Wild animals are as they are – anatomically, physiologically, immunologically and behaviourally – as a result of the continuing process of natural selection of those best-adapted to the environment, and we should be wary of interfering with this process.
However, many wild animal casualties are due to man’s very recent (in evolutionary terms) changes to the environment, and may be caused by for example: road traffic accidents, oil spillage at sea, collisions with high tension wires, and poisoning by environmental contaminants. In these cases the argument for rehabilitation is particularly strong.
Concern for animal welfare and species conservation underlie efforts to treat wild animals and restore them to the wild. Whilst, in some cases, the restoration of an animal to the wild may benefit both the individual and the species, there are circumstances when neither animal welfare nor conservation are served by attempts to rehabilitate.
Careful thought needs to be given to each case and the purpose of these documents is to provide some guidelines about ethical and legal aspects of wild animal treatment and rehabilitation.
The Ethics of Wild Animal Treatment and Rehabilitation
This is a very difficult subject and opinions differ widely about what is and is not a justifiable level of intervention in the fate of individuals and thus the population dynamics of their species.
A good first principle which also guides medical and veterinary practitioners, but which also applies here, is “first, do no harm.”
There are several ways in which inappropriate rehabilitation attempts may also do harm – either to the individual involved, to others of its own species, to other species, or to the environment. It is important that these possibilities, examples which are listed below, are considered:
- If the animal is not fit when released, and suffers as a result
- If a fit animal is released into an inhospitable environment (e.g. one in which food is scarce, or in which all territories are already occupied)
- If a released animal carries an infectious disease, which could spread into the wild population of it’s own or other species
- If it is a genetically distinct strain from those in the area where it is released, in which case its offspring may be less adapted to the local environment
- If it is a non-indigenous species which may damage the ecosystem
- If it displaces a resident of the same species, to the latter’s detriment.
The welfare issues (points 1 and 2) are the most immediate, and perhaps the most easily judged, and must be carefully considered in each case. The genetic arguments are probably of little relevance in most cases involving common species, because rehabilitated animals are unlikely to form more than a tiny proportion of the breeding population. The potential for introducing infectious disease into the wild population demands consideration because of the opportunities for cross-species disease spread in wild animal hospitals, and the effects of introducing disease into wild populations could be serious. Both genetic and disease hazards could be particularly relevant when rehabilitating an individual far from the site where it was captured.
Rehabilitation of wild animal casualties can for these reasons be harmful, and these considerations must be seriously addressed.
The law permits taking sick or injured animals for treatment, although in the case of birds, only if the intention is that they are released when cured (see note on legal aspects below).
The preceding paragraphs point out that treatment and rehabilitation of injured or sick wild animals is not, in all cases, the kindest or wisest course of action. Practical and economic constraints alone dictate that not all rescued individuals of all species can be treated and rehabilitated. Maintenance in captivity or euthanasia are humane alternatives. Some circumstances under which rescue, treatment and rehabilitation may benefit the individual, and/or its own or other species are listed below:
- If the individual, having been restored to complete fitness, is successfully reintroduced into habitat that can support it, without compromising the success of other wild individuals. That is, if the wild population is smaller than that which the environment can sustain (as may occur after a ‘die-off’ due to bad weather, a disease epidemic, environmental contamination, or persecution); or
- If what is learned in the process of treatment and rehabilitation may subsequently be of value in the care of individuals of rare and endangered species in the future.
Three criteria should be addressed before embarking on treatment and rehabilitation, namely; whether or not the attempt will improve welfare, conservation, or knowledge. From the welfare viewpoint, it is not easy to judge whether treatment and rehabilitation is preferable to humane euthanasia. Even when successful, treatment is unlikely to be accomplished without any fear, pain or stress.
The welfare of the individual must be prime consideration, but it is appropriate to consider also the conservation status of the species.
With the exception of a few rare British species, rescue and rehabilitation is unlikely to have direct beneficial or harmful effects on population dynamics. However the rescue, treatment, and rehabilitation of wild animals provides an excellent opportunity to learn about their diseases, management, medical care, and husbandry, which may contribute to conservation in the future. This time and level of organisation required to collect, analyse, and publish results, and thus capitalise on the work in this way should not be underestimated.
Preventative Wildlife Medicine
It is perhaps a small step from treating the common causes of diseases and injury in casualty animals, to considering how these ills might be prevented. If the cause is man-made, for example environmental pollution, then steps should be taken to correct the situation.
It is probably not justifiable, on the other hand, to interfere with the epidemiology of ‘natural’ diseases by, for example, vaccination or routine anthelminthic treatment of free-living animals, unless this forms part of a scheme to prevent disease in man or his domestic livestock (e.g. vaccination of badgers against tuberculosis), or perhaps to intervene to protect an endangered population (e.g. vaccination of mountain gorillas against measles).