Movement patterns of Western Diamondback Rattlesnakes (Crotalus atrox) at Bosque del Apache National Wildlife Refuge, New Mexico

Presented by Lorraine McInnes

Photo taken by Greg Wright

Research Objectives

1) Describe rattlesnake movement patterns at

Bosque del Apache?

2) Do movement patterns and hibernacula differ

between riparian and upland habitat?

Project Tasks

Spatial Distributions

Data analysis:

Season and Gender variation, response to Temperature and

Moisture fluctuationsHabitat usage

Data Organization

Vicinity Map

Old

Vicinity Map

New

Distribution

Animal MovementsCreate Minimum Convex PolygonsCalculate Movement ParametersConvert Locations To Paths

Success!!

18 snakes-Routes and Home Range outputs

The wonders of Viewing the Full Extent

Data Editing

To get those results:

Many repetitions, changes in excel and arcmap

Learned many lessons on how to organize this kind of data

Currently:

Have an up to date, edited data file

Simplified, step by step repeatable process to get weekly movement results.

Data

Average size, all snakes (n=18): 31 ha, range 2-81 haAverage size, male (n=11): 35.2 ha, range 5-81 haAverage size, females (n=7): 24 ha, range 2-61 ha

SBDAERR

Sandog

Six S

tall

Bridge

Toile

tte

MLo

opOLD

LFRdNew

S

FeeB

ooth

Fire

shop

Hwy1To

ol

RR Tre

stle

Chucky

Hwy1Mar

sh

Spike

Smok

ey

Hwy1SVC

Mar

shLo

opS

Exit

0

10

20

30

40

50

60

70

80

90

Minimum Convex Polygon-Home Range Area

Hect

are

s

Male

Female

Data

Name Average Distance Total Dist (m) RangeNo Move Days Total Days

Bridge 170.5 1534.5 41.2-382.3 15 24Chucky 55.5 4993.7 1.9-343 78 168Exit 97.9 6901.3 2.2-736.7 23 96Feebooth 59.1 5576.1 3.9-317.5 55 151Fireshop 64.2 4363.7 4.4-612.5 41 110Hwy1Marsh 68.0 4965.8 2.4-167.8 94 168Hwy1SVC 72.0 6980.9 1.1-541.9 169 267Hwy1Tool 84.5 8872.6 1.9-338.1 63 170LFRdNewS 67.9 4754.2 4.3-298.4 90 162MarshLoops 125.6 12053.0 1.4-715.6 63 161MLoopOLD 84.7 2712.0 1.4-435.2 42 76RR Trestle 80.1 7292.4 3.5-390.1 78 171Sandog 97.2 1360.2 2.2-476.9 38 54SBDAERR 31.1 1741.1 1.9-290.2 102 158Six Stall 70.0 3150.6 2.4-241.1 59 106Smokey 96.4 6938.5 5.8-780.8 30 103Spike 123.4 8266.5 2.4-414.7 60 128Toilette 76.1 4108.5 .9-537.4 64 120

Visualizing Snake Movement

Annual Cycle

Next step:

Activity Clustering

Statistical Analysis of Movements to describe movement differences by habitat, season, and gender

*Revisit Spatial Statistics and Regression Analysis Virtual Courses

Road Crossing

Hwy 1 and/or RR was crossed 81 times.

Hwy1Tool-crossed road or tracks 22 times.

Next highest number of crossings: 12

Trials and Tribulations

ArcScene-3D animation

Animation in general

Habitat-spatial join…veg type text to numeric value?!

Hawth’s Tools-route issues continue

Continued Work

Refine movement parameters and generate more descriptive statistics

Animate certain routes to better visualize movement, 2D, 3D-Flythrough tour

Generate habitat use spatial join to determine which habitats the snakes were used more than others

Field work: Characterize new dens and determine site preference based on various parameters-slope, aspect, elevation, proximity to roads, water, man-made structures, etc.

Den Site Suitability model

Questions??