- representative of the type of rabbit problems over a significant part of your district/region/geographic zone
- transect length: 2 km for each 100 hectares (minimum 10 square km for a district )
- transect traversable in all seasons
- transect can be completed in 4-5 hr or less
- transect route passes through main rabbit feeding areas
- transect adjoins warren monitor (active/non-active entrance counts) and/or warren/rabbit count sites
- historic transect data exists, to compare with new data What equipment and personnel are needed?
- 100w spotlight
- a vehicle suitable for observation (open tray 4WD, but not from the front seat, stand in the back with an appropriate safety harness!)
- a driver familiar with the terrain, who can also act as the recorder
- an observer to count rabbits, and operate the spotlight
How is a spotlight transect set up?
- select the transect route according to the selection criteria
- travel the transect in daylight to check you can do it in the dark
- break the transect up into 0.5 km segments
- mark the entire transect on a map
- peg/mark the transect at ground level
- set markers beside the transect route 50 metres either side of the transect
- GPS the transect in, marking the 0.5 km sections of the route if possible
When do you do a spotlight transect?
- every four months (minimum), monthly is better, more often in breeding seasons
- at anytime of the month (although best to avoid the bright conditions one week either side of a full moon)
- immediately after the last one, transects must be consecutive
- a variation of greater than 10% from a transect will require another transect to be done
- in stable environmental conditions, or at least on similar nights (but never in rain or drizzle)
How do you do a spotlight transect
- on the transect route count all rabbits and other relevant species
- count only within a predetermined distance (50 metres either side of the transect)
- record the number of rabbits (specifying ages as required and any other relevant species) every 0.5 km
- travel at the speed that allows the observer to count, 8-12 km/h
- always use the same vehicle
- always use the same observer to count
- travel the transect in the same direction
- only count. Do not shoot on the same evenings. Do not shoot even 2 days prior
Warren monitor site counts: Active/non-active entrances:
This method is simply counting how many burrows are active or non-active over the monitoring period. Warren monitoring overcomes some deficiencies of the spotlight transects and so provides valuable back up data to spotlight counts. Warren monitoring is an accurate way of gaining information on changes in the density of active and non-active burrow entrances per hectare.
What is an active entrance?
The term active entrance means that a rabbit is believed to have used that burrow when you checked it on the day of checking.
What is the relationship between active entrance and rabbits numbers?
The basic approximation for a warren system is that for each three active entrances there is one rabbit.
What else does a warren monitor site do for you?
This method also provides information on the number of warrens per hectare, which is in indicator of the potential rabbit carrying capacity of a site. What is a warren monitor site and how many do you need?
- an area of 1-5 hectares that contains about 30 warrens down to a minimum of 5 warrens
- each warren has a minimum of 3 burrows
- 7-10 warren monitor sites of 1-5 ha set along and/or beside the spotlight transect
Can a ripped warren be used?
- yes, these can provide evidence of rabbits recolonising sites
- ripped warrens also show the effect of your control methods (ie. D6 dozer vs Kato vs D9)
How is a warren monitor site set up?
- select a site that has an area of 1-5 hectares that is representative of the general topography and land management of the area, which has a minimum of 5 and up to +/- 30 warrens
- name the warren (eg. site 1 warren 1)
- record position & site details of the warren on a map of the area (1:25000) & on a data sheets
- mark the warren:- place a star picket in the middle of the warren
- write on a cattle tag (or similar) the warren/site details and secure it to the star picket
- measure the warren size (pace to the outer edge of the warren in 4 segments divided into north / south / east / west eg. north 10 paces, south 8, east 7 , west 2)
- count the number of rabbit burrows that are being used (active entrances) and the number not being used at this moment (non-active entrances)
- record the number of active and non active entrances which you have counted
- GPS: use a geographic positioning system to accurately record data collected if possible
- review, analyse and discuss data
Warren/rabbit counts:
The technique involves counting of rabbits that have emerged from warrens. Provided that counts are done in a consistent manner under similar weather conditions, you can expect less variation than with spotlight transect counts.
This method gives better appreciation of the age of rabbits on each warren (small kittens, subadults, and adults) and the occurrence of localised disease outbreaks (RCD or myxomatosis). Observation must be made of a number of warrens in the same land type as well as observations across the variety of land types and land classes in the rabbit infested areas to get an idea of rabbit numbers. Disease outbreaks and the start of breeding season can be picked up with this method.
Farmers, Landcare groups, conservation groups:
Farmers, landcare groups, conservation-based groups, and other interested people are encouraged to conduct these counts on their land. The information gained can help produce a regional/catchment assessment of rabbit numbers.
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