desert tortoise sign recognition · 2019. 6. 27. · desert tortoise sign recognition desert...
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DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 1
DESERT TORTOISE SIGN RECOGNITION
INITIAL REQUIREMENTS Know and Understand USFWS Requirements for Desert Tortoise Surveys – Download, Read, Understand New USFWS Survey Requirements – 100% Coverage – Appropriate Time of Year – Appropriate Temperatures – When Appropriate, Walk Transects in the Zone of Influence
Must Find the Project Site – Client Must Provide Good Maps and UTM Coordinates – Know How to Use Your Equipment (GPS Unit, Thermometer, Maps)
INITIAL REQUIREMENTS Concentrate on the Task
– Minimize Distractions – E.g. Talking, Phone Calls, etc. – More Difficult Keeping Concentration in Areas of Low Density but it is
vital to find some of the few sign that may be available
Data From Line Distance Transects – Shown that Live Adult Tortoises are Missed When Fieldworkers are Three
Meters from Each Other – Burrows and Scat are Much More Difficult to Find
Must be Able to Recognize Desert Tortoise Sign
Find Sign in the Open
And Under Cover LINE DISTANCE TRANSECTS - LIVE
TORTOISE ENCOUNTERS Top - Tortoises > 180 mm
MCL Lower - All Tortoises
Adult Tortoises were Missed at < 1.5 m
Live Tortoises more visible than Scats and Burrows
At 8 meter intervals about 70% of adult tortoises are located
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0-1.4 1.5-2.9 3-4.4 4.5-5.9 6-7.4 7.5-8.9 9-10.4 10.5-11.9 12-13.4 13.5-14.9 15-16.4 16.5-18PERPENDICULAR DISTANCE
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FollowLead
0
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0-1.4 1.5-2.9 3-4.4 4.5-5.9 6-7.4 7.5-8.9 9-10.4 10.5-11.9 12-13.4 13.5-14.9 15-16.4 16.5-18PERPENDICULAR DISTANCE
FREQ
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Y
FollowLead
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 2
Relative Frequency of Tortoises Found in Burrows and in Open
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
FOC
AL
TRA
N
FOC
AL
TRA
N
FOC
AL
TRA
N
FOC
AL
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FOC
AL
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N
FOC
AL
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FOC
AL
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N
2001 2001 2002 2002 2003 2003 2004 2004 2005 2005 2007 2007 2008 2008YEAR AND OBSERVATION TYPE
REL
ATI
VE F
REQ
UEN
CY
BURROW SHRUB OPEN
NOT ALL SIGN ARE VISIBLY EQUAL
Easy - Tortoise and burrow
Not so Easy - Trail to burrow, dark scat on cobble
Cryptic - Old gray scat on light cobble or dark scat on dark cobble
SEARCH HABITAT THOROUGHLY
Spend 75-80% of search time within 2.5 meters
Tighten interval between searchers as needed
Search in front and behind you
Search under and thru shrubs Keep search image of
tortoise, scat, and burrow shapes in mind
CONCENTRATE!
SEARCH HABITAT THOROUGHLY
SEARCH BURROWS THOROUGHLY
Do what is necessary to search burrows thoroughly Use bright flashlight or mirror Use probe if needed (if you have your Permit!)
BE CAREFUL!
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 3
LOW DENSITY AREAS
Never assume tortoises are not present!
Always be diligent Fewer rewards but of no less importance Your confidence will be deflated now and then
TYPES OF SIGN
IN ORDER OF FREQUENCY – Scat – Burrows – Carcasses – Live Tortoises – Drinking Depressions – Tracks – Eggs or Eggshell Fragments
SCAT
Shaped like a short cigar May be straight, a crescent, tapered ends or not, but not serrated or twisted Material generally large-not chewed Material generally oriented linearly
Variety of colors Age from dark to light Aging: Current year/Not Current Year
GEOPHAGUS SCAT IS IT TORTOISE?
Top - Chuckwalla
Bottom - Desert Iguana
Check: Odor, Shape, Particle Alignment, Location
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 4
OR IS IT NOT TORTOISE?
Top - Sheep
Bottom - Burro
Check: Particle size and alignment, shape
SHEEP Typically in Flocks Large Areas of Impact Bedding Areas and Many Scat
BURROW
Shaped like a half-moon Flat bottom Sides angle directly from the floor Well-rounded, clean (no rocks) mound
BURROW CLASSES
Class 1 - Active: tortoise or tracks present
BURROW CLASSES
Class 1 - Active: tortoise or tracks present Class 2 - Good: No structural degradation, a tortoise could just walk in
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 5
BURROW CLASSES
Class 3- Poor: Substantial structural degradation, much effort needed to use the burrow
BURROW CLASSES POTENTIAL TORTOISE
Class 4 - Good condition Class 5 - Poor condition
IS IT A TORTOISE BURROW?
Yes! - Look back in the tunnel for the actual shape - or for a tortoise
IS IT A TORTOISE BURROW?
Fox Burrow – Trail on mound and
into burrow – Vertical rise at base – Tracks
IS IT A TORTOISE BURROW?
Badger Burrow – Claw marks on burrow
walls – Vertical rise at base
IS IT A TORTOISE BURROW?
Kangaroo Rat burrow - in sandy soils the sides collapse
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 6
JUVENILE TORTOISE BURROW
May use rodent burrows when very small Will dig their own burrows when very young Check for tracks in tunnel Search surrounding area for more burrows and tortoise
TORTOISE TRACKS
Seen only in soft soil Two rows of footprints Use toenail marks to determine direction of travel
GEOPHAGUS SITES
Often under surface of desert pavement Soil on beak will be dry and not embedded in scales
GEOPHAGY SITES
Often under surface of desert pavement Or along washbanks
DRINKING DEPRESSIONS
Always in areas with fine soils Commonly at base of a rock Tortoise will eat mud or suck up water thru nares Not in typical sandy or loam soils
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 7
TORTOISE EGGS
Size of ping pong balls Are oval, round, or elongate
TORTOISE NESTS
May be in the open Generally associated with a burrow
CARCASSES
Two Main Objectives – Estimate Time Since Death – Determine Cause of Death
Amount of Disarticulation of Scutes or Bones has Nothing to do with Time Since Death
Look Thru Coyote Scats
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 8
TIME SINCE DEATH
Based on amount of weathering of scutes and bones Use most weathered portions Categories
– < 1 year (all parts have sheen and luster) – 1 - 2 years (bones and scutes faded, no luster) – 2 - 4 years (scutes faded, may be cracked and curling;
bones faded, may be pinholes or superficial cracks – > 4 years (scutes very weathered, bones deossifying,
layers of collagen cracked and peeling)
Juveniles age more rapidly than adults, in a separate portion of the key Note lack of ossification Completely ossify at 7 to 10 years (90 to 110 mm) Less than one year time since death
Left - < 1 year (bones, scutes, and scales are glossy)
Right - 1-2 years (scutes, tightly adhered, are fading
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 9
CAUSE OF DEATH
Look at situation prior to intrusion
Search entire site, parts may be scattered
Most will be unknown
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 10
Left - Entrance wound
Right - Exit wound, note concoidal fracture
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 11
LIVE DESERT TORTOISE
Size Sex Health Status
– Weight – Parasites – URTD Signs – Shell/bone Abnormalities – Injuries
No Permit - No Harrass!!!
CARAPACE
Nuchal Marginals (11 each side [Peripherals]) Pygal Costals (4 each side) Vertebrals (5)
PLASTRON
Gulars Humerals Pectorals (Pleurals) Abdominals Femorals Anals
LENGTH
Length = MCL – Maximum or Midline
Carapace Length Straight-line distance from nuchal to pygal
WEIGHT
Use medium-weight string, dental floss, plastic bag, etc. Always keep hand under the tortoise Pesola scales are the most consistent Long throw for accuracy
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 12
STERILIZE
Sterilize all equipment that contacts tortoise
Use 20% solution (bleach or chlorine-based solution)
Change solution weekly
MALE
Long Tail Concave Plastron Long Gular Usually Larger Chin Glands
FEMALE
Short Tail Flat Plastron Short Gular Longer Rear Nails Small Chin Glands
HATCHLING
Hatchling Plate or Areola
Gray Material is New Growth
JUVENILE
Few Growth Annuli
Note New Growth from Previous Spring
Annuli deposition is when a tortoise grows, not annually
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 13
ANOMALOUS TORTOISE
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 14
EXTERNAL PARASITES
INJURIES
DOGS
Have Nothing but Time and Energy Substantial Risk to Desert Tortoises Other Wildlife And People
DESERT TORTOISE SIGN RECOGNITION
DESERT TORTOISE SIGN RECOGNITION 15
IN CONCLUSION
Know and Recognize Sign CONCENTRATE - Sign is easy to miss Recognize Normality - Behaviors, Morphology, Health Signs Document Photograph Ask Questions (USFWS, CDFG, BLM) Distribute Data and Information
Thank you
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