Why Map Warrens at All?
If you are planning rabbit control, the first job is knowing exactly where the warrens are. Our main guide on rabbit control focuses on lasting control through dealing with warrens. This article covers the step before that: finding warrens, recording them and monitoring rabbit activity so you can make informed decisions.
According to NSW DPI guidance, mapping the distribution of rabbit damage and density across a property helps with both developing and assessing rabbit management plans. It gives you a picture of where rabbits are active, where the pressure is highest and where follow-up monitoring should occur.
The national standard operating procedure for warren ripping starts with mapping all warrens, including active and inactive sites and those that are easy or difficult to access. The Glovebox Guide for Managing Rabbits also identifies mapping warrens before ripping as an important precaution.
A simple example shows why it matters. Imagine obvious creek-line warrens are identified and treated, while hidden warrens under blackberry are missed. Those overlooked sites can continue supplying rabbits into the same paddocks. A property map helps avoid spending time and money on only part of the problem.
Finding Warrens
What to look for
South Australian government advice lists several common signs of rabbit activity. Burrows are the most obvious, but fresh scratches in the soil, scattered or piled dung and damage to vegetation are also useful indicators.
Rabbit Free Australia also highlights small trench-like diggings and dung heaps as signs worth noting. NSW DPI guidance notes that rabbits can create grazing lines on shrubs up to about 40 cm high.
Heavy grazing pressure often points you towards a nearby warren. South Australian government advice states that rabbits generally do not travel more than 200 metres from home and usually feed within 25 to 50 metres. If one corner of a paddock is being worked over, the source is often close by.
The hidden ones
Not every warren sits out in the open. NSW DPI guidance lists harbour such as warrens, blackberries, fallen logs and native vegetation. South Australian government advice also notes that rabbits shelter under thick vegetation and materials such as wood piles.
These areas deserve a slow and careful inspection. Blackberries, timber piles, fallen logs and rocky country can conceal entrances that are easy to miss during a quick drive around the property.
The national standard operating procedure for warren ripping notes that surface harbour, including blackberry stands, hollow logs and rock piles, may need attention before warren destruction can occur effectively.
Rabbit Free Australia notes that warren smoker kits can help identify exits in dense vegetation and that detector dogs have been used to locate difficult warrens. For larger properties, PestSmart describes a process where an experienced observer maps warren locations with GPS and visibly marks each site while moving through the area.
Useful resources:
- Rabbit Free Australia assessment resources
- PestSmart overview of rabbit warren and harbour destruction
When to look
A 2021 New South Wales study by Cox, Matthews, Halverson and Morris found that vegetation was a significant factor in detecting warren entrances. Active warrens were detected when vegetation was scarce.
That suggests the easiest time to find entrances is often when cover is thinner and visibility across the ground is better. This is an inference from the study findings rather than a formal government recommendation.
It also aligns with South Australian government advice that late summer and autumn are generally the best times for rabbit control because food sources are lower, rabbits are not breeding and dry soils are easier to work. Finding warrens, mapping them and planning control can fit neatly into that same period.
Recording What You Find
Once you locate warrens, record enough information to compare future inspections against today’s conditions.
- Warren locations, ideally with GPS points.
- Size of each warren.
- Ratio of active holes to total holes, such as 9/14.
- Harbour including blackberry and fallen logs.
- Rabbit feeding locations.
- Topographic features including watercourses, hill contours and rock outcrops.
- Property boundaries, permanent fences, gates and roads.
NSW DPI guidance also recommends physically marking warrens in the field. A tagged star picket placed in the middle of a warren helps identify the site later. Record the location on the map and GPS where possible, and note the size of the warren using a consistent field measurement. Paper maps work well, but digital records work just as well. PestSmart’s RabbitScan mapping and planning tool can record warrens, rabbit impacts and control activities. The NSW Government also directs landholders to FeralScan rabbit control resources.
Counting Rabbits: Spotlight Counts and Active Entrances
Spotlight counts
NSW DPI guidance describes spotlight counts as a way of producing an index of rabbits per kilometre along a fixed route.
- Use the same fixed transect for every survey so comparisons remain valid.
- A transect between 2 and 10 km is considered ideal.
- Travel at a constant slow speed, with 15 km/h commonly used.
- Scan a 90 degree arc ahead and count rabbits within 50 metres on either side.
- Start at least half an hour after sunset and avoid high wind or heavy rain.
- Use the same observer or observers wherever possible.
Repeat counts across three or four consecutive nights. Average the results and divide by the transect length to calculate rabbits per kilometre.
For routine monitoring, NSW DPI guidance recommends conducting counts at least quarterly so seasonal changes can be observed. To measure the effect of a control programme, perform counts immediately before the work and again about one week afterwards.
Active entrance counts
NSW DPI guidance describes active entrances as having a smooth floor, recent soil disturbance, foot or claw impressions, fresh urine or pellets and hair. Inactive entrances often contain leaves, grass heads or weeds across the floor, wind-blown or rain-washed soil, old pellet layers or spider webs.
The same guidance notes that during the non-breeding season there is approximately one adult or sub-adult rabbit for every 1.6 active entrances.
Using the Map to Plan Control
South Australian government advice recommends preparing a control plan in advance so the right methods can be used at the right time and in the right sequence.
The sources are consistent about the general sequence of work. Baiting is undertaken first, followed by harbour and warren destruction, with fumigation used as follow-up where required. The national standard operating procedure for warren ripping notes that ripping is most effective when rabbit numbers have already been reduced, such as after a baiting programme, drought or disease outbreak.
A good map helps identify the most active warrens, the places machinery can access and locations where other techniques may be better suited because of fences, timber, rock or other constraints. It also highlights where rabbit activity approaches a boundary.
Rabbits do not respect property boundaries. South Australian government advice notes they can quickly move back into treated areas. Coordinated action with neighbours at a similar time can therefore improve planning outcomes. Local Land Services can coordinate group rabbit control programmes involving five or more adjoining properties. Landholders can learn more through LLS support information for NSW landholders.
Technology is also expanding the available options. The 2021 New South Wales study found professional thermal imagers detected more warrens and entrances than consumer imagers or visual inspection. Rabbit Free Australia notes that drones are another option in rough or inaccessible terrain, although thermal imaging has not yet been widely used for rabbit warren mapping. Learn more about thermal drone surveys.
Checking After Control
Monitoring does not stop once control work is complete.
- 2 to 3 days after ripping: Check for re-opened entrances. The national standard operating procedure for warren ripping states that widespread re-openings may indicate further ripping is required, while a small number of re-openings may be suited to fumigation.
- About one week after fumigating: Inspect treated warrens for re-opened entrances and undertake further treatment where required according to PestSmart guidance.
- Monthly after that: South Australian government advice recommends monthly inspections and treatment of any re-opened holes.
- Each assessment: NSW DPI guidance recommends producing a new map each time and comparing it with previous records.
Consistent monitoring gives you evidence of change over time. It also helps identify missed warrens, new activity and areas where follow-up work deserves priority.
When are you on top of it?
There is no official threshold that defines success. A practical approach is to keep monitoring and compare the results from one period to the next.
You are generally looking for spotlight counts per kilometre that fall and remain low, re-opened entrances that become uncommon and are dealt with quickly, and an absence of fresh digging activity in previously treated country.
The Glovebox Guide stresses that regular monitoring is crucial to prevent rabbit populations building up again. NSW DPI guidance also notes that in low-productivity areas, densities as low as one rabbit per hectare can prevent native plant regeneration.
If you want your warrens mapped and a practical control plan built around your country, get in touch about rabbit control or learn more about our rabbit control services. Call 0493 417 929.