

Figure 6-7 Relationship Between Bird Length and Recovery Rate for High and Low Habitat-Related Visibility Classifications by Span Type Based on Model 5 (stype, blen, vis)..........6-12

Figure 6-8 Temporal Distribution of Estimated Numbers of Dead Birds Occurring within Search Transects at Audubon Causeway, Based on Averaging Models 1 and 2..........6-13

Figure 6-9 Spatial Distribution of Estimated Numbers of Dead Birds Occurring within Search Transects at Audubon Causeway, Based on Averaging Models 1 and 2..........6-14

Figure 6-10 Spatial Distribution of Estimated Numbers of Dead Birds Occurring within Search Transects at Audubon Causeway, Based on Model 1, only (blenx vis model)..........6-14

List of Tables

Table 2-1 Comparison of Specifications for the Two Accelerometers..........

Table 5-1 Characteristics of Spans at the Transmission Line Segment at Audubon Causeway in Central North Dakota..........

Table 5-2 Pothole Transect Locations from Intersection of U.S. Highway 83 and State Highway 37..........

Table 6-1 Dead Birds found at Audubon Causeway (Total=451), 17 April—31 October 2001..........

Table 6-2 Dead Birds found at Audubon Causeway (Total=434), 17 April—31 October 2002..........

Table 6-3 Most Common Species Groups (>20 individuals) found at Audubon Causeway, 2001 and 2002..........

Table 6-4 Spatial Distribution of Birds Placed at Audubon Causeway for Estimating Recovery Rates..........

Table 6-5 Numbers of Birds Placed at Audubon Causeway for Estimating Recovery Rates. Classification of Bird Length shown here is Convenient for Summarization — Bird Length was treated as a Continuous Variable in Logistic Regression..........

Table 6-6 Logistic Regression Models Considered for Estimating Recovery Rate, Ranked by AIC_c..........

Table 6-7 Specification of Top Five Candidate Models. Coefficients are on Logit Scale..........

Table 6-8 Biases of Estimated Population Sizes from Equation 5-7 and Equation 5-16 (True Total N = 300) for Three Hypothetical Species with Different Probabilities of Recovery (r_s) and Numbers/Species (N_s) and Sampling Variance in Estimating r_s is Ignored..........

Table 6-9 Biases of Estimated Population Sizes from Equation 5-7 and Equation 5-16 (True Total N = 300) for Three Hypothetical Species with Different Probabilities of Recovery (r_s) and Numbers/Species (N_s), where Numbers of Planted Birds Recovered/Species is a Random Binomial Variate (for r_s, N_s)..........

Table F-1 Pothole Transect Sub-Transect Locations..........

Table F-2 Minimum Classification Level for Birds Flying Over Highway..........

Table F-3 Examples of Abbreviations, Species, and Species Groups - Others are Possible..........