R0115-027 Draft Golden Eagle Final Summary Report.doc

DRAFT

FINAL SUMMARY REPORT

FOR GOLDEN EAGLE ACTIVITY ON AIR FORCE RANGES

IN THE WESTERN UNITED STATES

Prepared for:

Air Force Civil Engineer Center

Mr. Kevin Porteck, Natural Resources SME

2261 Hughes Avenue, Suite 155

Lackland Air Force Base, Texas 78236-9853

Prepared by:

AMEC Environment & Infrastructure, Inc.

9210 Sky Park Court, Suite 200

San Diego, California 92123

Under contract to:

U.S. Army Corps of Engineers

Fort Worth District

Mr. Jack Mobley, Contracting Officer’s Representative

819 Taylor Street, RM 2A17

Fort Worth, Texas 76102-0300 Contract No. W9126G-14-C-0034 AMEC Project No. 912640003

TABLE OF CONTENTS

Page ivACRONYMS AND ABBREVIATIONS

1-11.0

INTRODUCTION

1-11.1 Study Need and Purpose

1-21.2 Study Location

1-31.3 Project Objectives

2-12.0

METHODS

2-12.1 Historical Data Acquisition

2-22.2 Telemetry for Eagle Habitat Use, Activities, Movements, and Risk Analysis

2-22.2.1 Trapping Methods

2-52.2.2 Handling and Transmitter Attachment

2-92.2.3 Transmitter Systems

2-112.2.4 Telemetry Data Analysis

2-112.3 Nesting Surveys

2-112.3.1 Aerial Surveys

2-132.3.2 Ground-Based Surveys

2-142.3.3 Occupancy and Productivity

2-142.4 Prey Analysis

2-152.5 Bait Stations

2-162.6 Point Counts

3-13.0

RESULTS

3-13.1 Summary of Transmitters Deployed

3-13.1.1 Transmitters Deployed in 2013

3-13.1.2 Transmitters Deployed on Adults in 2014

3-23.1.3 Transmitters Deployed on Nestlings in 2014

3-33.2 Saylor Creek Range and Juniper Butte Range

3-33.2.1 Telemetry

3-53.2.2 Nest Surveys

3-63.2.3

3-73.2.4 Prey Item Analysis

3-123.3 Utah Test and Training Range

3-123.3.1

3-143.3.2

3-153.3.3

3-163.3.4

3-213.4 Nevada Test and Training Range

3-213.4.1

3-243.4.2

3-253.4.3

3-263.5 Melrose Air Force Range

3-263.5.1

3-263.5.2 Aerial Nest Surveys

3-273.5.3 Point Count Surveys

TABLE OF CONTENTS (Cont.)

Page

4-14.0

SUMMARY AND CONCLUSIONS

4-14.1 Saylor Creek Range/Juniper Butte Range

4-14.1.1 Nesting and Productivity

4-14.1.2

4-14.1.3

4-14.1.4

4-24.1.5 Conclusions

4-24.2 Utah Test and Training Range

4-24.2.1

4-24.2.2

4-34.2.3

4-34.2.4

4-34.2.5

4-34.3 Nevada Test and Training Range

4-34.3.1

4-44.3.2

4-44.3.3

4-44.3.4

4-54.4 Melrose Range

5-15.0

RECOMMENDATIONS

6-16.0

REFERENCES

LIST OF TABLES

2-12Table 2-1.

Summary of Aerial Survey Days

3-1Table 3-1.

Summary of Transmitters Deployed on Golden Eagles in 2013

3-2Table 3-2.

Summary of Transmitters Deployed on Adult Golden Eagles in 2014

3-3Table 3-3.

Summary of Transmitters Deployed on Nestling Golden Eagles in 2014

3-5Table 3-4.

Synopsis of Idaho 2014 GOEA Survey Results

3-8Table 3-5.

SCR/JBR Bait Station Summary May-Sept 2013

3-9Table 3-6.

SCR/JBR Bait Station Summary Sept 2013-May 2014

3-10Table 3-7.

3-16Table 3-8.

Synopsis of UTTR 2013 GOEA Survey Results

3-17Table 3-9.

Synopsis of UTTR 2014 GOEA Survey Results

3-19Table 3-10.

UTTR Bait Station Summary May 2013-September 2013

3-20Table 3-11.

UTTR Bait Station Summary September 2013- April 2014

3-24Table 3-12.

Synopsis of NTTR 2014 GOEA Survey Results

3-26Table 3-13.

NTTR Bait Station Summary July 2013- December 2013

3-27Table 3-14.

Golden Eagles Observed During MAFR Transect and Point Count Surveys

TABLE OF CONTENTS (Cont.)

LIST OF APPENDICES

Appendix A

FIGURES

Appendix B

STATE AND FEDERAL PERMITS

Appendix C

BAIT STATION PROTOCOL

Appendix D

CAPTURE FORMS

Appendix E

2013 PHOTOS

Appendix F

2014 PHOTOS

Appendix G

ALTITUDE GRAPHS

Appendix H

RECOVERY INFORMATION

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ACRONYMS AND ABBREVIATIONS

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1.0 INTRODUCTION

This report provides a final summary of data collected during the two-year span of golden eagle studies at five United States (U.S.) Air Force (AF) ranges in the western U.S. AMEC Environment & Infrastructure, Inc. (AMEC) conducted this two-year study on behalf of the Air Force Civil Engineer Center (AFCEC) under contract to the U.S. Army Corps of Engineers (USACE). This work was conducted in accordance with the January 2013 Technical and Management Work Plan (Work Plan) prepared by AMEC, and this report fulfills a performance requirement (Data Analysis and Summary Report) under USACE contract W9126G-14-C-0034. Prior to initiation of field studies, the Work Plan was approved by each AF Base (AFB), AFCEC, and Brian Millsap of the U.S. Fish and Wildlife Service (USFWS). This report includes a summary and final data analysis for data collected from February 2013 through October 2014. All map figures referred to in this report are provided in Appendix A.

1.1 Study Need and Purpose

Golden eagle (Aquila chrysaetos) populations may be declining throughout much of their range. Habitat loss that results from a wide array of land use changes often conflicts with the ecological requirements necessary to support viable nesting populations. Recent studies in the intermountain west indicate steady declines in golden eagle numbers (Kochert and Steenhoff 2002, Hoffman and Smith 2003, Good et al. 2007). The cause of these declines is believed to be associated with habitat loss due to human activities that result in large-scale land/habitat conversions. These changes may eliminate nesting habitat, which often includes the availability of required prey resources needed to successfully fledge offspring. These changes may also result from subtle but significant levels of human activity and disturbance to eagles near nesting locations which, over time, cause nesting sites with long histories of use to become permanently abandoned even though the nesting substrate remains seemingly intact. Land use changes, including those related to drought cycles, may also negatively affect local eagle prey populations, thus disrupting longstanding eagle nesting in certain areas.

AF training ranges in the western U.S. may provide large areas of foraging habitat and important nesting sites for golden eagles. In order to comply with the Bald and Golden Eagle Protection Act as codified in 16 U.S.C. 668-668c , the AF seeks to collect field data on golden eagle activity on these ranges sufficient to develop site-specific conservation measures and guidelines for compliance. This requires collection and analysis of data on golden eagle populations on ranges by season, recording of nesting activity and nest productivity, and information on daily activities, especially habitat use and flight patterns, of golden eagles in the area of AF mission activities.

The AMEC team has completed two field study seasons per Work Plan objectives, the results of which are presented in this final summary report. This information can be used to develop reasonable and credible conservation measures for incorporation into the Integrated Natural Resources Management Plans for each AF installation. The final summary report also provides data and results suitable for developing a Golden Eagle Conservation Plan should an application for a take permit be necessary.

1.2 Study Location

Data is provided from field activities carried out at the following AF ranges: Nevada Test and Training Range (NTTR) and adjacent Military Operations Areas (MOAs), Utah Test and Training Range (UTTR), Juniper Butte Range (JBR), Saylor Creek Range (SCR), and Melrose Air Force Range (MAFR). The location of each of the ranges within the western U.S. is shown in Figure 1‑1. The project study areas include each training range and its associated air space. Range boundaries and Restricted Air Space limits are shown on Figures 1-2a through 1-2d. AFBs associated with each range are identified and described below.

Mountain Home AFB, Idaho

· SCR is a 109,400-acre range located 12 miles southeast of Bruneau, in southeastern Idaho in the Bruneau Desert of Owyhee County. The range is east of the Bruneau River. SCR topography varies from flat and rolling buttes and ridgelines, with the dominant vegetation consisting of sagebrush.

· JBR is a 12,000-acre range located 37 miles southeast of Bruneau in the Inside Desert of Owyhee County, in the vicinity of Clover Creek, accessed by Clover-Three Creek Road. JBR topography varies from river gorges to open desert, with the vegetation consisting of sagebrush or riparian areas.

Nellis AFB, Nevada

· NTTR occupies 4,687-square miles (2.9 million acres) of southern Nevada and extends from south of Tonopah to about 40 miles north of Las Vegas, spanning Nye, Lincoln, and Clark counties.

· NTTR’s North Range lies primarily within the Great Basin Desert, while the ecology of NTTR’s South Range is more representative of the northern Mojave Desert.

Cannon AFB, New Mexico

· MAFR is a 60,000-acre range located in eastern New Mexico, about 25 miles west of Cannon AFB outside of Clovis, in Curry and Roosevelt counties. The range is about 3 miles south of U.S. Route 84/60. Shortgrass prairie is the dominant plant community. The range is relatively flat with the exception of several drainages, small canyons, and a minor amount of topographic relief associated with an unnamed mesa.

Hill AFB, Utah

· UTTR North encompasses 370,000 acres and is located about 80 miles west of Salt Lake City, in western Utah, in Boxelder and Tooele counties. It is within habitats typical of the Great Salt Lake Desert bordered by the Great Salt Lake to the east, and is about 20 miles north of Interstate 80 (I-80).

· UTTR South encompasses 590,000 acres and is located about 80 miles west of Salt Lake City, in Tooele County, about 10 miles south of I-80 in the Great Salt Lake Desert.

1.3 Project Objectives

The project objectives below were presented by the AF in their Statement of Objectives dated August 1, 2012. Ongoing studies at each range and in their vicinities contribute to addressing these objectives, which are summarized below. The following objectives have been met for the 2013 and 2014 field seasons:

1. Acquired census data for JBR, SCR, MAFR, NTTR, and UTTR to estimate the population of golden eagles for wintering, migration, and nesting season for breeding and non-breeding golden eagles. To date, survey data has been completed to cover both of the two consecutive breeding and migratory seasons. Breeding season surveys were timed early enough to note courtship and nest defense behavior.

2. Acquired data on daily flight patterns and habitat use by golden eagles on selected AF ranges during 2013 and 2014. Geospatial data on flight patterns of golden eagles were being collected on AF ranges by area, time of day, and altitude that is sufficient to determine potential conflicts between golden eagles and military overflights and range use during 2013 and 2014. Diurnal flight patterns of golden eagles were evaluated at SCR, JBR, and UTTR and have been evaluated in areas adjacent to NTTR. Golden eagle territories and home ranges have been estimated using geospatial data on eagle locations and habitat use. Data were collected sufficient to establish baseline populations, risk analysis and characterization, and other essential information to develop a Golden Eagle Conservation Plan should an application for a take permit be necessary.

3. Golden eagle nest site locations and nest occupancy were documented for the 2013 and 2014 breeding seasons on JBR, SCR, MAFR, NTTR, and UTTR. Geospatial data is provided on these nest locations. Number of golden eagle progeny and fledgling success rate was recorded for both nesting seasons.

4. A preliminary evaluation of the golden eagle prey base for each range has been conducted based upon research literature, interviews with local wildlife biologists, and direct observations made during the study.

5. A complete Summary Report presenting all data collection protocols, statistical analysis methods, results, and conclusions of the 2013 and 2014 field studies is provided herein. The Summary Report includes an analysis of the potential for conflicts between military activities and golden eagles for each range studied. Additionally, the Summary Report includes suggested management guidelines and conservation measures that can be used at all military ranges in the western U.S. This report serves to fulfill this project objective.

2.0 METHODS

In order to best evaluate seasonal golden eagle populations and habitat use at each of the AF Ranges, we applied a multi-level approach to data acquisition and analysis. Our study comprised the following methodologies which are described in this section:

· Historical data acquisition and analysis

· Attachment of GPS transmitters to eagles and analysis of telemetry data

· Nesting season surveys for occupancy and productivity

· Prey item analysis

· Baited remote camera stations

· Roadside transect/point count surveys

2.1 Historical Data Acquisition

AMEC conducted a comprehensive historical nest site record search to collect and digitally compile historically known and recently found locations of golden eagle nests within, or close to, the ranges. Data from ongoing golden eagle studies or incidental observations from each range were gathered to focus our study approach and provide the study foundation. Kickoff meetings were held with Natural Resources Managers for each range in October and November 2012 to review existing data and ongoing golden eagle survey programs. Additionally AMEC completed a search of all publicly available databases and resource agency records, plus any available records from public or private sources including the results of more recent helicopter/ground surveys that were conducted in the region of each range. AMEC contacted a variety of reliable and knowledgeable sources for golden eagle nesting information including the USFWS, HawkWatch, and state wildlife agencies such as Nevada Department of Wildlife (NDOW). We acquired any available golden eagle nesting survey data developed as a result of any previous golden eagle surveys. These locations were entered into our central nest locations database using Microsoft Excel software. The individual nest location records were made as complete as possible in terms of attribute data, locations, years of occupancy, etc. with their coordinates uploaded into Global Positioning System (GPS) units for easy reference during subsequent field surveys. All of these locational and attribute data have been linked into a centralized Geographic Information System (GIS) database for spatial analyses and data presentation and mapping in this final Summary Report.

GIS analysis of the survey areas was completed to best identify suitable potential golden eagle nesting habitat on the ranges. This analysis enabled the team to narrow the geographical focus of the field and aerial surveys to what was determined to be known and/or suitable nesting habitat, thus focusing the level of effort. We applied a simplified species distribution model approach to the total study area. The GIS team analyzed three basic variables likely to support golden eagle nests:

· degree of slope

· topographical relief and effective height

· habitat type(s).

The resulting area was compared with favorable characteristics to all range areas. These data combined with a helicopter site reconnaissance of each range conducted between November 2012 and January 2013 helped determine how to best census the ranges for nesting golden eagles and identify where suitable winter foraging habitat was likely to occur. Portions of the study areas that are the subject of ongoing eagle nest surveys and monitoring under separate contracts were removed from our survey area during this exercise. The combined results of the 2013–2014 data collection are presented here in the final Summary Report.

2.2 Telemetry for Eagle Habitat Use, Activities, Movements, and Risk Analysis

Telemetry is the remote collection and transmission of data and, in this study, involves trapping and attaching transmitters to a mix of resident golden eagles, fledgling or sub-adult eagles, and wintering eagles. It offers the advantage of collecting an enormous amount of important and otherwise unobtainable data on golden eagle habitat use. These data include location, altitude, speed, and heading and are used to track flight patterns and regional movements. Habitat utilization or other ecological information can be inferred from this data, and should an eagle die, the remains can be recovered and examined for sources of mortality. Telemetry is the only way to accurately collect data on golden eagle daily flight patterns including geospatial data on eagle locations and habitat utilization. During development of the Work Plan, it was determined to be the most effective way to identify and analyze potential risks and conflicts with AF activities. Compared to conducting field surveys, telemetry is extremely cost effective in terms of the amount of data collected. Telemetry continuously provided data throughout the life of the project. The USFWS and local AF bases have assumed responsibility for collection of telemetry data beyond the duration of this contract.

2.2.1 Trapping Methods

Based on the review of existing data, site reconnaissance results, and base approvals, the focus of trapping and telemetry efforts in 2013 occurred at UTTR, SCR, and JBR. Trapping efforts in 2014 were focused at NTTR and additional priority areas at UTTR. Brian Latta and Gregg Doney of BioResource Consultants (BRC) led eagle trapping efforts. Mr. Latta and Mr. Doney obtained all necessary state and federal permits for eagle trapping and transmitter attachment prior to trapping efforts; all relevant permits are provided in Attachment B. Trapping of adults/subadults was conducted in late February/early March at the Utah and Idaho ranges just prior to the critical time when birds are on nests and winter weather conditions allowed. Additional adult/subadult trapping efforts were conducted in June once chicks were a minimum of three weeks old. On lands adjacent to NTTR, transmitters were placed on 7-8-week old chicks in May/June 2014 via nest climbs.

With the exception of chicks, trapping methods employed use of radio-controlled bownets. Radio-controlled bownets are used to selectively capture large raptors such as bald and golden eagles. The bownet used for this study is 1.9 meters in diameter and can be remotely triggered from a distance of up to 800 meters (Jackman et al. 1994). It is composed of a hinged hoop with a net stretched loosely across and secured around the perimeter of the hoop. The hoop has two components: the stationary frame and the bow. The stationary frame is comprised of a metal channel, 8 centimeters (cm) wide x 8 cm deep, in the shape of a semi-circle or arc. The arc is bridged by a tubular shaft that holds the springs that power the bow. A crosspiece from the center of the arc to the center of the tubular shaft adds rigidity. The bow is made of 1.6 cm in diameter aluminum tubing bent into an arc and padded with foam pipe insulation. The bow is hinged to the stationary frame and, when set, is folded along with the net back into the channel and secured with the trigger. The radio-controlled trigger consists of a model airplane or car radio-control system (transmitter, receiver, servo, and power source) modified to activate an archery release (trigger), which holds the bow in place until the trap is set off. The receiver, servo, power source, and archery release are mounted in a waterproof case and attached to the bow through a hole in the top of the arc of the channel.

Bownet in open position

The whole unit is then buried at ground level and camouflaged so that only the antenna wire from the trigger is above ground. Bait is then secured to the center of the tubular shaft. The trap is placed at a site frequented by the target bird in a relatively open area that can be viewed from above, usually a grassy slope. The trap is usually installed and set prior to dawn to prevent eagles from seeing the trap placement. Bait used for trapping golden eagles is either carrion (e.g., dead jackrabbit or deer leg) or live (domestic rabbit). Typically a domestic rabbit is used in this study. The trap is observed from a blind or a vehicle at a distance of 50 to 800 meters using a spotting scope. When the target bird is feeding on the bait and the researcher is certain that the bird is centered in the trap, the bownet is triggered by toggling a lever on the transmitter. The transmitter sends a signal to the receiver that turns the servo, pulling the trigger on the archery release that releases the bow. When triggered, the bow pulls the net up and over the target bird, safely encircling it. The radio-control systems operate on radio frequency bands of 27 Megahertz (MHz), 72 MHz, and 2.4 gigahertz.

Bownet placed in open position with bait for trapping

In order to attach transmitter backpacks to nestling golden eagles, a two-man climbing team hikes to the top of the cliff directly above the subject eagle nest. The climbers rig a self-equalizing anchor system using one inch tubular nylon webbing and a combination of oval and locking carabiners, using standard rock-climbing methods of tying off to natural terrain features (i.e. boulders), using rock-climbing protection devices (e.g., pitons, chocks, camming-devices), or 24-inch steel construction stakes driven into the ground with a mallet. The self-equalizing anchor utilizes three or more anchor points and distributes the weight of the climber and ropes evenly, minimizing the strain on each anchor. Two 11-mm static climbing ropes are attached to the self-equalizing anchor. Depending on the height and topography of the cliff, these ropes are either long enough to reach the base of the cliff or long enough to reach just past the nest. A climber/biologist rappels down to the nest. The second climber monitors the anchor system in case the primary climber needs assistance. During the rappel the climber carefully cleans the route (removes loose rocks) so that the ropes will not dislodge any rocks during the ascent from the nest. A second two-man team vocally directs the climber to the nest from below and stands by in case a chick were to fledge prematurely in which case they could retrieve it. Once at the nest, the climber secures the chick(s) by wrapping their feet in Vetwrap and placing them in a padded, ventilated duffel bag. They then either rappels to the bottom of the cliff or ascends the ropes using mechanical ascenders with the chicks. Once the climber is safely off-rope measurements and blood and feather samples are taken from the chick(s) and the transmitter backpack attached as described below. The climber then re-accesses the nest and returns the chicks. The climber then leaves the nest, and the climbing team will pulls up the ropes, dismantles the anchor system, and hikes back to the vehicles.

Biologist repelling into nest to retrieve chick for transmitter attachment

2.2.2 Handling and Transmitter Attachment

The methods described below were used to handle captured eagles and outfit them with transmitter units. Given that the capture offers a rare opportunity to collect individual data, standard measurements and blood samples for pesticide and deoxyribonucleic acid (DNA) analysis were also taken from each bird. Eagles were also banded according to U.S. Geological Survey (USGS) Bird Banding Lab protocols.

2.2.2.1 Securing

1. Hoods: The most important stimulus to raptors is visual. When handling raptors (except young nestlings) standard falconry hoods are used to keep them calm. The hood is placed on the bird immediately after capture and remains on until release. This reduces the stress to the bird and is safer for the biologists.

Hooded eagle fitted with CTT transmitter

2. Securing feet:

a. Vetwrap – An eagle can typically exert 25,000-psi pressure at the tip of its talons. For this reason, eagles’ feet are restrained once captured to protect both the bird and biologists. Vetwrap, a commercially available self-adhering elastic bandaging tape, is wrapped around each closed foot (4–6 wraps) to secure the talons.

b. Booties: The strength of a nestling eagle is not fully developed and simple booties made from small fleece drawstring bags are used to secure them.

3. Restraining devices:

a. Aba – Is a cloth jacket which is fitted over the wrists and back of a bird and is secured with a few wraps of elastic around the ankles, which has been used in Arabia for hundreds of years. This immobilizes the wings and feet but allows the breast to remain uncovered. It can also be arranged so that one wing can be extended for blood taking while the other wing and feet remain secured. The aba allows one person to safely handle a raptor (see Maechtle 1998).

b. Triangular bandage – A standard triangular bandage is used to restrain eagles for weighing by placing it over the back of the bird, bringing the long ends around the wings and tying over the bird’s breast. The loose ends of the knot are then tied around the bird’s ankles.

c. Toddler T-shirt – A toddler-sized T-shirt is sometimes used if it is necessary to immobilize an eagle for longer periods (>30 minutes). It is slipped over the bird’s hooded head and stretches to enclose the wings and body.

2.2.2.2 Banding

If not already banded, USFWS bands were placed on the bird’s leg above the foot. These are aluminum bird bands issued by the USGS Bird Banding Lab (see USGS Federal Bird Banding Manual). Bands have a numeric code and are sized to fit golden eagles.

2.2.2.3 Measurements

Birds were weighed with a metric spring scale while hooded and in a restraint device. Standard morphological characteristics including wing chord, tail length, beak, and talons were measured using a metric tape measure and calipers. Measurements, molt characteristics, and plumage were recorded and used to age and sex individuals whenever possible. A photographic record was kept for each bird transmittered and banded.

Taking measurements from Pahroc nestling in Nevada

2.2.2.4 Blood Samples for Pesticide and DNA Analysis

See Redig in Cade et al. (1996), Guide to Management of Peregrine Falcons at the Eyrie, for standard blood sample collection methods. Details regarding blood draw procedures can be found in the project Work Plan (AMEC 2013).

2.2.2.5 Transmitter Attachment

GPS satellite transmitters weighing less than 2 percent (%)–3% of the eagle’s total body weight (Bird Banding Lab Standard) were attached for this study; the two types of transmitters weigh 55 grams (g) and 65 g. To accommodate these larger transmitters with their multi-year lifespan, a backpack mount was used. All attachments are designed to allow the transmitter to fall off in due course. All transmitter-equipped eagles will be monitored for the duration of attachment.

Transmitters were attached as follows: two lengths of Teflon ribbon are threaded through channels in the top and bottom of the transmitter and knotted to prevent slippage. This creates four straps. The transmitter is centered on the bird’s back, 1 cm below the lowest cervical vertebrae. The two top straps are brought over the shoulders on either side of the neck until they cross over the breast. The lower straps are passed along the body under the wing and above the leg. All four straps are gathered at a point where they cross just below the top of the keel so they lie flat against the breast and are clamped in place with a pair of hemostats. The straps are adjusted until the proper fit is achieved (the transmitter is centered over the spine, the anterior end is just below the neck, and there is approximately 3.5 cm–5.0 cm of space is approximately 3.5 cm–5.0 cm of space between the back of the bird and the bottom of the transmitter

Eagle fitted with PTT transmitter when it is pulled strongly away from the bird’s back). The straps are then secured with stitches of waxed cotton embroidery thread tied with square knots. Each stitch passes through all four straps where they overlap. The strap ends are then trimmed and the edges sealed with “Fray Check” to prevent unraveling. The backpacks are attached with enough slack to allow freedom of movement and growth while not allowing the transmitter to be flipped over. The stitches will deteriorate over time and allow the transmitter to fall off. The number of stitches determines how long the bird will wear the transmitter, approximately one year per stitch, in moist climates, two or more years per stitch in drier climates. Four stitches were used in this study.

Completed stitching of transmitter backpack straps and sealing with “Fray Check”

2.2.3 Transmitter Systems

Two types of transmitters were used for this study. For locations where AT&T cell coverage is available and eagle flights may at least sporadically fall within range of cellular telephone towers, Cellular Transmitter Terminals (CTTs) were used as approved by range operations, while in more remote locations with no adequate cellular telephone coverage, Platform Transmitter Terminals (PTTs) were used. These are described in more detail below. Detailed manufacturer specifications were provided in the Work Plan (AMEC 2013).

CTTs communicate with researchers via Global System for Mobile cellular towers. We acquired and deployed five CTTs (three in Idaho and two in Utah) made by North Star Science and Technology (NSST). They are equipped with a GPS engine that takes precise locations on a programmed schedule. Each time they acquire a location they then attempt to contact a cellular tower and transmit that location to NSST’s web portal. If unsuccessful, that location is archived for transmittal the next time a connection is made. A successful connection transmits the current location plus as many as 49 archived locations, beginning with the oldest. When locations are received by the web portal they are immediately available. Each location is time-stamped and also provides the number of satellites used to determine that location, the battery’s voltage, and the altitude, speed, and heading of the CTT. Communication between the web portal and CTT is two-way during connection with cellular towers, so each CTT’s duty cycle can be reprogrammed by requesting changes on the web portal. Locations may be viewed in Google Earth on the portal and downloaded in comma separated value format. The CTTs deployed are powered by solar panel, weigh ~55 g and transmit to cell towers with 1–2 watts of power at 850, 900, 1800, and 1900 MHz. They have battery-powered very high frequency (VHF) transmitters weighing 3.6 g attached to aid in recovery of downed subjects for the following ~441 days after deployment.

CTT data collection and transmission

Platform Transmitter Terminals communicate with the Argos satellite system. Argos is a cooperative among the Centre National d’Etudes Spatiales (France), the National Aeronautics and Space Administration (U.S.), and the National Oceanic and Atmospheric Administration (U.S.). Administered in the U.S. by CLS America, Argos allows researchers to remotely track natural resources anywhere in the world. All PTTs transmit at ~401.65 MHz with a unique ID and under a duty cycle set by the researcher and implemented during manufacture. During “on” periods the PTT broadcasts its transmissions to any Argos satellite in view. CLS America estimates PTT locations using the principles of Doppler Shift in signal frequency as received by its satellite. They calculate the distribution within which the estimate lies; the standard deviation of this distribution estimates the accuracy of the location, and it is placed in a location class. Class 3 locations are considered the most accurate, and are estimated at better than 150 meters (m) on both axes, with a 250 m radius. Doppler PTTs as described generate only location estimates. GPS PTTs generate those same location estimates, but also have an incorporated GPS engine and transmit to Argos satellites the actual GPS locations taken in accordance with their programming. We fielded six total GPS PTTs in Utah and five in Nevada. They are solar powered, weigh ~65 g, transmit to Argos satellites eight of each 45 hours at ~225 megawatts (mW), are programmed to acquire 12 GPS locations daily, and have battery powered VHF transmitters weighing 3.6 g attached to aid in recovery of downed subjects for the following ~441 days after deployment. We downloaded data from CLS America each week and processed files to derive and assess location and sensor values. In addition to location estimates and GPS locations, data from PTTs include battery voltage and activity values that should increment as a viable subject moves, as well as temperature and altitude.

PTT data collection and transmission

Battery-powered VHF transmitters incorporated in CTT and PTT packages are easily tracked by receiver and directional antenna from the ground and by air. To arrive at frequencies to deploy in the field, we queried state, federal, AFB, and non-governmental organization researchers in Idaho, Utah, Nevada, and New Mexico. The frequencies between 149.940 and 150.999 MHz were approved by state and federal officials in Idaho, Utah, and New Mexico. We obtained lists of exact frequencies in use and arrived at those that would not conflict. CTT and PTT units were ordered with the appropriate VHF frequencies. NTTR limited the VHF frequency to 237 MHz to avoid potential conflict with range operations. Thus, PTTs and VHF units were ordered to accommodate that requirement for use in Nevada.

2.2.4 Telemetry Data Analysis

GPS locations and associated attributes such as time, date, heading, and altitude for each bird’s PTT or CTT were downloaded from the Argos system and North Star Portal. Argos data was converted to a usable format for GIS and all data points were reviewed to remove erroneous outliers. Telemetry locations for each bird were plotted in ArcGIS and home ranges were analyzed using the Kernel Density Estimate tool (Silverman 1986, Wand & Jones 1995). Since locations were recorded at set diurnal intervals of up to 12 per day, every single movement for each bird is not tracked. In addition, GPS locations could not be recorded on some days or for periods of time due to perching out of view of GPS satellites or low battery voltage that may have been the result of perch locations, weather conditions, or feather coverage. Thus, the Kernel Density statistical application was used to derive home range probability maps from the recorded telemetry locations. Utilization contours which represent the odds of re-locating the bird within that area were created based on the analysis. The 95% Home Range corresponds to the area in which the probability to find (relocate) the animal is equal to 0.95. The 50% Core Range is the area with a 0.50 relocation probability. The Core Range is always smaller than the 95% Home Range. All available altitude data was plotted for each bird over time to generate a scatter chart in Microsoft Excel. Altitude measurements indicate the height (in feet) of the bird above the surface of the earth at their recorded GPS location. The GPS engine in the transmitters utilizes a mathematical model which roughly approximates the geodetic model of the earth at that location and references the bird’s altitude to this model.

2.3 Nesting Surveys

Aerial and ground surveys were conducted following established eagle survey protocols (Pagel et al. 2010, Driscoll 2010, USFWS 2011).

2.3.1 Aerial Surveys

Helicopter surveys are the preferred technique for locating golden eagle nests and determining their annual occupancy when large areas of difficult terrain must be covered. Surveys were conducted following procedures for aerial surveys outlined in the Interim Golden Eagle Inventory and Monitoring Protocols issued by USFWS (Pagel et al. 2010) and recent Draft Eagle Conservation Plan Guidelines (USFWS 2011).

Golden eagle nest surveys consisted of visually inspecting all suitable cliff faces, other vertical or nearly vertical substrates, and some types of trees, for the presence of stick nests and nesting eagles. All medium- to large-sized nest locations were recorded using a hand-held GPS. The nests were photographed and data were collected in a field notebook and transferred to data sheets. The accuracy of the sex/age class determinations of each observed eagle was based on the field experience of the observers. Only experienced and highly qualified observers conducted the surveys. The route typically included all canyons, drainages, and forested slopes within the study area. Two biologists (a primary and secondary surveyor) sitting on opposite sides of the helicopter conducted each survey.

Each canyon or cliff face was flown up-gradient and then down to view all cliffs and trees from the primary surveyor’s side of the aircraft. Contouring passes were made at different elevations to fully cover tall cliffs and long, steep slopes. In areas of mild slopes and flatlands with numerous trees suitable for nesting, a grid pattern was often flown with 500 meters separating flight lines. Two or more passes were performed at slower speeds at cliffs that had large nests, copious whitewash, or that were otherwise suspected of having nests, to allow closer observation, marking, photography, and documentation of nest conditions, presence of nestlings and adult birds. Average speed during cliff observation flights was approximately 10 to 20 miles per hour. Distance from the helicopter to the various potential nesting structures ranged from 20 m–200 m. In addition to cliffs, canyons, and trees in the flight survey area, any transmission lines traversing the survey areas were surveyed.

Prior to the start of the 2013 breeding season, a winter reconnaissance helicopter survey was conducted to search for suitable habitat and potential nests for previously un-surveyed areas on MAFR, SCR, and JBR. The UTTR reconnaissance had to be cancelled due to weather conditions (heavy fog) which grounded the helicopter. Helicopter nest surveys were completed between March 16 and May 29, 2013; and March 22 and May 17, 2014. Specific dates of these surveys are provided in Table 2-1. After initial nesting surveys were completed, these were followed up with either aerial or ground surveys to determine fledgling success rates.

Table 2-1.

Summary of Aerial Survey Days

May 17, 2014 (productivity)

May 24–27, 2013 (completed survey of Restricted Airspace) April 7-9, 2014 (completed aerial survey of ranges and RA)

Aerial nest surveys were completed for the 2013 and 2014 nesting season by qualified raptor biologists Brian Latta and Mike Yates of BRC. These surveys were conducted within suitable nest habitat at UTTR, SCR, JBR, MAFR, and associated Restricted Airspace where existing nest information or on-going programs was lacking. Portions of the suitable habitat on UTTR were excluded from the aerial survey area as active nests had been documented as recently as 2012 and were monitored from the ground by Select Engineering Services in 2013 and by UTTR biologists in 2014. In addition, ongoing eagle nest surveys and migratory studies are being conducted by other contractors at Dugway and by Hawkwatch within the UTTR Restricted Airspace beyond the military ranges. The areas that are adequately covered to meet study objectives under this contract were excluded to avoid duplicating efforts, and the remaining study area was surveyed by the AMEC team for the 2013 and 2014 field seasons. Excluded areas include mountain ranges within the southeastern portion of the Restricted Airspace and are shown on the nest survey maps in Section 3. Dugway and Hawkwatch nest survey data was not made available for inclusion in this report. Access approvals to fly over UTTR and the associated restricted airspace limited the survey timeframes in 2013, thus portions of the study area could only be covered during the late spring survey for that year (May 24–27, 2013). A full survey of the UTTR and restricted airspace aerial study area was completed in April 2014.

NTTR has an ongoing aerial survey program for the entire range under separate contract that was continued through 2013 and 2014. The results of these surveys are included herein. A portion of the MOA was surveyed in 2013 via helicopter in order to identify active nest sites and potential birds for trapping. The extent of the survey area was limited to the eastern portions of the MOA based on NTTR operation approvals.

The entirety of the MAFR, JBR, and SCR, as well as the associated Restricted Airspace, was surveyed via helicopter in 2013 as a full nest survey had not been previously conducted for these ranges according to USFWS protocols. Based on a lack of nest suitable habitat and absence of golden eagle nesting territories, it was determined that aerial nest surveys were not warranted for MAFR in 2014. A full aerial nest survey of SCR and JBR was conducted in 2014.

2.3.2 Ground-Based Surveys

In some instances, follow-up ground surveys for golden eagle occupancy/productivity were more appropriate than conducting addition aerial surveys. Ground surveys were conducted either on foot, using all-terrain vehicles, or using other suitable off-road vehicles or some combination of these methods. For safety reasons, field surveyors surveyed remote areas as two-person teams. They were sent to pre-determined locations to search any landscape features where golden eagle nesting was expected or known to occur based on previous survey efforts. The observers were all experienced with identifying golden eagles and their nesting behaviors. They were assisted by the use of binoculars (10x–12x) and spotting scopes (70 millimeter, 20x–60x). Free-flying eagles were aged according to Bloom and Clark (2002). Nestling eaglets were aged according to Hoechlin (1976). Following aerial nest surveys, 11 days of follow-up ground surveys were completed in 2013 within the SCR and JBR focusing on previously documented nest sites. These surveys were completed on May 24, 26-30, and June 1-4, 6, 2013. Ground-based nest productivity surveys were completed in June 2014 for UTTR. No ground- based surveys occurred at SCR/JBR in 2014 as productivity surveys were conducted in mid-May via helicopter.

2.3.3 Occupancy and Productivity

Occupancy was defined by the number of golden eagle pairs holding territories throughout the breeding season, whether or not they attempted to breed in a given year. Occupancy was determined by observation of eagle pairs performing courtship activities (e.g., undulating flight displays, nest building, and copulation) prior to egg-laying (late December to mid-March). By having two biologists observe together or from separate observation points while maintaining communications with handheld radios, it was possible to follow both members of a pair of eagles and or any additional eagles in the area (sub-adults, intruding adults, and neighboring pair members). While occupancy is best determined by ground observations, we attempted to determine occupancy during aerial surveys in parts of the study area where ground access was limited by determining whether new material had been added to existing nests or by observation of resident pairs if egg-laying had not occurred within a given territory.

Productivity is the number of young produced per occupied territory. Productivity data was collected either by helicopter or by ground survey teams. The preferred method for second visits to nesting locations was determined based on logistical considerations and cost effectiveness of each optional method.

2.4 Prey Analysis

Observations of the available golden eagle prey base (e.g., lagomorphs and rodents) were recorded incidentally during ground surveys. In addition, at the end of the 2013 nesting season, a team of two biologists examined the prey contents at a representative sample of active nest sites on UTTR and SCR. This was conducted by climbing into the nest after young fledged and collecting all prey remains. Nest climbs occurred in August 2013 at five nest sites on UTTR (Figure 2-1) and one nest site on SCR/JBR (Figure 2-2). Prey remains were sorted and identified by Dr. Paul Collins, Santa Barbara Museum of Natural History. No nest climbs occurred in 2014 for purposes of prey analysis.

Prey remains collected at nest site

2.5 Bait Stations

A variety of raptors, including golden eagles, are likely to spend all or some of their non-breeding seasons (fall and winter) on the ranges being studied. Systematic ground surveys/point-counts to document and quantify golden eagle and other diurnal raptor use of each range were not feasible due to access restrictions on ranges such as NTTR and UTTR South. Standardized raptor surveys were conducted in the vicinity or in overlapping study areas for all ranges with the exception of MAFR

To augment population data being collected by other parties, bait stations were included in this study. Bait stations were set in an open area and a carcass (e.g., road-killed deer, antelope, elk, or livestock) was laid out for eagles to feed upon. Stations were generally located in areas such as open grassy slopes where eagles were likely to be comfortable landing on the ground. Remote cameras with motion sensors were installed to record images of animals coming to feed on carcasses. Periodically, a biological technician put out a new carcass and exchanged the camera chip on which the images are stored for a new one. This was typically done every 3 to 4 weeks based on persistence of the carcasses and to avoid habituating animals to sites. A detailed bait station setup and monitoring protocol developed for NTTR is attached as Appendix C. Permits from state wildlife agencies were obtained for roadkill carcass collection (Appendix B). Where feasible, contact was made with local ranchers to procure dead livestock.

In total, 14 bait stations with remote cameras were set up in strategic locations at UTTR, SCR/ JBR, and NTTR by our biologists. Data was collected for the 2013 and 2014 field seasons. Specific bait station locations are shown on Figure 2-3 (UTTR), Figure 2-4 (SCR/JBR), and Figure 2-5 (NTTR).

All photos from each camera station were reviewed by a biologist after collection of the camera chip. Species captured by the camera were identified and the number of presumed individuals recorded based on time gaps as recorded for each photo. Several consecutive photos within a short period of time were assumed to represent the same individuals continuously setting off the camera. Time gaps were estimated based on perceived time of day in the photographs. All photos from NTTR were previewed by operations staff before they were released to AMEC.

2.6 Point Counts

Since base restrictions did not allow for the establishment of bait stations at MAFR, a roadside survey route was developed covering the range and Restricted Airspace as an alternative. A total of 25-point count locations along this route were established in consultation with Cannon AFB natural resources staff (Figure 2-6). Point count locations are surveyed monthly by biologist George Britt, allowing us to gather seasonal data regarding golden eagle use of the site in a systematic way. The surrounding areas of each point count location were scanned for 10 to 30 minutes with the aid of binoculars and/or spotting scopes. Data on any raptors observed was recorded on standardized field datasheets.

Road transect surveys for raptors on MAFR began in August 2013 to capture the start of the non-breeding season and were initially conducted every two weeks. As a result of limited data from the two-week time protocol, surveys were changed to once a month. Each transect was driven by car for maximum coverage and efficiency. Transect areas were organized into four different routes/areas that were labeled A, B, C and D. These routes averaged 20 miles in length. Each transect area and had 6-7 point count stations labeled A1, A2, and so forth for stationary observations. Surveys were conducted during daylight hours between 0800 and 1800, and on days of forecasted clement weather. Transects were rotated so that the first survey session started with Transect A, followed by B, C and D in order. The fifth survey session started at Transect A through D again, but from the opposite end. Transects were driven at approximately 15-20 miles per hour, while continuously searching for raptors. Point count stops were limited to 5 minutes, with the observer in a location that gives 360 degree views. When a raptor was sighted, the vehicle was stopped and observers recorded data. Data records included the following: location of observer by GPS or station number; species; distance and direction to bird from observer; number of individuals; flight direction and height; bird behavior and notes of interest. Survey tracks were recorded by handheld GPS units. Road transect surveys were concluded in April 2014. At this point, birds were breeding in suitable areas off site and no longer likely to migrate through the area. Thus, further surveys were not likely to yield data on golden eagles.

3.0 RESULTS

With the exception of the transmitter summary below, study results are discussed in this section by individual range.

3.1 Summary of…