History of the rabbit in New Zealand
The European Rabbit (Oryctolagus cuniculus) was originally from Spain and Portugal and were brought to New Zealand and introduced at multiple sites through New Zealand from 1830s onwards for meat and sport. There have been known accounts of Rabbits released inland from Blenheim in 1858 and 1865. As early as 1870 they were spreading up the Wairau and Awatere Valleys. There have been ‘plague’ episodes since the late 1890’s which have come and gone and continue to do so in areas of New Zealand. Once rabbits invaded dryland pastoral farms it caused major problems for farmers; at a station in Lake Wakatipu carrying capacity went from 20,000 sheep to just 2,000 sheep, lambing percentages fell from 70% to 45% and farmers were walking off the land.
Manual traditional means of controlling rabbits (such as shooting, dogging and trapping) were unable to cope with the high numbers and various poisoning efforts ensued and rabbit proof fences were installed. Big rabbit issues still remained despite huge amount of money and effort put into rabbit control. Further population outbreaks in 1980s brought frustrations to farmers again and by mid-1996 after a decline of the application to bring RHD virus into the country, farmers illegally introduced it. Initially the RHD virus was very effective, however by 2007 signs of immunity to the RHD virus was evident and poisoning had to resume again. (Information sourced from Te Ara - The Encyclopaedia of New Zealand).
Why is the rabbit a pest?
Rabbits thrive in dry and semi-arid environments. Rabbits have high reproductive systems; females can be pregnant for 70% of the year and can adjust their litter size according to food supply. Female rabbits can produce a litter within the same year that it’s born in. When high numbers of rabbits occur they are able to reduce pastoral drylands to nothing but dirt and stone, dramatically reducing stocking capability and increasing erosion.
Marlborough has several rabbit-prone areas predominantly in South Marlborough; Coastal Ward, Upper Awatere, and Wairau Valley have had high numbers of rabbits in the past and still have the potential to have serious issues.
For this reason, they are a declared pest within the Council’s Regional Pest Management Strategy (RPMS). Landowners in rabbit prone areas are obligated to control rabbits to a certain level.
For this reason, there is a programme for feral rabbits within the Regional Pest Management Plan 2018 (RPMP). All land occupiers areas are obligated to maintain rabbit populations to at or below a threshold. In the more rabbit prone areas of the Upper Awatere Valley and into the Clarence catchment, this threshold is slightly higher due to the feasibility of under taking regular control if necessary. See Regional Pest Management Plan 2018
What are satisfactory levels of rabbits and how are they assessed?
Councils that have rabbit issues through New Zealand follow an assessment called a Modified McLean Scale (MMS). The MMS has levels (levels 1-8); level 1 being nothing seen, through to level 8 which is extensive and extreme high number of rabbits. MMS assesses not just the actual rabbits seen but more the visible signs of the rabbit presence; fresh diggings, heaped up faecal pellets (called buck heaps), active burrows, etc. The more fresh sign observed, the higher the rabbit population.
In Marlborough, we have two MMS levels depending on area. In the Upper Awatere the maximum acceptable level is MMS level 4, everywhere else in Marlborough the maximum acceptable level is MMS level 3. Below is a basic table showing what levels are acceptable and not acceptable and a description of what that looks like on the ground.
|Description||Compliant/Non-compliant under MDC pest strategy|
|No sign found, no rabbits seen||Compliant|
|Very infrequent sign present, unlikely to see rabbits.||Compliant|
|Pellets heaps spaced 10m or more apart on average, odd rabbit seen.||Compliant|
|Pellet heaps spaced 5-10m apart in average, pockets of rabbits, sign and fresh diggings/burrows noticeable.||Non-compliant for all of Marlborough (except Upper Awatere Valley)|
|Pellet heaps spaced 5m or less apart on average, fresh sign and burrows noticeable, infestations spreading out.||Non-compliant for all of Marlborough (including Upper Awatere Valley)|
|Sign very frequent with pellet heaps often less than 5m apart, a lot of rabbits seen.||Non-compliant|
|Frequent sign with 2-3 pellet heaps often less than 5m apart over the whole area, large number of rabbits seen.||Non-compliant|
|Very frequent sign with 3 or more pellet heaps often less than 5m apart over the whole area, rabbits seen in large numbers over the whole area.||Non-compliant|
How can rabbits be controlled?
There are several ways rabbits can be controlled:
- In areas where there are small-moderate populations shooting is effective. Walking with a supressed rifle is the most ideal as rabbits can become spooked easily and learn quickly to disappear upon hearing vehicles and/or gunfire.
- Poisoning is very effective on large populations and/or over large areas. Pindone or 1080 are two registered toxins used for rabbit control.
- Fumigation is also a technique used, more for smaller properties where active burrows can be found. The toxin used for fumigation is Magtoxin and it is put down the holes of active burrows and all entrances and exits are sealed to ensure no toxic gas is leaked out and rabbits cannot escape.
- In small areas such as lifestyle blocks or around specific trees/shrubs, rabbit proof fences can be erected to stop rabbits from entering.
- To stop specific trees and shrubs getting eaten a rabbit repellent can be used which can be effective but may need to be re-applied regularly.
What does the Council do?
Council inspect certain rabbit-prone properties annually (dependent on expected rabbit numbers for the season) to ensure that rabbits are not exceeding the appropriate MMS levels for that area. The inspections are generally conducted in Autumn after the natural peak of rabbits in spring. Autumn rabbit population give an indication of the population size going into winter and likely to be producing litters in the next spring.
Council conducts set rabbit nightcount routes every year to provide information on rabbit population trends over time. Some of these nightcount routes have been monitored since 1986 so we have good information of the rabbit populations in these areas.
Council annually shoots a sample of rabbits to send off for RHD virus immunity testing to collect information on current RHD virus immunity levels in the Marlborough Region.
MDC also participates in a national partnership run by MPI (Rabbit Coordination Group) which gathers together councils and other interested stakeholders to keep up to date on what other regions are doing, and provide support where possible for current research on rabbit management.
Council produces a newsletter to keep landholders (primarily in the rabbit-prone areas) informed of rabbit issues in Marlborough and information from the Rabbit Coordination Group meetings.
Feral rabbit newsletter
The newsletter contains the latest information relating to rabbit control, current population trends (April 2011 issue), results of RHD immunity testing (August 2011 issue) and general information to assist landholders in the battle against the resurgent rabbit.