"On The Edge"

Shoot 1
Film 1
(30 minutes)

April 30th-May 17th 2000

Location of OBA film 2:1
New South Wales

(mouse-over for view of southern New South Wales)


Hoplocephalus bungaroides

The Broad-headed snake (Hoplocephalus bungaroides) is one of Australia's rarest and most threatened snakes. One of three species in the genus Hoplocephalus*, it exhibits the most limited range, being confined to the Hawkesbury sandstone ridges and bluffs around Sydney, as far inland as the Blue Mountains and south to Nowra.

Sydney, the state capital of New South Wales, was established in 1788. In the 200+ years since it has expanded to become the most populous city in Australia with an area of 12,145 sq.kms. and a population of over 4.5 million. A great deal of broad-headed snake habitat will have been devoured during that time.

Today this is a protected species but it is still in danger, directly from illegal collection and indirectly by the harvesting of "bush rock", itself an illegal practise for the ornamental gardens of the metropolis. Broad-headed snakes are found under flat slabs of the Hawkesbury sandstone bedrock of Sydney and its environs, but always in rock on rock, never rock on soil, situations, and often near the edge of steep cliff-faces. Prey consists of the geckos and skinks that inhabit the same habitat, especially Lesueur's velvet gecko (Oedura lesueurii). During summer they climb into eucalypt trees.

Achieving 0.9 m in length, this relatively small but also highly venomous species gets is name from the defensive tactic of flattening its head when under threat (see image below). The broad-headed snake is listed as Vulnerable on the IUCN Red Data List and is considered Endangered in New South Wales.

Much of the work on this species was conducted by Jonathan Webb when he worked in the Rick Shine Lab at the University of Sydney (see citations below for more information).

Shine, R. 1983 Arboreality in snakes: Ecology of the Australian genus Hoplocephalus. Copeia 1983:198-205.

Shine, R., J.K. Webb, M. Fitzgerald & J. Sumner 1998 The impact of bush-rock removal on an endangered snake species Hoplocephalus bungaroides (Serpentes, Elapidae). Wildlife Research 25:285-295.

Webb, J.K. & R. Shine 1997 A field study of spatial ecology and movements of a threatened snake species, Hoplocephalus bungaroides (Serpentes, Elapidae). Biological Conservation 82:203-217.

Webb, J.K. & R. Shine 1997 Out on a limb: conservation implications of tree-hollow use by a threatened snake species (Hoplocephalus bungaroides: Serpentes, Elapidae) Biological Conservation 81: 221-33.

Webb, J.K. & R. Shine 1998 Thermoregulation by a nocturnal elapid snake (Hoplocephalus bungaroides) in southeastern Australia. Physiological and Biochemical Zoology :680-692.

Webb, J.K. & R. Shine 1998 Ecological characteristics of a threatened snake species, Hoplocephalus bungaroides (Serpentes, Elapidae). Animal Conservation 1:185-193.

Webb, J.K. & R. Shine 1998 Using thermal ecology to predict retreat-site selection by an endangered snake species. Biological Conservation 86: 233-242.

Webb, J.K. & R. Shine 2000 Paving the way for habitat restoration: can artificial rocks restore degraded habitats for endangered reptiles? Biological Conservation 92:93-99.

Webb, J.K., B.B. Brook & R. Shine 2002 Collectors endanger Australia's most threatened snake, the broad-headed snake Hoplocephalus bungaroides. Oryx 36(2):170-181.

Webb, J.K., B.B. Brook & R. Shine 2002 What makes a species vulnerable to extinction? Comparative life history traits of two sympatric snakes. Ecological Research 17:59-67.

* The Pale-headed snake (H.bitorquatus) occurs over a wide area from northeastern New South Wales to eastern-central Queensland, while Stephens' banded snake (H.stephensii) exhibits a more limited range along the coast of northern New South Wales and southern Queensland. Both the ranges of these species lie to the north of Sydney and the range of the broad-headed snake.


Broad-headed snake, Hoplocephalus bungaroides


Hadronyche versuta

The Sydney funnel-web spider (Atrax robustus) is one of the most famous and feared spiders in the world, which is hardly surprising because it is both aggressive and highly venomous, the possessor of a virulent neurotoxin known as Atraxotoxin, males possessing up to six-times more venom than females. The 160 km radius-range of the Sydney funnel-web is much larger than people realise, extending from Nowra to Newcastle and inland to Lithgow and Oberon, and it is a common inhabitant of suburban gardens and semi-rural areas, especially wet schleophyll forests and rainforest habitats. They shelter on the ground under rocks and logs. Antivenom is produced for the bite of the Sydney funnel-web spider, almost entirely manufacturered using spiders housed and 'milked' at the Australian Reptile Park (ARP). No fatalities have been recorded since the advent of antivenom in 1981, but 13 earlier deaths are believed attributable to male Sydney funnel-webs.

But this is not the only species of funnel-web in eastern Australia. Although Atrax is a monotypic genus, there is a second genus of funnel-webs, Hydronyche - the tree funnel-webs, a genus of at least 15 species occuring through eastern Australia and into New Guinea and the Solomon Islands. Several species occur in New South Wales, and one, the Blue Mountain funnel-web (H.versuta) in the mountains for which is it named, but also as far east as Sydney and west as Bathurst and Orange. This is considered one of at least six species capable of delivering a life-threatening bite. As people move into these more remote habitats, either as walkers or settlers, they are increasingly likely to come into contact with tree funnel-webs and bites do occur. Antivenom for Atrax robustus is effective in the treatment of bites from Hydronyche spp. (Graudins et al 2002) but supplies are limited (Miller et al 2000).

Our aim was to obtain males of the Blue Mountain funnel-web spider for the on-going antivenom production program based out of ARP. This film pre-dated both of the following papers.

Graudins, A., D. Wilson, P.F. Alewood, K.W. Broady & G.M. Nicholson 2002 Cross-reactivity of Sydney funnel-web spider antivenom: neutralization of the in vitro toxicity of other Australian funnel-web (Atrax and Hadronyche) spider venoms. Toxicon 40(3):259-266.

Miller, M.K., I.M. Whyte, J. White & P.M. Kier 2000 Clinical features and management of Hadronyche envenomation in man. Toxicon 38(3):409-427.

Blue Mountain tree funnel-web spider, Hydronyche versuta


Distribution of the Broad-headed snake,
Hoplocephalus bungaroides,
in New South Wales
Distribution of the Blue Mountain tree funnel-web spider,
Hadronyche versuta,
in New South Wales
Click on map to enlarge


Map of Sydney and northern expedition area, showing primary and secondary locations
(click on map for enlarged view)
Map of Nowra and southern expedition area, showing primary and secondary locations
(click on map for enlarged view)

Facts about Hawkesbury Sandstone
(sources Wikipedia and others)

Hawkesbury sandstone, also known as "Yellowrock", is a sedimentary sandstone named after the Hawkesbury River north of Sydney. It is the rock much of Sydney and neighouring towns is build from and on. Many of the monuments, churches, galleries, museums, banks, commercial and public buildings were contructed from this rock, especially those during the period of Sydney's early growth from 1790-1890. By the mid-20th Century the demand for buildings out of quarried sandstone began to diminish but it became a fashionable accessory in thousands and rock gardens and water-features in the suburbs. Rather than quarried stone from regulated commercial quarries, the "bush rock" used in gardens came from the bush, much of it collected by the landscape gardeners themselves. This uncontrolled and unregulated collection of flat slabs of rock from the bush was seen as a threat to the wildlife that lived in those habitats, including the Broad-headed snake (Hoplocephalus bungaroides). A comparison might be drawn with the collection of Saguaro cactus (Carnegiea gigantea) to adorn desert gardens in Arizona, USA and in teh same way that the Arizona authorities made collection of saguaro cacti illegal, several councils in New South Wales erected signs clearly stating that
"Bushrock removal is prohibited".

Facts about the Blue Mountains
(sources Wikipedia and others)

The Blue Mountains of New South Wales comprises a massive mountainous area covering 11,400 sq.kms. of sandstone plateaus and precipices some 50 kms to the west of Sydney, between the Nepean and Coxs Rivers. Gorges plunge straight down 760 m, while the highest point is the 1,215 m Mt Werong. A large portion of the Blue Mountains lie within the Greater Blue Mountains Area, a World Heritage Site because of its beauty, such as the Three Sisters, and the endangered species that live within its borders. Included in this area are seven national parks, including the Blue Mountain National Park visited during filming.

The Film Crew and Expedition Participants

From the UK:
David Wright (Director)
Robert Pendlebury (Associate Producer)
Mark O'Shea (Presenter)
Des Seal (Camera)
Matthew Seal (Camera assistant)
Terry Meadowcroft (Sound recordist)

In Australia:
Jonathan (Jonno) Webb (Northern Territory University, Darwin, NT)
Ros Whitten (Australian Reptile Park, Gosford, NSW)
John Weigel (Australian Reptile Park, Gosford, NSW)
Bradley (Australian Reptile Park, Gosford, NSW)
Arthur & Karen White (frog experts)
Martin Donahue (helicopter pilot)
Ashley Paton (Taronga Park Zoo, Sydney, NSW)
Nathan Cheeseman (spider expert)
Richard Wells (herpetologist)
Trevor Hawkesbury (herpetologist)


Special thanks to RobPendlebury and David Wright for the use of their images.
David's images are available commercially via his Flickr account

Mark with spider expert Roz Whitten
Mark with herpetologist Jonno Webb
The Funnel-web spider team:
(l-r) David Wright, Roz Whitten, Nathan Cheeseman, Mark O'Shea, Robert Pendlebury, Terry Meadwocroft, Matt Seal & Des Seal
photo: David Wright


The Expedition

Film 1, of Shoot 1, of OBA Season 2 centred upon two very different species, the endangered Broad-headed snake (Hoplocephalus bungaroides) of the Hawkesbury sandstone escarpments around Sydney and Nowra, and the Blue Mountain tree funnel-web spider (Hadronyche versuta) from the wet schlerophyll forests and rainforests of the Blue Mountains National Park. Our aim was to highlight the endangered status of the snake, vulnerable to collection or habitat loss, and to collect specimens of the spider for venom research.

When the crew and I arrived in Sydney, after our long flight, we were met by Director David and AP Robert who took us to Sydney's almost deserted Hyde Park for breakfast at an open-air café. Two cyclists were just leaving and as we ordered coffee and pastries from the waitress a woman arrived at the next table, sat down and opened her newspaper. When we had ordered she placed her order, and while we waited for our breakfast, David got down the business he wanted to discuss with us.

There was a problem with the third film of the shoot, in the Kimberley of Western Australia. Apparently YAP Films in Yorkshire, England, had received a report of an out-break of potentially fatal tick-borne encephalitis in the area and David wanted to make sure we all knew and to ask us if we were still happy to go ahead with the film. We were discussing the situation when a female voice said:

"Are you discussing my report?"

We looked over to see the woman at the next table had put down her newspaper and was leaning in our direction.

"I'm Vicki Krause, that is my report you are discussing"

It turned out Vicki, who I had not met before, was the wife of Bart Currie, a friend who specialised in snakebite, but both were based in Darwin, Northern Territory almost 4,000 kms to the northwest. She was the author of the report we were discussing, but the real coincidence was her presence in Hyde Park, the only other person, apart from the waitress, at the café early in the morning on that particular day. She had been at a conference and had stopped off in Sydney to visit their student son, who had been taken ill, and she was just taking breakfast in the Park to kill time while she waited to catch her flight back to Darwin.

Needless to say she was able to put our minds at rest about the tick problem, it was in a different part of the Kimberley to our planned destination so there was no need for us to change our plans, but what a strange coincidence.

And if you like coincidences, there was another one on the Season 4 film "Water Cobra" - click here to decide for yourself which is the stranger of the two.

A two-part narrative of the expedition is available for downloading:
On The Edge Part 1: Brace Yourself Sydney (4.4MB)
On The Edge Part 2: I Do Like Spiders and Snakes (1.1MB)
first published in The Herptile in 2010
note: the location of the Blue Mountains National Park is in error on the map in Part 1

The locations in New South Wales visited during filming of "On The Edge" were:

1. New South Wales
a) Sydney
b) Australian Reptile Park, Gosford
c) Waverley
d) Richmond
e) Blue Mountains National Park
f) Morton National Park, Nowra
g) Royal National Park

Filming schedule & itinerary:
Sunday 30th April - Arrive Sydney, NSW
Monday 1st May- Australian Reptile Park, Gosford, NSW
Tuesday 2nd May- Sydney & Waverley, NSW
Wednesday 3rd May - Australian Reptile Park, Gosford & Sydney Airport, NSW
Thursday 4th May - Taronga Park Zoo, Sydney, NSW
Friday 5th May- Richmond, NSW
Saturday 6th May - Sydney, NSW
Sunday 7th May - Sydney, NSW
Monday 8th May - Blue Mountains National Park, NSW
Tuesday 9th May - Blue Mountains National Park, NSW
Wednesday 10th May - Nowra, NSW
Thursday 11th May - Morton National Park, Nowra, NSW
Friday 12th May - Morton National Park, Nowra, NSW
Saturday 13th May - Morton National Park, Nowra, NSW
Sunday 14th May - Sydney, NSW (day off)
Monday 15th May - Taronga Park Zoo, Sydney, NSW
Tuesday 16th May - Royal National Park, NSW
Wednesday 17th May - Sydney, NSW
Thursday 18th May - Fly to Perth, WA


Expedition Results includes a full life-list for the "On The Edge" in New South Wales, Australia.


Quick links to other Australian films in the 2nd Season of "O'Shea's Big Adventure"
"The Pilbara Cobra"
"After The Flood"
"Sea Serpents"
"Feast of the Snakes"