USE OF SIMULATED HIGHWAY
UNDERPASS CROSSING
STRUCTURES BY FLAT- TAILED
HORNED LIZARDS
( PHRYNOSOMA MCALLII)
Final Report 594
Prepared by:
Mikele L. Painter and Michael F. Ingraldi
Arizona Game and Fish Department
Research Branch
2221 West Greenway Road
Phoenix, Arizona 85023
May 2007
Prepared for:
Arizona Department of Transportation
206 South 17th Avenue
Phoenix, Arizona 85007
In cooperation with
U. S. Department of Transportation
Federal Highway Administration
DISCLAIMER
The contents of this report reflect the views of the authors who are responsible for the facts and
the accuracy of the data presented herein. The contents do not necessarily reflect the official
views or policies of the Arizona Department of Transportation or the Federal Highway
Administration. This report does not constitute a standard, specification, or regulation. Trade or
manufacturers' names which may appear herein are cited only because they are considered
essential to the objectives of the report. The U. S. Government and the State of Arizona do not
endorse products or manufacturers.
Technical Report Documentation Page
1. Report No.
FHWA- AZ- 07- 594
2. Government Accession No.
3. Recipient's Catalog No.
5. Report Date
May 2007
4. Title and Subtitle
USE OF SIMULATED HIGHWAY UNDERPASS CROSSING
STRUCTURES BY FLAT- TAILED HORNED LIZARDS
( PHRYNOSOMA MCALLII)
6. Performing Organization Code
7. Author
Mikele L. Painter and Michael F. Ingraldi
8. Performing Organization Report No.
10. Work Unit No.
9. Performing Organization Name and Address
Arizona Game and Fish Department
Research Branch
2221 W. Greenway Road
Phoenix, Arizona 85023
11. Contract or Grant No.
JPA 05- 017T / KR05- 0494TRN
13. Type of Report & Period Covered
FINAL REPORT,
June 2005 – February 2007
12. Sponsoring Agency Name and Address
Arizona Department of Transportation
206 S. 17th Avenue
Phoenix, Arizona 85007
ADOT Project Manager: Estomih ( Tom) Kombe
14. Sponsoring Agency Code
15. Supplementary Notes
Prepared in cooperation with the U. S. Department of Transportation, Federal Highway Administration
16. Abstract
The flat- tailed horned lizard ( Phrynosoma mcallii) occupies a restricted range in the Lower Sonoran Desert of
southwest Arizona, southeast California, and adjacent land in Mexico. Because they exhibit behavior patterns
that include basking and remaining motionless when danger approaches, flat- tailed horned lizards are
particularly susceptible to mortality on roads. Therefore, roads and new road construction are recognized as
threats influencing the long- term persistence of this species. The propensity for flat- tailed horned lizards to
use culverts as road crossing structures to avoid vehicle- caused mortality is unknown. From 2005- 2006 we
studied flat- tailed horned lizard use of a variety of simulated road crossing structures. The study objectives
were to 1) determine if flat- tailed horned lizards will pass through culverts of sizes commonly used in road
construction, and 2) compare and describe the characteristics of culverts used by flat- tailed horned lizards to
those not used. We built a testing facility with six culverts of three dimensions and two interior lighting
options. All culverts were 40 feet long; the three types included 24- inch diameter steel culverts, 36- inch
diameter steel culverts, and 4- foot tall by 8- foot wide box culverts. One of each type of culvert was lit with
skylights, and one of each type of culvert had only natural light from the ends. Light and temperature
conditions in the culverts were evaluated during the study. Out of 54 flat- tailed horned lizards placed in the
testing facility, we observed 12 complete crossings. The 36- inch diameter culvert without skylights was used
five times. The 24- inch diameter culvert with skylights was not used, and other culvert designs were each
used once or twice. Results indicated that flat- tailed horned lizards can use culverts as road crossing
structures, but the evidence did not reveal a strong selection for or against any culvert type.
Recommendations for employing appropriate road crossing structures are discussed.
17. Key Words
Arizona, culvert, highway crossing structure,
herpetofauna, horned lizard, wildlife mitigation,
roadway crossing
18. Distribution Statement
Document is available to the U. S.
Public through the National
Technical Information Service,
Springfield, Virginia, 22161
19. Security Classification
Unclassified
20. Security Classification
Unclassified
21. No. of Pages
38
22. Price
23. Registrant's Seal
SI* ( MODERN METRIC) CONVERSION FACTORS
APPROXIMATE CONVERSIONS TO SI UNITS APPROXIMATE CONVERSIONS FROM SI UNITS
Symbol When You Know Multiply By To Find Symbol Symbol When You Know Multiply By To Find Symbol
LENGTH LENGTH
in inches 25.4 millimeters mm mm millimeters 0.039 inches in
ft feet 0.305 meters m m meters 3.28 feet ft
yd yards 0.914 meters m m meters 1.09 yards yd
mi miles 1.61 kilometers km km kilometers 0.621 miles mi
AREA AREA
in2 square inches 645.2 square millimeters mm2 mm2 Square millimeters 0.0016 square inches in2
ft2 square feet 0.093 square meters m2 m2 Square meters 10.764 square feet ft2
yd2 square yards 0.836 square meters m2 m2 Square meters 1.195 square yards yd2
ac acres 0.405 hectares ha ha hectares 2.47 acres ac
mi2 square miles 2.59 square kilometers km2 km2 Square kilometers 0.386 square miles mi2
VOLUME VOLUME
fl oz fluid ounces 29.57 milliliters mL mL milliliters 0.034 fluid ounces fl oz
gal gallons 3.785 liters L L liters 0.264 gallons gal
ft3 cubic feet 0.028 cubic meters m3 m3 Cubic meters 35.315 cubic feet ft3
yd3 cubic yards 0.765 cubic meters m3 m3 Cubic meters 1.308 cubic yards yd3
NOTE: Volumes greater than 1000L shall be shown in m3.
MASS MASS
oz ounces 28.35 grams g g grams 0.035 ounces oz
lb pounds 0.454 kilograms kg kg kilograms 2.205 pounds lb
T short tons ( 2000lb) 0.907 megagrams
( or “ metric ton”)
mg
( or “ t”)
mg megagrams
( or “ metric ton”)
1.102 short tons ( 2000lb) T
TEMPERATURE ( exact) TEMPERATURE ( exact)
º F Fahrenheit
temperature
5( F- 32)/ 9
or ( F- 32)/ 1.8
Celsius temperature º C º C Celsius temperature 1.8C + 32 Fahrenheit
temperature
º F
ILLUMINATION ILLUMINATION
fc foot candles 10.76 lux lx lx lux 0.0929 foot- candles fc
fl foot- Lamberts 3.426 candela/ m2 cd/ m2 cd/ m2 candela/ m2 0.2919 foot- Lamberts fl
FORCE AND PRESSURE OR STRESS FORCE AND PRESSURE OR STRESS
lbf poundforce 4.45 newtons N N newtons 0.225 poundforce lbf
lbf/ in2 poundforce per
square inch
6.89 kilopascals kPa kPa kilopascals 0.145 poundforce per
square inch
lbf/ in2
SI is the symbol for the International System of Units. Appropriate rounding should be made to comply with Section 4 of ASTM E380
TABLE OF CONTENTS
I. EXECUTIVE SUMMARY............................................................................................ 1
II. INTRODUCTION......................................................................................................... 3
III. METHODS .................................................................................................................. 5
A. STUDY SITE............................................................................................................ 5
B. FACILITY CONSTRUCTION................................................................................. 6
C. MONITORING FLAT- TAILED HORNED LIZARD USE OF
EXPERIMENTAL CULVERTS............................................................................. 9
D. MEASURING TEMPERATURE AND LIGHT INTENSITY .............................. 11
E. ANALYSIS ............................................................................................................. 12
IV. RESULTS ................................................................................................................ 15
A. FLAT- TAILED HORNED LIZARD USE OF EXPERIMENTAL
CULVERTS .......................................................................................................... 15
B. TEMPERATURE AND LIGHT INTENSITY....................................................... 18
V. CONCLUSIONS......................................................................................................... 21
VI. RECOMMENDATIONS........................................................................................... 23
VII. BIBLIOGRAPHY .................................................................................................... 25
APPENDIX A. RECORDS AND INTERPRETATIONS OF FLAT- TAILED
HORNED LIZARD REMOTE TELEMETRY DATA........................ 27
APPENDIX B. SURVIVAL DATA AND FATE OF FLAT- TAILED HORNED
LIZARDS............................................................................................... 31
LIST OF FIGURES
Figure 1. Figure 1. Flat- tailed horned lizard study site from 2005- 2006........................... 5
Figure 2. Layout of the testing facility ( not to scale).......................................................... 7
Figure 3. Soil from the site distributed through the 36- in diameter culvert without
skylights............................................................................................................... 8
Figure 4. Entrance of the 4- ft by 8- ft box culvert with a skylight ( upper right) and
headwalls ( dark brown) ....................................................................................... 8
Figure 5. Skylights positioned on a 24- in diameter culvert ................................................ 8
Figure 6. Flat- tailed horned lizard with a radio telemetry transmitter attached.................. 9
Figure 7. Flat- tailed horned lizard exhibiting typical hiding behavior while
carrying a radio telemetry transmitter. .............................................................. 10
LIST OF TABLES
Table 1. Description of real road culverts selected for temperature comparison to
simulated road crossing structures .................................................................... 12
Table 2. Information on each flat- tailed horned lizard used in the simulated road
crossing structure experiment ( 2005- 2006)....................................................... 16
Table 3. Summary of flat- tailed horned lizard use of simulated road crossing
structures ( 2005- 2006). ................................................................................... 17
Table 4. Light intensity and temperature discrepancies at the testing
facility ( Jun- Sep) ............................................................................................... 18
Table 5. Games- Howell test results ( P- values) of multiple comparisons among
temperature discrepancies recorded at simulated culverts ................................ 18
ACKNOWLEDGEMENTS
The Arizona Department of Transportation ( ADOT) and the Federal Highway
Administration ( FHWA) provided funding for this project. The research team thanks the
following Arizona Game and Fish Department ( AGFD) Research Branch personnel for
their time and effort during this project: Dennis Abbate, Mylea Bayless, Scott Blackman,
Caley Boone, R. J. Genoa, David Grandmaison, Zach Hurst, Sarah Karasz, Shawn
Lowery, Ron Mixan, Eddie Moreno, Sarah Newell, Steve Partridge, Beatriz Vizcarra, and
Renee Wilcox. Ron Pearce provided administrative support from the Marine Corps Air
Station Range Management Department. Bryan Morrill ( MCASRMD) and Lin Piest
( AGFD, Yuma) helped enormously with each stage of the project, including
development, construction, and implementation. The research team also thanks Steve
Thomas ( FHWA) for finding the funds for this important project, and Dr. Tom Kombe
( ADOT) for his administrative contributions. Ray Schweinsburg ( AGFD) administered
our grant and provided valuable editorial input.
The Arizona Game and Fish Department prohibits discrimination on the basis of race,
color, sex, national origin, age and disability in its programs and activities. If anyone
believes they have been discriminated against in any of AGFD’s programs or activities,
including its employment practices, the individual may file a complaint alleging
discrimination directly with AGFD Deputy Director, 2221 W. Greenway Rd., Phoenix,
AZ 85023, ( 602) 789- 3290 or US Fish and Wildlife Service, 4040 N. Fairfax Dr., Ste.
130, Arlington, VA 22203.
Persons with a disability may request a reasonable accommodation, such as a sign
language interpreter, or this document in an alternative format, by contacting the AGFD
Deputy Director, 2221 W. Greenway Rd., Phoenix, AZ 85023, ( 602) 789- 3290 or by
calling TTY at 1- 800- 367- 8939. Requests should be made as early as possible to allow
sufficient time to arrange for accommodation.
1
I. EXECUTIVE SUMMARY
The flat- tailed horned lizard ( Phrynosoma mcallii) occupies a restricted range in the
Lower Sonoran Desert of southwest Arizona, southeast California, and adjacent land in
Mexico. Because they exhibit behavior patterns that include basking and remaining
motionless when danger approaches, flat- tailed horned lizards are particularly susceptible
to mortality on roads. More importantly, highways fragment areas of habitat and isolate
segments of lizard populations. Depending on the size of the isolated habitat patches,
these populations may be non- viable without connections to the larger population.
Therefore, roads and new road construction are recognized as threats influencing the
long- term persistence of this species.
The propensity for flat- tailed horned lizards to use culverts as road crossing structures to
avoid vehicle- caused mortality is unknown. From 2005- 2006, Arizona Game and Fish
Department researchers studied flat- tailed horned lizard use of a variety of simulated road
crossing structures. The study objectives were to 1) determine if flat- tailed horned lizards
will pass through culverts of sizes commonly used in road construction, and 2) compare
and describe the characteristics of culverts used by flat- tailed horned lizards to those not
used. The research team built a testing facility south of Yuma, Arizona, with six culverts
of three dimensions and two interior lighting options. All culverts were 40 feet long; the
three types included 24- inch diameter steel culverts, 36- inch diameter steel culverts, and
4- foot tall by 8- foot wide box culverts. One of each type of culvert was lit with skylights,
and one of each type of culvert had only natural light from the ends. Light and
temperature conditions in the culverts were evaluated during the study. Out of 54 flat-tailed
horned lizards placed in the testing facility, 12 complete crossings were observed.
The 36- inch diameter culvert without skylights was used five times. The 24- inch
diameter culvert with skylights was not used, and other culvert designs were each used
once or twice. Results indicated that flat- tailed horned lizards can use culverts as road
crossing structures, but the evidence did not reveal a strong selection for or against any
culvert type.
Because the 24- inch diameter culverts were used less frequently than the larger culverts
and they seemed more susceptible to movement of soil, the research team tentatively
recommends against using these culverts as standard road crossing structures for flat-tailed
horned lizards. While the 36- inch diameter and the 4- foot by 8- foot box culverts
were not immune to movement of sandy soil, they were not as vulnerable as the smaller
culverts. Although the 36- inch diameter culvert may be the best option, either of the
larger styles could work as a crossing structure, as long as fencing is used to funnel
animals toward the culvert, it remains passable, preferably holds some soil on the floor,
and allows some daylight through its length.
2
Other issues to consider in designing appropriate road crossing structures include:
regular maintenance ( i. e., maintaining substrate in culverts and ready access to culvert
entrances), how many to install, where to install them, position under the road, and
topography of the crossing site. Although this study showed that in an experimental
situation flat- tailed horned lizards are capable of moving through culverts, they may
exhibit different reactions to culverts under normal circumstances in their own territories
or during typical dispersal. To further test road crossing structures as a viable mitigation
measure for flat- tailed horned lizards, use of actual culverts under roads ( with exclusion
fencing) should be documented for this species in situ.
3
II. INTRODUCTION
The flat- tailed horned lizard ( Phrynosoma mcallii) is a small cryptic lizard restricted to
the western Sonoran Desert in southeast California, southwest Arizona, and adjacent land
in Mexico. It is commonly found below 820 feet in areas with flat to modest (< 3%)
slopes. The flat- tailed horned lizard was proposed for threatened species listing by the
U. S. Fish and Wildlife Service ( Service) in 1993. The proposal was subsequently
withdrawn in 1997 when it was determined that population trend estimates were
ambiguous, and threats ( i. e., habitat loss/ degradation) to the species did not warrant
listing. In 1997, flat- tailed horned lizards gained protective status on public lands under a
conservation agreement signed by several state and federal agencies. This conservation
agreement implements the Flat- tailed Horned Lizard Rangewide Management Strategy
( Flat- tailed Horned Lizard Interagency Coordinating Committee 2003). On 7 December
2005 the Service announced reinstatement of the 1993 proposed rule, but again withdrew
it on 28 June 2006 ( 71 FR 36745).
In response to increasing transportation demands in southwestern Arizona, the Arizona
Department of Transportation ( ADOT) is developing plans to build new highways and
improve existing highways within flat- tailed horned lizard habitat. The Rangewide
Management Strategy recognizes roads and new road construction as threats influencing
the long- term persistence of this species. Since flat- tailed horned lizards exhibit
behaviors that include basking and remaining motionless when danger approaches, they
are particularly susceptible to mortality on roads ( Flat- tailed Horned Lizard Interagency
Coordinating Committee 2003). More importantly, highways fragment areas of habitat
and isolate segments of wildlife populations. Depending on the size of the isolated
habitat patches, these populations may be non- viable without connections to the larger
population ( Trombulak and Frissell 2000). The Rangewide Management Strategy
stipulates the installation of effective culverts to mitigate road effects and maintain
connectivity between flat- tailed horned lizard populations bisected by paved roads
proposed or authorized by signatories to the conservation agreement. It also states that
the Flat- tailed Horned Lizard Interagency Coordinating Committee shall provide a
culvert design. To date, there has been little information to guide this effort.
Highway crossing structures can mitigate some roadway effects on wildlife, but only if
the target species use them ( Ng et al. 2004). Road permeability can be improved for
lizards and other wildlife by installing culverts as crossing structures ( Yanes et al. 1995,
Ascensão and Mira 2007). Culverts accompanied by proper exclusion fencing further
improve connectivity between road- fragmented habitat patches and decrease roadway
mortality ( Dodd et al. 2004, Aresco 2005). Some animals exhibit aversion to certain
types of crossing structures and may not use a culvert if it is not suitably designed
( Rodriguez et al. 1996, Ng et al. 2004). Use may be influenced by the culvert’s internal
temperature, lighting, or overall width ( Ruediger 2001).
4
The propensity for flat- tailed horned lizards to use culverts as road crossing structures is
unknown. To determine if culverts can mitigate road effects on flat- tailed horned lizards,
it is imperative to determine crossing structure parameters that are suitable for the
species. The purpose of this study was to test flat- tailed horned lizard use of several
different simulated road- crossing structures, and assist decisions regarding mitigation of
highway construction and maintenance within flat- tailed horned lizard habitats.
This project was designed to test flat- tailed horned lizard use of commonly employed
road crossing structures and provide information that can be applied to road design and
maintenance questions. The project addressed the following objectives:
• Determine if flat- tailed horned lizards will pass through culverts of sizes
commonly used in road construction.
• Compare and describe the characteristics of culverts used by flat- tailed horned
lizards to those not used.
5
III. METHODS
A. STUDY SITE
The study site was located approximately 10 miles south of Yuma, Arizona on the Barry
M. Goldwater Range ( Figure 1). The biotic community is classified as the Lower
Colorado River Valley subdivision of the Sonoran Desert. Dominant vegetation includes
creosote bush ( Larrea tridentata), white bursage ( Ambrosia dumosa), and big galleta
( Pleuraphis rigida). Topography is gently rolling with broad dunes of sandy loam, and
elevation ranges from 100- 400 feet above sea level ( Brown 1994). Mean summer ( June-
September) temperature and rainfall are 90 degrees Fahrenheit and 3/ 10 inches,
respectively ( TWC 2007).
Figure 1. Flat- tailed horned lizard study site from 2005- 2006
Yuma
Phoenix
Tucson
Flagstaff
Study Site
N
6
B. FACILITY CONSTRUCTION
In 2005 the research team built a facility to test potential use of highway culverts
currently used by ADOT to control water flow and erosion. The testing facility ( Figure
2) was designed as a hexagon ( 100 feet/ side, 6/ 10 acre) constructed with ¼ - inch mesh
hardware cloth 36 inches tall, buried 6 inches and held up by ¼ - inch rebar. Midway on
each side of the hexagon, we installed a 40- foot long culvert connected to a 10- foot by
10- foot hardware cloth peripheral enclosure. Ground inside the fenced area was not
disturbed to preserve natural characteristics of the vegetation and soil. The length of
culverts used in this study was similar to that of culverts used under typical two- lane
roads. Four- lane roads typically have an open median between the opposing traffic
directions. To maintain even substrate conditions throughout the testing facility, sand
was distributed inside each culvert to thoroughly cover the floor 1- 3 inches deep ( Figure
3). The R- value ( insulation coefficient) of a road ( asphalt and gravel fill) was estimated
to be approximately 22, so each culvert was covered with approximately 18- 24 inches of
soil and/ or rigid foam insulation ( R- Tech expanded polystyrene; Insulfoam, Tacoma,
Washington, USA) to simulate thermal properties of an actual culvert under a road.
The testing facility included three types of culverts and two interior lighting options.
Culvert types included 24- inch diameter galvanized steel culverts, 36- inch diameter
galvanized steel culverts, and 4- foot tall by 8- foot wide box culverts. The steel culverts
were the same as those in use by ADOT. The box culverts were constructed of ¾ - inch
plywood and framed with 2- inch by 4- inch wood posts ( Figure 4). Box culverts were
designed to mimic those made of concrete in use by ADOT. Each culvert received one of
two lighting options: light or dark. The “ light” culverts were lit inside with skylights; the
“ dark” culverts received only natural light from the ends. For the skylight option, at least
one 12- inch tubular skylight was installed midway into one of each type of culvert.
Because the 24- inch and 36- inch culverts were much darker than the box culverts, they
were fitted with two additional skylights. In 2005, sunlight was directed into the mouth
of these crossing structures with 22- inch flexible tubular skylights suspended from the
top half of the culvert openings. These terminal skylights reduced the entrance diameter
of these culverts by one- third to one- half. Interior lighting conditions were improved in
2006 by removing the terminal skylights, and installing two 10- inch tubular skylights, 10
feet away on either side of the midway skylight ( Figure 5).
7
Figure 2. Layout of the testing facility ( not to scale)
Notes: Total dimensions of the facility were approximately 300 feet by 300 feet. Each
enclosure was constructed of 36- inch hardware cloth buried approximately 6 inches and
held up by 1/ 4- inch rebar. The crossing structures ( S1 – S6) were constructed as follows:
S2 and S5 were 24- inch culvert piping; S3 and S6 were 36- inch culvert piping; and S1
and S4 were 4- foot tall by 8- foot wide simulated box culvert ( constructed of 3/ 4- inch
plywood). S2, S4, and S6 had skylights illuminating the crossing structures internally.
All culverts had approximately 18- 24 inches of soil or comparable insulation covering
each structure. Three radio telemetry receiver- data loggers each operated two antennas
of coaxial cable.
Approximately 300 ft
S1
S4
S5
S3
S2
S6
Center
enclosure
( 100 ft/ side)
Coaxial cable
~ 64 ft long
Radio
telemetry
receiver/ data
logger
Peripheral
enclosure
10x10 ft
Culvert
40 ft long
Ν
8
Figure 3. Soil from the site distributed
through the 36- in diameter culvert
without skylights.
Figure 4. Entrance of the 4- ft by 8- ft box
culvert with a skylight ( upper right) and
headwalls ( dark brown).
Figure 5. Skylights positioned on a 24- in diameter culvert.
Notes: In the background is the main enclosure. In the left foreground is the small
peripheral pen that prevents flat- tailed horned lizards from escaping if they walk though
the culvert. Plywood headwalls minimize sand loss at the ends.
9
C. MONITORING FLAT- TAILED HORNED LIZARD USE OF
EXPERIMENTAL CULVERTS
From September through October 2005 and June to September 2006, flat- tailed horned
lizards were captured from approved locations on the Barry M. Goldwater Range and
adjoining Bureau of Reclamation land. The research team recorded capture coordinates
( UTM, NAD 1927), sex, and length ( 2005, total length; 2006 snout- to- vent length) for
each individual. Only lizards ≥ 1 year old were used in the study. Either a 0.36- gram or
a 0.77- gram radio transmitter ( models LB- 2N or BD- 2, respectively; Holohil Systems
Ltd., Carp, Ontario, Canada) was affixed on the back of each individual with Dap brand
silicon aquarium sealant. After covering the tags with sealant, they were dusted with
sand for camouflage. Each individual also received a unique identification mark on the
belly and tail with black permanent marker. To ensure attachment and tag performance,
tags were activated and affixed the night before releasing the flat- tailed horned lizards
into the testing facility ( Figures 6 and 7).
Figure 6. Flat- tailed horned lizard with a radio telemetry transmitter attached.
Notes: The larger rod on the left side of the lizard’s back is a radio frequency
identification transponder that we tested unsuccessfully in 2005. The traditional radio
telemetry transmitter ( Holohil model LB- 2N) is on the right side of the lizards back, with
the thin wire projecting posteriorly. Most lizards only carried the telemetry transmitter.
10
Figure 7. Flat- tailed horned lizard exhibiting typical hiding behavior while carrying a
radio telemetry transmitter.
Anywhere from six to eight flat- tailed horned lizards were in the testing facility at any
one time. In 2005 the research team experimented with radio frequency identification
( RFID) transponders, but the system failed to work at the study site ( Painter and Ingraldi
2005). In 2006 only traditional radio telemetry equipment was used to monitor lizard
movements.
All flat- tailed horned lizards were released in the morning, in the center of the main
enclosure where all six culverts were equally available for selection. Because the testing
facility contained several active ant nests, supplemental food was not provided. The
research team monitored movement ( i. e., use of each crossing structure) of each
individual lizard for 10 days. After 10 days, or death of an individual in the testing
facility, animals were replaced with new individuals. General location and status of each
animal was determined with handheld receivers at least every third day. If an animal was
lost, circumstances of the loss were noted. After 10 days in the testing facility, surviving
individuals were taken out, their tags removed, and released at their point of capture.
Animals originally found on a road were released approximately 100 yards from their
capture point.
Because the RFID remote detection system failed to work during 2005, location and
status of each animal was determined with handheld receivers once every day. If an
animal was found in a terminal pen, the type of culvert was noted and that event counted
as one crossing. In 2006, the research team used radio telemetry equipment with
stationary scanning receiver- data loggers ( model R4500S; Advanced Telemetry Systems,
Inc., Isanti, Minnesota, USA) to remotely detect and record flat- tailed horned lizard
movement through the culverts, in addition to checking lizard status approximately every
11
third day with handheld receivers. At the rim of the exit ( i. e., distal end) of each crossing
structure, a radio telemetry antenna was buried just under the sand to detect flat- tailed
horned lizards as they passed out of the culvert. Each receiver monitored two culverts.
When a receiver detected a signal, it logged the antenna, time, frequency, and signal
strength. Data were downloaded to a laptop computer in the field.
D. MEASURING TEMPERATURE AND LIGHT INTENSITY
In 2005 one data logger ( Hobo ® pendant temp/ light data logger; Onset Computer
Corporation, Bourne, Massachusetts, USA) was placed on the floor about 15 feet inside
the distal end of each crossing structure to measure light intensity and temperature inside
the culverts every 15 minutes. In 2006 temperature and light intensity data collection
was modified by placing a data logger on the floor midway inside each culvert to take
readings inside the culverts every 60 minutes. In both years, one data logger was placed
outside the culverts to record ambient environmental conditions. These data loggers were
in place for the duration of the field season. To compare conditions between the
simulated crossing structures and culverts actually installed under roadways by ADOT,
temperatures outside and inside three real culverts similar to those in the testing facility
were also sampled in 2006 ( Table 1). Sampled culverts were located under highway US-
95, approximately 23 miles north of the study site. Real culverts installed for water flow
typically passed under the road at an angle, were installed as a pair, and/ or were located
down in a wash. For general comparison, the research team found such dissimilarities
acceptable. Samples were collected over a 24- hour period at each of the three real
culverts. Data loggers were checked to ensure they measured within 2 degrees
Fahrenheit of each other.
12
Table 1. Description of real road culverts selected for temperature comparison to
simulated road crossing structures.
Culvert Width 24- in diameter 36- in diameter 4- ft tall x 8- ft wide
Date placed 9/ 12/ 2006 9/ 14/ 2006 9/ 16/ 2006
Time placed 14: 00 16: 40 11: 50
Date retrieved 9/ 14/ 2006 9/ 16/ 2006 9/ 18/ 2006
Time retrieved 16: 14 11: 13 07: 30
Approximate length ( ft) 68 89 36
Alignment E- W NW- SE E- W
Mean temperature
difference (° F ± SD)
− 2.9 ± 7.1 − 2.6 ± 8.1 − 5.9 ± 8.2
Comments Logger placed on
sand in metal
culvert; mouth a
bit elevated
above the ground
outside; not in a
wash and hasn't
seen water in a
long time.
Two metal
culverts in a
shallow wash,
side by side with
about 12 inches
of dirt between;
logger placed on
sand and rocks
inside north pipe;
it funnels water
but was mostly
dry at the time.
Double side- by-side
concrete box
culvert in a
shallow wash;
logger placed on
sandy gravel in the
north box; box
funnels water, but
it was dry at the
time.
Notes: By subtracting culvert temperature from ambient temperature, mean temperature
difference and range were determined for comparison with simulated culverts.
E. ANALYSIS
Flat- tailed horned lizard use of each of the six culvert types was summarized as a count
of the number of times a lizard crossed through to a terminal pen. The number of
crossings confirmed visually added to the number of likely crossings detected only by the
remote telemetry units. For a description of what the research team considered a “ likely
crossing,” see Appendix A. Low numbers of observations precluded reliable statistical
analysis of lizard crossings.
After the 2005 field season, it was discovered that the 24- inch and 36- inch diameter
culverts did not mimic real culvert conditions because the bulky skylights attached to the
ends blocked more light than they directed into the culvert interior ( Painter and Ingraldi
2005). Because interior lighting and probably airflow in these culverts likely did not
accurately mimic real culvert conditions, 2005 light intensity and temperature data were
dropped from final analyses.
13
In 2006, mean light intensity measurements were compared among all culverts and
ambient values. Temperature measurements were used to calculate the disparity between
ambient and internal culvert temperature, and then the season- long means from the six
simulated culverts were compared. A subset of the temperature discrepancies from the
simulated culverts was also compared to that of the real culverts under highway AZ- 95.
The subset was determined by including only measurements from the simulated culverts
that were taken in the same 24- hour period as that of the real culverts. Each test was
conducted with a one- way ANOVA, and because equal variances could not be assumed,
multiple comparisons were conducted with a Games- Howell post hoc test. All tests were
considered significant at α = 0.05 ( SPSS for Windows, Version 11.5, 2002).
There was one problem with light and temperature data collection in 2006; the data
logger in the simulated 24- inch diameter dark culvert was buried by windblown sand at
some point in the field season. This situation was not discovered until the end of the
season. Light intensity recordings indicated that it was mostly covered by 11 July 2006,
so that data set was truncated, and mean temperature difference of the simulated 24- inch
diameter dark culvert was not compared to that of the real 24- inch diameter culvert.
14
15
IV. RESULTS
A. FLAT- TAILED HORNED LIZARD USE OF EXPERIMENTAL CULVERTS
Arizona Game and Fish Department biologists monitored movements of 54 flat- tailed
horned lizards ( 34 males and 20 females) in the testing facility and observed 12 complete
crossings ( Table 2). Proportionally, there was little difference in use between the sexes;
23% ( eight) of the males used culverts and 20% ( four) of the females used culverts. All
crossing structures except the 24- inch diameter culvert with a skylight were used at least
once ( Table 3). Dark culverts were used more frequently ( nine crossings) than culverts
with skylights ( three crossings). The 36- inch diameter culverts were used most
frequently ( six crossings), and the 24- inch diameter culverts were used least frequently
( two crossings). No individual flat- tailed horned lizard used more than one culvert.
From September through October 2005, at least two of 12 flat- tailed horned lizards made
complete crossings through culverts. From June through September 2006, 42 flat- tailed
horned lizards were monitored in the testing facility. The research team visually
confirmed that six individuals used culverts, and remote telemetry data indicated another
four individuals likely used culverts. During both years, tracks of other species were
found in the culverts, including snakes, ground squirrels, beetles, roadrunners, passerines,
and lizards with long tails.
Not all flat- tailed horned lizards survived 10 days. In 2005, one individual shed its skin
with the transmitter and was lost in the testing facility; a raptor killed another individual.
In 2006 predation in the testing facility became a problem. Predators ( e. g., ground
squirrels, roadrunners, shrikes, or raptors) killed at least 20 flat- tailed horned lizards.
Telemetry signals of another 15 individuals were lost, which was likely a result of raptors
carrying the lizards far away. One individual died of exposure when its transmitter wire
snagged on a stick. Approximate end dates and apparent fates are listed in Appendix B.
Exact survival times were not measured, because the majority of animals were not
visually checked every day.
16
Table 2. Information on each flat- tailed horned lizard used in the simulated road crossing
structure experiment ( 2005- 2006).
ID # Sex Release
date
Culvert use Culvert width
and lighting
Detection method
A M 22- Sep- 05 Yes 4- ft x 8- ft light Visual
B M 22- Sep- 05 Unknown
C M 22- Sep- 05 Yes 24- in dark Visual
D M 22- Sep- 05 Unknown
E M 22- Sep- 05 Unknown
F M 22- Sep- 05 Unknown
2A M 11- Oct- 05 Inside 36D
2B M 11- Oct- 05 Unknown
2C F 11- Oct- 05 Unknown
2D M 11- Oct- 05 Unknown
2E F 11- Oct- 05 Unknown
2F M 11- Oct- 05 Unknown
A1 M 10- Jun- 06 Unlikely
A2 M 10- Jun- 06 Unlikely
A3 F 10- Jun- 06 Unlikely
A4 F 10- Jun- 06 Unlikely
A5 F 10- Jun- 06 Unlikely
A6 F 10- Jun- 06 Unlikely
2B F 12- Jul- 06 Unlikely
4B M 12- Jul- 06 Unlikely
MC1 M 12- Jul- 06 Unlikely
MC3 M 12- Jul- 06 Unlikely
MC5 M 12- Jul- 06 Yes 4- ft x 8- ft light Remote receiver
MC13 F 14- Jul- 06 Unlikely
MC27 M 5- Aug- 06 Unlikely
MC28 M 5- Aug- 06 Unlikely
MC26 F 5- Aug- 06 Unlikely
MC29 F 5- Aug- 06 Unlikely
MC30 F 6- Aug- 06 Yes 36- in dark Visual & remote receiver
MC33 F 8- Aug- 06 Yes 36- in dark Remote receiver
MC47 M 18- Aug- 06 Unlikely
MC42 M 18- Aug- 06 Unlikely
MC46 F 18- Aug- 06 Unlikely
MC45 M 18- Aug- 06 Unlikely
MC43 M 18- Aug- 06 Unlikely
MC44 M 18- Aug- 06 Yes 24- in dark Visual & remote receiver
MC48 M 30- Aug- 06 Yes 4- ft x 8- ft dark Visual & remote receiver
MC49 M 30- Aug- 06 Unlikely
MC50 F 30- Aug- 06 Yes 36- in dark Remote receiver
MC54 M 30- Aug- 06 Unlikely
MC51 M 30- Aug- 06 Yes 36- in dark Remote receiver
Continued.
17
Table 2 ( continued).
ID # Sex Release
date
Culvert use Culvert width
and lighting
Detection method
MC55 M 30- Aug- 06 Unlikely
MC52 F 30- Aug- 06 Unlikely
MC53 M 30- Aug- 06 Unlikely
MC56 M 4- Sep- 06 Unlikely
MC57 F 4- Sep- 06 Unlikely
MC58 M 4- Sep- 06 Yes 4- ft x 8- ft dark Visual & remote receiver
MC59 F 5- Sep- 06 Unlikely
MC60 F 7- Sep- 06 Unlikely
MC61 F 7- Sep- 06 Yes 36- in dark Visual & remote receiver
MC62 M 7- Sep- 06 Yes 36- in light Visual & remote receiver
MC63 M 11- Sep- 06 Unlikely
MC64 F 11- Sep- 06 Unlikely
MC65 M 11- Sep- 06 Unlikely
Notes: Release Date: date the animal was released in the testing facility.
Culvert Use: Yes = crossed all the way through a culvert, Unknown = never observed
using a culvert, Unlikely = probably did not use any culverts because the remote
telemetry detection system did not record a strong signal from their transmitter, or Inside
36D = found inside the 36- in diameter dark culvert.
Detection methods: Visual = lizard visually observed in the terminal pen of a culvert,
Remote receiver = remote receiver detected a crossing, or Visual & remote receiver =
lizard was visually observed in terminal pen and the remote receiver detected the
crossing.
Table 3. Summary of flat- tailed horned lizard use of simulated road crossing structures
( 2005- 2006).
Notes: In 2005, only visual observations of crossings were noted. In 2006, some
crossings were detected only with remote telemetry receivers; some were also verified
with visual observations.
Culvert width
and lighting
2005 visual
detections
2006 remote
detections only
2006 remote detections
verified visually
Total
crossings
24- in dark 1 0 1 2
24- in light 0 0 0 0
36- in dark 0 3 2 5
36- in light 0 0 1 1
4- ft x 8- ft dark 0 0 2 2
4- ft x 8- ft light 1 1 0 2
Sum 2 4 6 12
18
B. TEMPERATURE AND LIGHT INTENSITY
For all simulated culverts, light intensity inside was considerably dimmer than ambient
light intensity ( Table 4). Of the two lighting options at the testing facility, the interior of
all culverts with skylights was brighter than the interior of all culverts without skylights.
Each culvert differed from ambient light intensity and that inside all other culverts
( ANOVA: F6, 8158 = 583.42, P ≤ 0.001; post hoc: all P ≤ 0.017).
Among the simulated culvert temperature discrepancies ( Table 4), within same- size pairs
generally did not differ, but among- size comparisons were generally significantly
different ( F5, 12700 = 97.73, P ≤ 0.001). The only exception was the 24- inch dark culvert,
which differed from its same- size partner, and did not differ from either of the 4- foot by
8- foot box culverts ( Tables 4 and 5).
Table 4. Light intensity and temperature discrepancies at the testing facility ( Jun- Sep).
Culvert width
and lighting
Mean light intensity
( Lumens/ square foot
± SD)
Mean temperature discrepancy
(° F ± SD)
Ambient 2549.8 ± 3437.8 -
24- in dark 1.2 ± 0.5 * 3.4 ± 8.3
24- in light 85.5 ± 104.7 − 0.2 ± 6.6
36- in dark 14.9 ± 95.3 1.5 ± 6.6
36- in light 100.1 ± 121.7 1.5 ± 5.8
4- ft x 8- ft dark 34.1 ± 14.4 3.0 ± 4.5
4- ft x 8- ft light 116.8 ± 76.5 2.7 ± 5.1
Notes: SD stands for ‘ Standard Deviation. Light intensity was averaged over all daylight
hours. Mean temperature discrepancy and range was determined by subtracting culvert
temperature from ambient temperature. * Conditions inside the 24- inch dark culvert
were only averaged through 11 July 2006, because the data logger was likely buried by
windblown sand after that point.
Table 5. Games- Howell test results ( P- values) of multiple comparisons among
temperature discrepancies recorded at simulated culverts.
Culvert width
and lighting
24- in light 36- in dark 36- in light 4- ft x 8- ft
dark
4- ft x 8- ft
light
24- in dark 0.000 0.000 0.000 0.830 0.264
24- in light ------ 0.000 0.000 0.000 0.000
36- in dark ------ ------ 1.000 0.000 0.000
36- in light ------ ------ ------ 0.000 0.000
4- ft x 8- ft dark ------ ------ ------ ------ 0.311
Notes: Bold text denotes a significant difference between means ( α = 0.05). The notable
comparison here is the two 24- inch culverts differed from one another, while the other
same- size pairs did not. Even in a separate comparison between the 24- inch culverts
using data from both sets through 11 July 2006, the means differed ( F1, 1500 = 21, P ≤
0.001).
19
Temperature discrepancy comparisons between real and simulated culverts during a 24-
hour period showed few differences ( F7, 745 = 4.76; P ≤ 0.001). On average, the
temperature discrepancy of the 4- foot by 8- foot real concrete box culvert was 2- 4 degrees
Fahrenheit more than that of other culverts. Mean temperature discrepancy of the 4- foot
by 8- foot real concrete box culvert differed significantly from that of the simulated dark
box culvert ( P ≤ 0.001), the simulated light box culvert ( P = 0.001), the simulated 24- inch
light culvert ( P = 0.001), the real 24- inch culvert ( P = 0.004), and the real 36- inch culvert
( P = 0.005). Mean temperature discrepancy among all other real and simulated culverts
did not differ ( all P ≥ 0.129).
20
21
V. CONCLUSIONS
Although natural conditions inside the testing facility were preserved as much as
possible, the research team acknowledges that the response of each flat- tailed horned
lizard to being placed in a foreign environment likely influenced their behavior. Normal
daily home range movements, migration, dispersal, or breeding behavior may affect an
animal’s propensity to use culverts as actual road crossing structures. The observed low
crossing rate could have been affected by each individual’s reaction to unfamiliar
surroundings, the high density of animals inside the testing facility, presence of predators,
or other factors we did not measure. As the purpose of this study was not focused on
absolute crossing rates, but rather on whether flat- tailed horned lizards would use culverts
and if so what types, the research team agrees that the collected data met the defined
objectives.
Flat- tailed horned lizards can use culverts as road crossing structures, but the evidence
did not reveal a strong selection for or against any culvert type because each size of
culvert was used and both lighting options were used ( Table 3). However, the 36- inch
culverts were used slightly more often than the other sizes, and we observed no use of the
24- inch culvert with skylights. It is possible that more crossings occurred undetected,
especially in 2005 when we relied solely on periodic visual monitoring. Lizards may
prefer to use culverts of an intermediate size. Smith ( 2003) found that herpetofauna in
Florida used culverts most frequently when they were ≥ 59 inches wide and 23- 59 inches
high.
Although mean temperature discrepancy was not the same among all culverts, they were
reasonably close, and all averaged less than 5 degrees Fahrenheit different from ambient
conditions. Unless temperature inside a culvert is drastically different from that outside,
the research team foresees no issues with temperature dissuading flat- tailed horned lizard
use. Lighting inside the 40- foot long experimental culverts may not have affected lizard
selection of culverts, but dark culverts were used slightly more than culverts with
skylights. Culverts longer than 40 feet were not tested in this study, so poor lighting
could be a problem with extremely long culverts, where the center of a small diameter
culvert would be very dark.
Flat- tailed horned lizards did not seem averse to entering culverts. In 2005, at the end of
the summer when lizards were starting to spend more time underground, one individual
was found buried in the sand and mildly torpid a few feet inside the entrance of the 36-
inch diameter dark culvert. In 2006, three flat- tailed horned lizards ( MC44, MC50, and
MC51) were found lingering inside either the 24- inch diameter dark culvert or the 36-
inch diameter dark culvert several hours before passing all the way through. Lizards may
also use culverts as thermoregulatory microhabitat or hiding cover since they provide
vertical structure ( e. g., Rodriguez et al., 1996).
22
Although we did not test whether substrate inside a culvert affects selection, it may be
important for encouraging use, especially in corrugated metal culverts that are slick and
uneven and very different from natural sand or rock. Lesbarreres et al. ( 2004) found that
amphibians select culverts lined with soil as opposed to those of bare concrete. The same
idea of substrate influence may be true for flat- tailed horned lizards.
Characteristics of some culverts changed as time passed. Although light intensity and
visibility from entrance to exit was excellent in the box culverts, strong winds inevitably
swept the sandy soil away from the ends of the culverts, revealing the smooth wood
beneath. If the box culverts had been built 1 or 2 feet into the ground and leveled with
soil, they may have resisted the scouring action of the wind. The real concrete box
culvert also had no soil at the ends, but this was likely due to effects of water flow instead
of wind. The 24- inch diameter culverts seemed particularly susceptible to movement of
the sandy soil. They began filling in with sand quicker than the other culverts, restricting
visibility from entrance to exit. At the real 24- inch diameter culvert, soil had eroded
away from around the ends, leaving the openings above ground level, rendering it useless
as a crossing structure for flat- tailed horned lizards.
23
VI. RECOMMENDATIONS
Because the 24- inch diameter culverts were used less frequently than the larger culverts
and they seemed more susceptible to movement of soil, the research team tentatively
recommends against using these culverts as standard road crossing structures for flat-tailed
horned lizards. While the 36- inch diameter and the 4- foot by 8- foot box culverts
were not immune to movement of sandy soil, they were not as vulnerable as the smaller
culverts. Although the 36- diameter culvert may be the best option, either of the larger
styles could work as a crossing structure, as long as fencing is used to funnel animals
toward the culvert, it remains passable, preferably holds some soil on the floor, and
allows some daylight through its length.
Other issues to consider in designing appropriate road crossing structures include:
regular maintenance ( i. e., maintaining substrate in culverts and ready access to culvert
entrances), how many to install, where to install them, position under the road, and
topography of the crossing site. Although this study showed that in an experimental
situation flat- tailed horned lizards are capable of moving through culverts, they may
exhibit different reactions to culverts under normal circumstances in their own territories
or during typical dispersal. To further test road crossing structures as a viable mitigation
measure for flat- tailed horned lizards, use of actual culverts under roads ( with exclusion
fencing) should be documented for this species in situ.
24
25
VII. BIBLIOGRAPHY
Aresco, M. J. 2005. Mitigation measures to reduce highway mortality of turtles and
other herpetofauna at a north Florida lake. Journal of Wildlife Management
69: 549- 560.
Ascensão, F., and A. Mira. 2007. Factors affecting culvert use by vertebrates along two
stretches of road in southern Portugal. Ecological Research 22: 57- 66.
Brown, D. E., editor. 1994. Biotic communities: southwestern United States and
northwestern Mexico. University of Utah Press, Salt Lake City, Utah, USA.
Dodd, C. K. Jr., W. J. Barichivich, and L. L. Smith. 2004. Effectiveness of a barrier wall
and culverts in reducing wildlife mortality on a heavily traveled highway in
Florida. Biological Conservation 118: 619- 631.
Flat- tailed Horned Lizard Interagency Coordinating Committee. 2003. Flat- tailed
horned lizard rangewide management strategy, 2003 revision. Available at
Arizona Ecological Services Field Office home page.
< http:// www. fws. gov/ southwest/ es/ arizona/>. Accessed 6 Feb 2007.
Lesbarreres, D, T. Lode, and J. Merilae. 2004. What type of amphibian tunnel could
reduce road kills? Oryx 38: 220- 223.
Ng, S. J., J. W. Dole, R. M. Sauvajot, S. P. D. Riley, and T. J. Valone. 2004. Use of
highway undercrossings by wildlife in southern California. Biological
Conservation 115: 499- 507.
Painter, M. L., and M. F. Ingraldi. 2005. Use of simulated highway underpass crossing
structures by flat- tailed horned lizards ( Phrynosoma mcallii). Progress report,
Research Branch, Arizona Game and Fish Department, Flagstaff, Arizona.
Rodriguez, A., G. Crema, and M. Delibes. 1996. Use of non- wildlife passages across a
high speed railway by terrestrial vertebrates. Journal of Applied Ecology
33: 1527- 1540.
Ruediger, B. 2001. High, wide, and handsome: designing more effective wildlife and
fish crossings for roads and highways. Pages 509- 516 in Proceedings of the
International Conference on Ecology and Transportation. Center for
Transportation and the Environment, 24- 28 September 2001, Keystone, Colorado,
USA. Also available at: eScholarship Repository, University of California.
< http:// repositories. cdlib. org/ jmie/ roadeco/ Reudiger2001a>. Accessed 26 Feb 2007.
Smith, D. J. 2003. Monitoring wildlife use and determining standards for culvert design.
Final report presented to the Florida Department of Transportation, Contract
BC354- 34. University of Florida, Gainesville, Florida. Available at < http://
www. dot. state. fl. us/ research- center/ Completed_ Proj/ Summary_ EMO/
FDOT_ BC354_ 34_ rpt. pdf>. Accessed 12 Mar 2007.
SPSS for Windows 2002. Version 11.5. SPSS, Chicago, Illinois, USA.
The Weather Channel [ TWC]. 2007. TWC Interactive home page.
< http:// www. weather. com>. Accessed 22 Jan 2007.
26
Trombulak, S. C., and C. A. Frissell. 2000. Review of ecological effects of roads on
terrestrial and aquatic communities. Conservation Biology 14: 18- 30.
Yanes, M., J. M. Velasco, and F. Suárez. 1995. Permeability of roads and railways to
vertebrates: the importance of culverts. Biological Conservation 71: 217- 222.
27
APPENDIX A. RECORDS AND INTERPRETATION OF FLAT-TAILED
HORNED LIZARD REMOTE TELEMETRY DATA
Appendix A lists the guidelines used in determining if remote telemetry data indicated a
flat- tailed horned lizard crossed through a simulated road crossing structure. The
complete set of remote telemetry data is on file at the Arizona Game and Fish
Department, and is available upon request ( Research Branch, AGFD, 2221 W. Greenway
Rd., Phoenix, AZ 85023; 602- 942- 3000).
We established basic guidelines for interpreting remote telemetry data by evaluating the
signal patterns recorded during visually confirmed crossing events. An example is
presented on the next page. If a flat- tailed horned lizard successfully crossed through a
culvert to the terminal pen, the following general patterns were usually ( but not always)
evident in the antenna and signal strength data:
• The data file had several hundred to a few thousand detections for a single
frequency.
• The data file had many ( e. g., > 40 or 50) detections at an identified antenna within
a few minutes or hours. Detections without an identified antenna were not
convincing.
• A dominant antenna was identified repeatedly in the section where lots of
detections were recorded in a few minutes or hours. The dominant antenna was
the one with a signal strength >> 100, at the same time the subordinate antennas
recorded a signal strength << 100 ( if at all).
• The increase/ decrease in signal strength was more or less steady over time as the
lizard walked past the antenna. A convincing signal pattern would not jump
instantly or repeatedly from a weak signal ( e. g., 60- 70) to a strong signal ( e. g.,
> 115).
28
29
Appendix A ( contd). Example of signal strength recorded by a remote telemetry receiver ( Flat- tailed horned lizard Male MC44). This
example includes all the detections of frequency 150.410- 411 on receiver R2678, which monitored the dark 24- in diameter metal
culvert and the lit 4- ft x 8- ft box culvert from 18- 30 August 2006. The strong signals from the 24- in culvert dominate and cluster at
the top of the line. After the lizard was seen in the terminal pen, he was moved back to the main pen, and the signal faded
accordingly.
40
60
80
100
120
140
160
8
18
8
7
9
18
18
18
19
19
19
20
20
21
21
22
22
23
23
0
0
1
1
2
2
2
3
3
4
4
5
5
16
23
Signal Strength
Time of Day ( hour)
Lizard likely first
crossed 24- in dark
culvert on 8/ 20
Lizard seen in dark
24- in terminal pen
on 8/ 21
Lizard probably remained in terminal pen for about 12 hours before an observer saw it.
30
31
APPENDIX B. SURVIVAL DATA AND FATE OF FLAT- TAILED
HORNED LIZARDS
ID # Release date Approximate end date Apparent fate
A 22- Sep- 05 2- Oct- 05 Lived
B 22- Sep- 05 2- Oct- 05 Lived
C 22- Sep- 05 2- Oct- 05 Lived
D 22- Sep- 05 2- Oct- 05 Lived
E 22- Sep- 05 23- Sep- 05 Shed transmitter
F 22- Sep- 05 2- Oct- 05 Lived
2A 11- Oct- 05 22- Oct- 05 Lived
2B 11- Oct- 05 15- Oct- 05 Predator
2C 11- Oct- 05 22- Oct- 05 Lived
2D 11- Oct- 05 22- Oct- 05 Lived
2E 11- Oct- 05 22- Oct- 05 Lived
2F 11- Oct- 05 22- Oct- 05 Lived
A1 10- Jun- 06 < 21- Jun- 06 Predator
A2 10- Jun- 06 < 21- Jun- 06 Predator
A3 10- Jun- 06 20- Jun- 06 Predator
A4 10- Jun- 06 < 21- Jun- 06 Predator
A5 10- Jun- 06 < 21- Jun- 06 Predator
A6 10- Jun- 06 < 21- Jun- 06 Predator
2B 12- Jul- 06 14- Jul- 06 Predator
4B 12- Jul- 06 14- Jul- 06 No signal
MC1 12- Jul- 06 14- Jul- 06 No signal
MC3 12- Jul- 06 23- Jul- 06 Lived
MC5 12- Jul- 06 21- Jul- 06 No signal
MC13 14- Jul- 06 18- Jul- 06 Predator
MC26 5- Aug- 06 17- Aug- 06 Lived
MC27 5- Aug- 06 7- Aug- 06 No signal
MC28 5- Aug- 06 16- Aug- 06 Died intact
MC29 5- Aug- 06 7- Aug- 06 No signal
MC30 6- Aug- 06 14- Aug- 06 Predator
MC33 8- Aug- 06 9- Aug- 06 Predator
MC42 18- Aug- 06 20- Aug- 06 Predator
MC43 18- Aug- 06 22- Aug- 06 No signal
MC44 18- Aug- 06 22- Aug- 06 Predator
MC45 18- Aug- 06 22- Aug- 06 Predator
MC46 18- Aug- 06 19- Aug- 06 No signal
MC47 18- Aug- 06 20- Aug- 06 No signal
MC48 30- Aug- 06 1- Sep- 06 No signal
MC49 30- Aug- 06 1- Sep- 06 Predator
MC50 30- Aug- 06 8- Sep- 06 Lived
MC51 30- Aug- 06 1- Sep- 06 No signal
Continued.
32
Appendix B ( contd).
ID # Release date Likely end date Fate
MC52 30- Aug- 06 1- Sep- 06 Predator
MC53 30- Aug- 06 1- Sep- 06 Predator
MC54 30- Aug- 06 2- Sep- 06 No signal
MC55 30- Aug- 06 31- Aug- 06 Predator
MC56 4- Sep- 06 6- Sep- 06 No signal
MC57 4- Sep- 06 5- Sep- 06 Predator
MC58 4- Sep- 06 13- Sep- 06 Lived
MC59 5- Sep- 06 14- Sep- 06 Lived
MC60 7- Sep- 06 16- Sep- 06 Lived
MC61 7- Sep- 06 13- Sep- 06 Predator
MC62 7- Sep- 06 13- Sep- 06 No signal
MC63 11- Sep- 06 13- Sep- 06 No signal
MC64 11- Sep- 06 12- Sep- 06 Predator
MC65 11- Sep- 06 12- Sep- 06 No signal
Arizona State Government Publications
