DESERT TORTOISE SIGN RECOGNITION · 2019. 6. 27. · DESERT TORTOISE SIGN RECOGNITION DESERT TORTOISE SIGN RECOGNITION 5 BURROW CLASSES Class 3- Poor: Substantial structural degradation,

DESERT TORTOISE SIGN RECOGNITION

DESERT TORTOISE SIGN RECOGNITION 1


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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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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Relative Frequency of Tortoises Found in Burrows and in Open

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2001 2001 2002 2002 2003 2003 2004 2004 2005 2005 2007 2007 2008 2008YEAR AND OBSERVATION TYPE

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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!



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



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



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


  Fox Burrow –  Trail on mound and

into burrow –  Vertical rise at base –  Tracks


  Badger Burrow –  Claw marks on burrow

walls –  Vertical rise at base


  Kangaroo Rat burrow - in sandy soils the sides collapse



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



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



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



CAUSE OF DEATH

  Look at situation prior to intrusion

  Search entire site, parts may be scattered

  Most will be unknown



  Left - Entrance wound

  Right - Exit wound, note concoidal fracture



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



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



ANOMALOUS TORTOISE



EXTERNAL PARASITES

INJURIES

DOGS

  Have Nothing but Time and Energy   Substantial Risk to Desert Tortoises   Other Wildlife   And People



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

Documents

DESERT TORTOISE SIGN RECOGNITION · 2019. 6. 27. · DESERT TORTOISE SIGN RECOGNITION DESERT TORTOISE SIGN RECOGNITION 5 BURROW CLASSES Class 3- Poor: Substantial structural degradation,