War against the rabbit (1954)

[Birds warbling and text appears: War against the Rabbit. Produced for The Vermin and Noxious Weeds Branch, Department of Lands and Survey Victoria by C.S.I.R.O. Film Unit. Direction & Photography – R.R. Crispe; Art Work – L.H. Kelly; Supervision – S.T. Evans]

[Image changes to show a rabbit nestled in the undergrowth]

[Image changes to show a rabbit running through an open paddock]

Narrator: The rabbit is one of Australia’s serious rural problems. It has been a curse in every district, wherever is has secured a foothold. It has defied the most strenuous efforts of control and destruction, always because enough have survived to provide a nucleus for a fresh outbreak when good seasons returned, or when the control measures were relaxed.

[Image changes to show Heck Bradley walking through a paddock with a dog]

Heck Bradley realised this grim and unpleasant fact when he noticed that the rabbit population was building up on his property.

[Image changes to show rabbits running through a paddock]

He was a farmer who carried along the endless toil of rabbit eradication year after year, killing hundreds on his property, but never planning a serious effort to stamp out the pest once and for all.

[Image changes to show Heck Bradley walking through a paddock]

He saw clearly now, as he walked around his property, that his fences and gates were not as well maintained as they could have been, that the rabbits had increased in number.

[Image changes to show a dog chasing a rabbit]

[Image changes to show Heck Bradley walking through a gate on his property]

The fact was he had relied too much on myxomatosis to wipe out all the rabbits on his and his neighbours’ properties. Clearly it was high time to intensify his activities to rid the property of this pest before all the pasture was completely ruined.

[Image changes to show Heck Bradley getting into a motor vehicle]

[Image changes to show Heck Bradley speaking to a group of men]

Heck Bradley was not the first farmer in the district to see the danger of another rabbin infestation, and to seek the advice of the local Lands Department inspector. Two farmers from his own neighbourhood were already there preparing to move out to clean up an area from whence rabbits repeatedly spread out to reinfest their lands. They were taking along some equipment they had hired from the Lands Department, and the inspector was going to help them plan the campaign. They agreed that Bradley should look over this area and follow the eradication program as it was put into practice.

[Image changes to show an open paddock]

This was the heavily infested area as Heck Bradley first saw it. It was a 250 acre paddock owned by one of the other farmers, a rabbit breeding ground not far from his own property. A survey of the paddock revealed that rabbits had bred up to a population of between five and 6,000. Here the pest was firmly entrenched in rocky outcrops along the crest of the hill. In this area all the better grasses had been eaten out and noxious weeds such as nettles, thistles and inkweed were now growing.

[Image changes to show various noxious weeds]

There were warrens on the hill slopes and under top cover, such as dense tussock grass.

[Image changes to show various rabbit warrens]

Excessive grazing by the rabbits depleted surface cover. Water runoff increased, it sluiced down through burrows on the hillside, producing tunnel erosion, later developing into gullying.

[Image changes to show evidence of tunnel erosion and gullying]

[Image changes to show various rabbit warrens]

Warrens scarred the open country and around trees and stumps. There were shelters in logs, and warrens extended undercover of box thorns.

[Image changes to show a rabbit leaving a log and entering a warren under a box thorn bush]

[Image changes to show various images of erosion in a paddock]

Rabbit grazing had been followed by heat(?) erosion, too. Instead of pasture, much of the area was bare ground. Cake weed had spread extensively on the hilly slopes; all the grasses and clover had been eaten out.

[Image changes to show remaining weeds in a section of ground]

The only plants to survive close cropping by the rabbits were weeds of poor grazing quality. The land was barely able to carry one sheep to five acres.

[Image changes to show Heck Bradley speaking with a neighbouring farmer and the Lands Department inspector]

The eradication plan outlined by the district inspector for cleaning up the paddock was of special interest to Heck Bradley. In another few weeks he would have to tackle the job himself on his own property.

[Image changes to show a picture of the property]

A close look at an actual layout of the property showed difficult rocky outcrops along the top of the hill, warrens on the open country plateau and along the hillside, and warrens on the flat area below the hill. The campaign started with the inspector proposing a thorough check over the property to ensure that all fences and gates were effectively netted.

[Image changes to show the district inspector speaking to the farmers]

He emphasised that this is the only way to exclude rabbits completely and protect the property.

[Image changes to show a picture of the property]

The next step is poisoning. Trails of freshly turned earth will be run between feeding grounds and warrens and around patches of cover so that free feeds can be laid before the actual poisoning.

[Image changes to show the trail on the picture of the property]

Poisoning, when properly carried out, is a quick and effective method of destruction. It reduces the infestation so that other work, such as fumigation and ripping, may be carried out with greater success.

[Image changes to show the district inspector observing the paddock with the farmer]

After all fences and gates have been checked the plan is got underway, first by reconnoitring the area to be poisoned in order to make an estimate of the length of trail and the quantity of fruit or other material needed for bait. Care should be taken to avoid disturbing the rabbits before and during poisoning, therefore all dogging operations, shooting and trapping must be suspended.

[Image changes to show a notice indicating rabbit extirpation to occur]

Of course stock must be removed from the area and poison notices placed at strategic points over the property, and on adjoining properties when co-operative poisoning is planned.

[Image changes to show farmers ploughing a furrow]

As rabbits are attracted to newly turned earth the furrow should run between the rabbit harbour and the feeding grounds so the rabbits will come across the trail when they move out to feed in the evening. This implement has been improvised to suit the hilly nature of the country. In fact any implement can be used which will cut an even, open furrow so that baits may be easily seen by the rabbits.

[Image changes to show the farmer indicating toward the furrow]

[Image changes to show the farmer driving a tractor through the paddock to create the furrow]

Laying the trail in the right places ensures that the greatest number of rabbits will feed on it. On hill slopes it is important to remember that trails must be made as close as possible to the contour to minimise erosion hazards. Furrows are cut around warrens, across rabbit pads and runs, through feeding grounds, and between harbour and feeding grounds.

[Image changes to show the farmer indicating to various places furrows are made]

The difficulty of making a trail through rough areas and on steep grades inaccessible to a tractor is readily overcome by using this ring and setter.

[Image changes to show a ring and setter]

It can be drawn by one member of the team.

[Image changes to show the farmer dragging the ring and setter along the ground behind him]

A rather different problem exists in the rocky stretch at the top end of the paddock. This is a rabbit stronghold, and must not be overlooked.

[Image changes to show the farmer turning over the soil between the rocks]

Here a handsetter is used to turn over patches of soil in between the rocks.

[Image changes to show the farmer and a Lands Department officer preparing feed with a bait cutter]

There is no time of the year, wet or dry, when rabbits cannot be induced to take some form of bait. They will always take apples or carrots, provided care is taken in the preparation, and provided the material used for the bait is good quality.

Several types of bait cutters are available. Here an inspector demonstrates a simple mechanical type.

[Image changes to show an inspector turning the handle of a bait cutter]

The accepted practice when using apples or carrots is to free feed the rabbits for at least three nights. This gets them accustomed to coming to the trail to feed.

[Image changes to show the farmer dropping feed into the furrow]

The quantity of bait required for the first night is based on the nature of the rabbit infestation. The inspector has reckoned the first application of one kerosene tin to the mile. This is done in the afternoon so that baits will remain fresh and tempting. The rate of application on the second and third nights is determined by the amount left on the trail after the previous feed. If for instance all the free feed has been eaten on the first night the amount should be doubled on the second night. Where there are still some left on the trail the amount need not be increased. On the third night increase the quantity of feed in those parts where it was all eaten out on the other nights.

[Image changes to show a farmer making a furrow and dropping feed into it at the same time]

Another farmer in the district is using a vehicle equipped with a trail maker. The free feed, oats in this case, can be fed at the same time. 1080 is the poison in general use for rabbit control, although strychnine is still used in certain circumstances.

[Image changes to show a farmer and a Lands Department officer preparing feed with a bait cutter]

The bait is prepared in the same way as for free feeding.

[Image changes to show a Lands Department officer preparing the poison]

Health regulations which govern the use of 1080 poison stipulate that rubber gloves must be worn when handling the material. One fluid ounce of 1080 is sufficient to treat a kerosene tin of bait. The 1080 is mixed with water and is then ready for use.

[Image changes to show a farmer digging out the soil and then preparing the bait with the Lands Department officer]

Special precautions are necessary for mixing the poison with the bait. An area of soil must be dug out and the mixing carried out on this area. A very small charge is made by the Department for the supply of 1080 to landholders. In all cases the Lands Department officer, who is authorised under the Health Regulations, is the only person to actually handle the poison. Thorough mixing of the bait is essential if good results are to be obtained.

[Image changes to show the Lands Department officer mixing the bait with the feed]

After mixing the container must be carefully washed out on the prepared site.

[Image changes to show the Lands Department officer cleaning out the container]

Finally the soil must be replaced to avoid any risk to farm animals and wildlife.

[Image changes to show the farmer replacing the soil over the site]

Rubber gloves must again be worn when laying the poisoned bait on the trail.

[Image changes to show the farmer putting on rubber gloves and then laying the poisoned bait on the trail]

Remember to spread the baits more plentifully in those sections of the trail where the free feeds were taken most readily.

[Image changes to show a farmer nailing a notice on a gate post]

Notices should be displayed in prominent positions.

[Image changes to show farmers collecting dead rabbits]

This simple technique of poisoning can be carried out at any time of the year, irrespective of the season and of the available food supply, but there is a special advantage in poisoning during the breeding season, because then the unborn rabbits will be killed as well. Each doe can produce several litters each year, and doe’s can begin to breed when they are 16 weeks old. This means that a mere hundred breeding doe’s killed in the winter and spring is as good as killing thousands of rabbits in the summer months. There are two points to be observed after using 1080. All baits that remain should be destroyed, and all dead rabbits collected and then burned or buried.

[Image changes to show rabbits being buried]

[Image changes to show farmers walking through a paddock with their dogs]

However successful the poisoning, there are always some rabbits left to breed again, so poisoning should be followed by fumigation. But before fumigation is carried out it is essential to eliminate all top cover which may provide surface shelter for rabbits.

[Image changes to show dogs chasing rabbits in a paddock]

If this is not done before fumigation begins loose rabbits are left on the surface to open up sealed burrows. Therefore the area to be fumigated should be worked thoroughly with a dog pack to kill surface rabbits or drive them underground. Heck Bradley’s dog joined in the work of chasing down loose rabbits when Heck came over to the paddock to follow the progress of the work.

[Image changes to show a box thorn bush being pulled out of the ground, and thistles being chopped out of the ground, and logs being removed]

He arrived in time to see box thorns pulled out to reveal warrens extending under their roots, thistles hiding burrows and shelters in hollow logs, dead trees and stumps concealing entrances to warrens.

[Image changes to show fires being lit in a paddock]

Low scrub and tussocks were removed by firing, which was permissible at this time of the year. Now with all surface cover removed and the area thoroughly dogged, the inspector outlines his plan for treating the area with fumigants.

[Image changes to show a picture of the paddock plan for fumigation]

Having equipment readily available he was able to demonstrate three methods of fumigation. The rocky areas will be treated with chloropicrin, flame fumigation is to be for the warrens on top of the rise and on the hill slopes, calcium cyanide dust and the blower unit will be used on the flats. When fumigation has advanced on a wide front past the worst rocky area, this area will then be netted off, sprayed with arsenic pentoxide to kill all plant growth, and the rabbits left to starve.

[Image changes to show a farmer fumigating an area of rocky outcrop]

In other rocky areas the fight is all on the side of rabbit, as it shelters in a multitude of short burrows, in hollows under tree stumps, and in rocky crevices. Chloropicrin is useful in such places. It can be easily squirted into burrows and crevices, and is very toxic to rabbits. In most situations chloropicrin can be used with complete safety, but in certain places, such as among rocks or on steep creek banks, it is advisable to wear an ordinary gas mask.

[Image changes to show a farmer putting on a gas mask]

Complete blocking of an opening is essential, as in all methods of fumigation.

[Image changes to show a farmer blocking an opening with rocks and dirt]

Chloropicrin can be used effectively in almost any area, and is particularly useful for checking over treated warrens to deal with any fresh opening.

[Image changes to show a paddock]

The fumigation campaign now moves to the open county, working on a wide front away from the rocky area. Here the warrens are mostly covered with nettles and thistles. No opening is to be left untreated, and the whole area is flagged in advance of the fumigation unit.

[Image changes to show farmers working in a paddock]

The direction of the wind determines which side of the warren to work from. The main opening is selected on the outer perimeter, where the team can work with its back to the wind. The opening is first dug back to a solid face, and the fumigator is placed in position.

[Image changes to show a farmer digging the soil, and then placing the fumigator in position]

The killing agent is phosgene gas, which is generated when drops of carbon tetrachloride decompose in the heat of the flame. As smoke emerges from connected openings they are broken down and filled in.

[Image changes to show a farmer filling in the hole]

Usually a thin crust of surface earth extends over the entrance to a burrow. If this is not dug back to solid ground the crust may be broken and rabbits will escape. Also, it makes it easy for loose rabbits to reopen the warren. Another important aspect of digging back is to determine whether there is another run with the one being treated. The connected opening from which smoke emerges must be properly sealed.

[Image changes to show the farmer sealing the opening]

The other opening is then dug back ready for treatment.

[Image changes to show a farmer digging the soil, and then placing the fumigator in position]

When this method is adopted every burrow is certain to receive the maximum concentration of gas. Work is completed only when every opening has been sealed and when the entire surface has been levelled off. The portable blower unit employing calcium cyanide dust can also be used successfully. Here again it is necessary to choose an opening on the windward side of the warren.

[Image changes to show farmers using the portable blower unit]

This fumigant has the advantage that it continues to produce deadly gas up to 24 hours after the dust has been blown in. The procedure for digging back and filling in is the same, no matter what fumigant is used.

[Image changes to show a farmer digging the soil, and then filling in the hole]

It is essential to inspect the warrens the next day. Fresh openings can be treated with ounce of flake calcium cyanide deposited well down the burrow, which is again sealed and levelled off.

[Image changes to show a farmer placing calcium cyanide into the hole, and then digging the soil and filling in the hole]

[Image changes to show a tractor ripping in a paddock]

Ripping follows fumigation. This is necessary to destroy the structure of the warrens.

[Image changes to show a computerised image of a warren system]

As the inspector explained, fumigation is carried out before ripping because warrens are often constructed in two or even three layers. Ripping will destroy the upper two or three feet of warren structure, but unless the warren is fumigated before ripping rabbits sheltering in the lower layers will be unharmed and will reopen the warren.

[Image changes to show a computerised image of runouts contained in the warren]

In ripping it is good to remember that there are usually runouts from the main burrow which end just below the surface. Consequently the ripping should start about ten feet outside the surface perimeter of the warren.

[Image changes to show a computerised image of a ripping pattern]

First rip and down the slope using a single or double tined implement. At each end the ripper is lifted out before turning for the next run. Each rip should be about 18 inches apart, working progressively across the warren until the overlap of ten feet is reached on the other side. The warren is then cross-ripped, adopting the same procedure, but keeping as close as possible to the contour.

[Image changes to show a computerised image of a tunnel ripping pattern]

Tunnelling is treated in much the same way, rip up and down the slope first to break in the tunnel structure, and then cross-rip along the contour, but in this case only two rips to the chain are made across the tunnel. Soil conservation authorities will give advice on problems of tunnelling and gullying.

[Image changes to show Heck Bradley, a neighbouring farmer, and a Lands Department officer observing a paddock]

Heck Bradley was convinced that rabbit eradication pays, and pays handsomely, when it has been diligently carried out. This is how his neighbour’s paddock looked only three months after rabbits had been completely eliminated. In the absence of rabbits the natural grasses had regenerated and were flourishing. There was now a good cover of wallaby grass, kangaroo grass, and some clover.

[Image changes to show a close up camera shot of the regenerated grasses]

[Image changes to show sheep running into a paddock]

This land which has barely carried one sheep to five acres under rabbits was now capable of carrying one to one and a half sheep to the acre without further pasture improvement.

[Image changes to show sheep grazing in a paddock]

The cost of an eradication campaign such as this in a heavily infested area is fully repaid by increased returns in one year.

[Image changes to show Heck Bradley inspecting fences on his property]

And so Heck Bradley set to work in a campaign of simultaneous action with a group of neighbours to rid his area of rabbits. It began first with a thorough check over all fences and gates to see that they were properly netted.

[Image changes to show a fencer repairing netting on a fence line]

New netting was erected where necessary.

[Image changes to show a farmer dropping feed into the furrow]

Then poisoning to reduce the heavy infestation, so that the work to follow might be carried out more effectively. Clearing to remove all top cover which harboured and protected rabbits.

[Image changes to show top cover being cleared]

[Image changes to show dogs chasing rabbits]

Dogging to kill surface rabbits, or drive them underground.

[Image changes to show a farmer treating warrens and openings with fumigants]

Fumigating and sealing all warrens and openings.

[Image changes to show ripping being carried out in a paddock]

Ripping to destroy the structure of the warrens. And finally harrowing the ripped warrens and sowing them down to pasture.

[Image changes to show a farmer driving a tractor over the ripped warrens]

[Image changes to show Heck Bradley and another man walking through a paddock]

Once the rabbits have been eradicated the land must be kept free of the pest by giving proper attention to fences and gates, combined with regular patrols of the properties and a will to wage war on rabbits when and wherever they reappear.

[Image changes to show a man on horseback and sheep grazing in a paddock]

[Text appears: Attack the Rabbit now! Sound of a tractor engine starting and a dog barks]