The biters and the bitten: snake management in Victoria › marketing › assets › pod... · The...

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The biters and the bitten:

snake management in Victoria

Nick Clemann Arthur Rylah Institute for Environmental Research

Department of Environment and Primary Industries, Heidelberg

Arthur RylahInstitute

Flora, Fauna &Freshwater Research

Who am I?

Threatened Fauna Program Leader Arthur Rylah Institute

Dep’t Environment & Primary Industries (Heidelberg)

Most of my work is in Victoria, but have worked in Uzbekistan, USA, Argentina, Kazakhstan

What we’ll cover today

•  The human side of human-snake interactions

•  Common Victorian snakes – identification challenges

•  What happens to relocated snakes - radiotracking

•  Snakebite

Threatened wildlife 1

Augmentation

(Spotted Tree Frogs, Mt Pygmy Possums)

Reintroductions (BT Rock Wallaby)

Relocating nuisance /

dangerous wildlife

Magpies Possums

Kangaroos Bees

SNAKES

Threatened wildlife 2

Ad hoc relocations

(Growling Grass Frogs, Striped Legless Lizards

Translocation – a generic term

Snakes have had a bad rap ever since that little incident with the apple in the Garden

of Eden…

Of all animals encountered in suburbia, snakes were the least desired around homes Davies, R.G., Webber, L.M. and Barnes, G.S. (2004). Urban wildlife

management – it’s as much about people! In: Urban Wildlife: More Than Meets the Eye. Eds Lunney, D. & Burgin, S. Royal Zoological Society of New South Wales.

Australia’s snake fauna is unique – and not in ways that make them

endearing

European invaders learnt early that the potential for many Aussie species to kill was unmatched

anywhere on Earth…

“I may mention that the bite of most of them in that country is almost instantaneously fatal”

Alexander Marjoribanks 1840 WRT Botany Bay

“If a snake bites you in this country, instant death follows. One of the most deadly and common snake’s bite is so bad that the person bit only shivers and falls dead immediately”

William Coke 1827

•  ~ 60 licensed catchers in Victoria (~35 in greater Melb / Geelong areas)

•  Current strategy - capture and relocation

5 km or less

Victorian snake management

DEPI permit: release “on public land within 5km of capture”

Scale of relocations?

Fate of snakes?

Impact at both donor & release sites?

2 key issues:

Human dimensions opinions, biases, motivations, knowledge and behaviours of people and organisations involved in human-snake conflict

Biological / ecological implications of translocating snakes effects of capture / relocation on individuals,

impacts on conspecifics and other species at both the “donor” and release sites

Human dimensions

We* conducted questionnaire surveys of:

1.  Licensed snake catchers (n = 45)

2.  Residents (n = 225?) - won’t cover this today

*Clemann, N., McGee, T. and Odgers, J. (2004). Snake management on private properties in

Melbourne, Australia. Human Dimensions of Wildlife 9(2): 133-142.

Clemann, N. (2006). Practices, experiences and opinions of snake catchers and their clients in southern Australia. The Victorian Naturalist 123(6): 383-389.

Snake catcher’s questions

•  Number of call-outs / year?

•  % calls resulting in capture?

•  Months with highest number of calls?

•  Species involved?

•  Single or multiple release sites?

•  Criteria used to choose release sites?

Results - Snake catchers (n=14)

•  Call-outs / year: ~ 50 - 60 (ra. 2 – 550 / year)

•  Proportion resulting in capture: ~50 - 70% (ra. 30 - 100% - one catcher translocates 300 / season!)

•  Est. 1000 – 2000 translocated around Melb / Geelong each year

Months of calls received to remove snakes

024681012

September

October

November

December

January

FebruaryMarch Ap

Snake species caught by licensed controllers

101214

Tiger S

Copperh

Easter

n Brown S

Red-bell

ied Blac

Other s

pecies

Geographic trends

Tiger Snakes predominate N, W and SW of Melbourne

Copperheads to the E and SE

Snake catchers

How far are snakes moved? – Most < 5 km (as per permit)

– others 10 – 50 km

Sites used for release: – “crown land within 5 km”

– Parks / reserves (e.g., Braeside Pk)

– “no comment” - 300 snakes / year

2 use same release site (incl. the one who releases 300 / season!)

11 use different sites – based on location of capture or species

involved

– some mentioned fear of “overpopulating” release sites

Snake catchers

How are release sites selected?

–  “5 km radius of capture”

– as far from residents as possible

– as close to capture site as possible

–  “suitable habitat” - rocks, water, food, few predators etc.

– where other snakes observed

•  Large scale, ongoing issue

•  Current strategy not a permanent solution – most residents have to call in catchers

numerous times

•  People taking matters into their own hands? –  risk of being bitten

– breaking law

Tiger Snake Notechis scutatus

photographs by Peter Robertson

Lowland Copperhead Austrelaps superbus

Highland Copperhead Austrelaps ramsayi

Photographs by Peter Robertson

Eastern Brown Snake Pseudonaja textilis

www.snakecatchers.com.au

www.australianmuseum.net.au

Red-bellied Black Snake Pseudechis porphyriacus

White-lipped Snake Drysdalia coronoides

Effects of relocation on Tiger Snakes - spatial ecology / activity patterns

What happens to relocated snakes? A radio-tracking study

Butler, H., Malone, B. and Clemann, N. (2005). The effects of translocation on the spatial ecology of tiger snakes (Notechis scutatus) in a suburban landscape. Wildlife Research 32, 165-171.

Butler, H., Malone, B. and Clemann, N. (2005). Activity patterns and habitat preferences of resident and translocated tiger snakes (Notechis scutatus) in a suburban landscape. Wildlife Research 32: 157-163.

Clemann, N. and Butler, H. (2005). Venom ‘spitting’ during handling in an Australian elapid snake. Herpetofauna 35(2): 83-84.

Clemann, N. and Butler, H. (2006). Carrion scavenging by the Tiger Snake Notechis scutatus. Herpetofauna 36(1): 2-4.

Clemann, N., Butler, H. and Malone, B. (submitted). Thermal biology of tiger snakes (Notechis scutatus) in a suburban parkland in south-eastern Australia: a radio-telemetric study of translocated and resident snakes. Journal of Thermal Biology

Most previous research on relocated snakes from Nth America (mainly Rattlesnakes – major ecological differences to Australian snakes)

Westerfolds Park 123 ha urban

parkland ~15 km E of Melbourne

460-559 560-659 660-759 760-859 860-959 960-1059

Snout-vent length (mm)

Size of Tiger Snakes caught at Westerfolds Park

Transmitter size meant we needed snakes 760 mm snout-vent length ≥

•  Resident snakes (2F / 4M) caught at Westerfolds

•  Relocated snakes (4F / 4M) caught by snake catchers within 5 km of study site

•  Catchers asked not to release at Westerfolds prior to / during study

Challenges of fitting transmitters to beasts that lack limbs and a defined neck…

•  Following surgery / recovery, residents released at capture point

•  Relocated snakes released at random points in “suitable habitat”

•  Tracked 2 - 5 times / week

3 estimates of home range

100% Minimum Convex Polygon (MCP)

95% Harmonic Mean (Home Range)

50% Harmonic Mean (Core Range)

MCP (ha ± 1SE) 95% HM ‘Home Range’

50% HM ‘Core Range’

Residents 3.30 ± 2.07 4.30 ± 1.769 0.957 ± 0.299

Trans. 19.45 ± 9.764 25.36 ± 8.125 1.331 ± 0.385

Range:

t = -1.731 d.f. = 11

P = 0.111

t = -2.805 d.f. = 11

P = 0.017

t = -0.748 d.f. = 11

P = 0.470

Residents Trans.

13.2 62.8

11.5 59.6

1.8 2.7

October November December January February March

Residents

Translocated

Frequency of movements ( 5 m) ≥

October November December January February March

Residents

Translocated

) Distance per movement

Relocated snakes - large initial movements, then continue to move more than twice as far as residents

(mean 140 vs. 64 m, 2-way ANOVA with month and

group as the factors, F1,273 = 9.605, P = 0.002)

•  Half the relocated snakes left park, crossed Yarra River, entered adjacent private properties

•  Some property owners not happy about this...

•  When returned back to the park, several snakes returned to these properties

• Relocation did affect snakes –  Animal welfare issues? –  Spread of disease / parasites? –  Genetic considerations? –  Impact on conspecifics, competitors, predators, prey,

humans…?

• Potentially moving human-snake conflict from one area to another –  Liability issues?

• What happens over other seasons / study sites / to other species?

• Worth trialing alternative management, such as short-distance relocation or “Living with Snakes”?

Heath shows his bitten finger, and thanks the staff of the Austin Hospital for effective treatment...

Good students are hard to come by…try not to let them die!

Source: Shine 1991

Red-bellied Black Snake Pseudechis porphyriacus

Eastern Brown Snake Pseudonaja textilis

Source: Shine 1990

Tissue necrosis following a bite from a South American Terciopelo

(Bothrops asper )

Source: Shine 1991

With the recent discovery of a new Taipan, approximately 80% of the snakes thought to be the most deadly on Earth occur in Australia

Snakebite management

•  Be prepared – how many ‘snake’ bandages do you have? (Setopress bandages best)

•  Don’t panic…at least not for long…

•  Do not wash the bite sight – swabs can be used by doctors to identify the snake

•  Both parts of ‘Pressure-Immobilisation’ 1st Aid technique are vital

Snakebite management

•  No wandering around – bring transport to the victim

•  Once bandaged, immobilise limb any way you can

•  What if bite is on face / neck? What if I’m a hundred miles up a track with no vehicle and communications?

Immediately: If others are present, have someone phone for medical assistance. If unable to phone, send someone for help.

Reassure the patient and encourage them to remain calm and still.

Applying a pressure immobilisation bandage

As soon as possible, apply a broad pressure bandage from below the bite site, upward on the affected limb (starting at the fingers or toes, bandaging upward as far as possible). Leave the tips of the fingers or toes unbandaged to allow the victim’s circulation to be checked. Do not remove pants or trousers, simply bandage over the top of the clothing.

Bandage firmly as for a sprained ankle, but not so tight that circulation is prevented. Continue to bandage upward from the lower portion of the bitten limb.

Apply the bandage as far up the limb as possible to compress the lymphatic vessels.

Bind the splint firmly, to as much of the limb as possible, to prevent muscle, limb and joint movement. This will help restrict venom movement. Seek urgent medical assistance now that first aid has been applied.

First Aid for Bites on the Hand or Forearm 1 As soon as possible, apply a broad pressure bandage from the fingers of the affected arm, bandaging upward as far as possible. Bandage the arm with the elbow in a bent position, to ensure the victim is comfortable with their arm in a sling. Leave the tips of the fingers unbandaged to allow the victim’s circulation to be checked. 2 Bind a splint along the forearm. 3 Use a sling to further prevent limb movement.

It is vital to now apply a splint. Bind a stick or suitable rigid item over the initial bandage to splint the limb. Secure the splint to the bandaged limb by using another bandage, (if another bandage is not available, use clothing strips or similar to bind). It is very important to keep the bitten limb still.

Source: Australian Venom Research Unit

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