Problem Wildlife
Welcome to the Problem Wildlife pages of the Department of Primary Industries (DPI)/Department of Sustainability and Environment (DSE) Internet site. These pages aim to assist in solving problems and/or damage that native wildlife may cause.
Problem Wildlife Notes - (Department of Primary Industries)
The information to be made available through these pages is provided in good faith. Since the behaviour of many animals is difficult to predict, results are not guaranteed, and the Department of Primary Industries/Department of Sustainability and Environment may not be held liable for any claims arising as a result of use of the information on this site.
For the purpose of these pages, wildlife means all birds, mammals, reptiles and amphibians native to Victoria, as well as two introduced species of deer. All native wildlife is protected under the Wildlife Act 1975.
Research into problem wildlife such as kangaroos and deer is undertaken at the Arthur Rylah Institute for Environmental Research.
Assessment of the Problem or damage
Some wildlife can cause significant damage to crops or property, or create a serious risk to public health or safety. For example, the large number of Silver Gulls at some airports can be a hazard to air safety; large numbers of Welcome Swallows roosting in warehouses may present a hazard to workers' health and damage stored goods; cockatoos attacking houses or cereal crops may cause significant economic loss; wallabies browsing newly-established plantations may necessitate replanting.
Sometimes, a problem may seem to be larger than it really is. In such cases, discussion of the problem with another person, and an objective assessment of the facts, may help to put the problem in its proper perspective. Management of the problem often incurs a cost, whether it be in materials, time, altered practices, or some combination of these. This cost should be weighed against the level of damage being caused. On this basis, you can assess whether it is worth your while attempting to solve the problem.
Problems may be more of a nuisance than an economic consideration. Nevertheless, it is still important to assess carefully the real nature and extent of a problem, before deciding on the need for action.
You need to learn which kinds of birds are likely to cause problems. Many bird species which forage within a crop are insect-eaters, and are likely to be beneficial. Their impact on insect populations (including some pest species of insects) can be significant. You should appreciate their presence and encourage them.
Bird identification books are listed in the Further Reading section of these notes. Guides to the identification of mammals, reptiles and amphibians are also listed. If you do not know the name of a species which is causing problems, then you will find these guides helpful. They should be available in most libraries and in larger bookstores.
Combining of Methods
Where strategies are suggested to reduce a problem caused by wildlife, their results will usually be more satisfactory if a combination of measures is applied simultaneously. This is particularly the case with bird scaring. You need to be more persistent in the use of scaring techniques than the birds are in attempting to return. Initially, this may involve long hours and hard work.
In the case of birds being attracted by food, they are usually less difficult to deter if you can employ scaring techniques before a feeding pattern has become established. If you are growing a crop, for example, you need to know what bird species are likely to cause damage, and when they first visit your crop, so that you can start a scaring campaign without delay. However, it may be very difficult, or impossible, to keep birds out of a crop if there are no alternative food sources.
Destruction of Wildlife
Destroying a few individuals will rarely solve a damage problem, and reduction of the problem is not proportional to the number of animals killed. At best, killing of animals usually provides only short-term relief and is very labour intensive, as well as being distasteful to most people. Most species of wildlife which may cause damage are adapted to withstand considerable levels of mortality without the population as a whole being affected. Thus the capacity of the population to produce young each year is unlikely to be affected by any but the most intensive destruction campaigns.
Such campaigns are not likely to be permitted by DPI/DSE. It is sensible, therefore, in the case of problems which are likely to recur regularly, to look for longer-term solutions to control damage, such as exclusion, different crop placement or other, non-attractive crops, rather than killing.
Direct control of wildlife through dispersal, trapping or destruction of wildlife is managed under the Authority to Control Wildlife system (ATCW). The following fact sheet outlines the ATCW system, how it works and why it is needed.
Authorities to Control Wildlife - Fact Sheet (PDF - 124 KB)
From time to time, commercial harvest of wild kangaroos in Victoria is raised as an idea by individuals and stakeholders in response to a perceived overabundance problem in a specific local area. There is no commercial kangaroo industry in Victoria and it is government policy not to develop one.This Fact Sheet outlines the reasons why Victoria does not support this.
Harvesting of Wild Kangaroos for commercial purposes - Fact Sheet (PDF - 105 KB)
Relocation of Wildlife
It often seems that the best way to solve a problem being caused by wildlife is to catch and relocate the wildlife. However, this is seldom the case. Some of the reasons for this are discussed briefly here.
Within any habitat, factors such as availability of food, nesting or roosting sites, or frequency of interactions within or between species will determine the numbers of a species which that habitat will support.
Release of an animal into a habitat already fully occupied by that species is likely to result in the relocated animal either not being able to find suitable shelter, being stressed by aggressive interactions with its own kind, or displacing a resident animal. The introduced individual is likely to have a greater exposure to predators during this period. Starvation is likely to result from the introduction of a mammal to an area in which the food species are not those to which it is accustomed.
As a general rule, if a species does not naturally occur in an area it is a good indication that the area may be unsuitable for that species and should not be considered as a release site. Introduction of a species to an area recovering from fire could result in adverse impacts on the habitat, or in the starvation of the introduced animals due to lack of suitable foods. Introduction of an animal from elsewhere into a population of a sedentary species could result in the genetic contamination of that population, with possible adverse impacts on future generations. With many species of birds and some mammals, relocation makes little sense. Most bird species are highly mobile, and new individuals will continue to be drawn to an attractive food source. Similarly, relocation of a possum from a house roof will simply make way for another possum to move in.
Prevention of access to the source of attraction is the sensible solution to these kinds of problems. An exception would be in cases where individual birds or mammals develop unacceptable habits. For example, a Kookaburra which repeatedly attacks windows should be captured and removed. Since relocation of such a social and territorial species is likely to result in its death, it would be more humane to have it put down, under permit from DPI/DSE.
Finally, relocation may pose a very real risk of diseases being transmitted to wild populations of a species, particularly if the animal being released has been kept in captivity, and/or has been in contact with other captive animals including domestic dogs or cats. In situations where relocation is likely to result in the death of the animal being relocated; in adverse impacts on other species, or in damage to the habitat of the release area, then destruction authorised by DPI/DSE, rather than relocation of the problem animal(s), should be considered, if the problem cannot be resolved by other means.
