European rabbits

Identify rabbits and their impacts

Large populations of rabbits are relatively easy to detect as the damage they cause is usually widespread and highly visible. However the damage caused by low density rabbit populations can  be much harder to identify – and may be more serious (eg  preventing regeneration of an endanagered plant species). Rabbit numbers, and changes in their impact, can vary dramatically in a  short period of time. Without ongoing monitoring and control, these changes can go unnoticed and the problem can get out of hand, resulting in higher management costs.

Monitoring rabbits

Rabbit density is a practical indicator of a potential rabbit problem  and can be measured easily, quickly and cheaply. Rabbit density can  be estimated directly by counting rabbits or indirectly by counting  warrens, active warren entrances or signs of rabbits (eg tracks, dung).  Instructions on how to rapidly assess a rabbit problem using a simple, visual-based technique can be found in the booklet  Rabbits: a threat to conservation and natural resource management. Detailed  descriptions of other monitoring methods can be found in the books Monitoring techniques for vertebrate pests: rabbits and Managing vertebrate pests: rabbits.

Is it a rabbit, hare or bilby?

In some situations, it may be difficult to identify what animal you are  dealing with, particularly if you are using indirect monitoring methods. There are animals of similar size  and appearance to rabbits, such as hares and bilbies. Hares are an  introduced species from the same genetic family as rabbits  (Leporidae). They live in similar habitat types but are usually solitary,  and do not build large warrens like rabbits. Greater bilbies  are small, protected native animals that have similar sized tracks to  rabbits, and also live in warrens.

Other key differences between the three species are:

• hares are noticeably larger than rabbits, with a head and body  length of 55 cm while rabbits are about 40 cm in length
• a hare can weigh twice as much as a rabbit
• a hares hind legs are relatively larger than a rabbit’s
• hares can run faster than rabbits
• hares have relatively longer ears than rabbits, with distinct black  tips
• rabbit warrens often have more entrances than bilby burrows,  and entrances are usually larger
• rabbit diggings are generally shallower than bilby diggings, and  tend to be long and narrow.

European rabbit. Image by Neil Schultz

European brown hare

Greater bilby. Image by SEWPaC

Measuring damage and costs

Simple damage assessments can also be used to identify a serious  rabbit problem. These include visual assessment of crops eaten out  50 m from warrens, distinct ‘browse-lines’ 500 mm above the  ground on shrubs and foliage within reach of the rabbits, increased  presence and spread of invasive weeds, and scratching and soil  disturbance. Quantifying rabbit impacts using other measures can  be difficult, costly and time-consuming, and are generally not  practical for many land managers. When assessing suspected rabbit  damage to vegetation, crops or pastures, it is important to  remember that other animals such as grasshoppers, hares and  wallabies might cause similar damage.