Introduction

Considerations of care and handling of pups in rehabilitation must relate to the natural behaviour of pups of comparable age in the wild, and how the pup will adapt to life in the wild after its release from rehabilitation. We will consider separately various aspects of rehabilitation practice and how these compare with the experience of a pup reared naturally in the wild.

Time in rehab

Time in rehabilitation should always be as short as possible. This is because seal pups develop very rapidly in the wild, and pups in the wild therefore undergo a very steep learning curve during the first months of life, and most particularly during the first weeks after weaning. Harbour (common) seal pups are weaned at 3-4 weeks of age and research has shown that almost all pups have learned how to forage for their own live prey about two weeks after weaning, and are catching enough food to maintain their weight and grow from a month after weaning. If pups are kept in rehabilitation throughout this sensitive age of 4-8+ weeks, they are obviously missing out on this essential learning opportunity in the wild. Feeding per se is also not the sole consideration. Pups at this age are also learning social skills as they integrate into the local population and geographical knowledge of their future home range. By contrast, a pup of this age held in a rehab environment is not only missing out on the natural learning curve, but may be acquiring patterns of behaviour and orientation which could interfere with appropriate behaviour after release.

It is for this reason that we try to release our pups as soon as possible after the natural age of weaning. It is not possible, with the present feeding recipe, to match the natural 3-4 week nursing period for harbour seal pups. Our pups gain on average about 0.3 kg/day, whereas a wild pup gains about 0.5 kg/day, and some of our pups are very underweight to start with. Nevertheless, we have found that it is possible in most cases to get pups to an acceptable release weight (20-21 kg) after 4-6 weeks, sometime between the end of July and the middle of August. This enables the pups to be released at a time when most of their wild pup peers are still close to the haul-out groups of moulting adults, and still at the stage of learning to feed on tiny inshore fish. Thus although our pups are a little late joining in with the others, they are not too, and this ihas been confirmed by our radio-tracking. Wild pups end to disperse to foraging sites further offshore from late August-early September. It is probably important for rehab pups to join this dispersal after they have benefited from a few weeks of inshore feeding and orientation experience.

Our experience has been all with harbour seal pups. It is important to note that the same principles - of dove-tailing rehab pups development with pup development in the wild - will apply to other species, although weaning time and weight

Type of feeding in rehab

It is important for rehab facilities to recognise that wild seal pups never normally eat prey that they have not caught and killed themselves. they do not go through a weaning stage (like wild cats and dogs) of eating dead prey brought to them by their mother. So far as we know, they make a transition directly from nursing from their mother to independent foraging for small, live prey.

Therefore, when caring for a pup of nursing or weaning age in rehab, it should be understood that it is not following a natural pattern to train the pup to eat dead fish. It is a frequent misconception in rehab centres that a nursing pup should be 'weaned on to solids', and that successful training of pups to take dead fish in rehab will somehow help them to adapt to independent life in the wild after their release. It will not - in fact a pup so-trained will have to 'unlearn' the rehab fish-feeding pattern and substitute the totally new pattern of foraging behaviour and catching live prey.

It is for this reason that we feed pups only a milk formula until their release. This mirrors the natural situation of nursing from the mother until weaning and nutritional independence. Our tracking studies have shown that our pups make the transition to normal diving and foraging behaviour immediately after release.

We have used the milk formula successfully in feeding two pups who were from about 6-9 weeks of age in rehab (Cecilia - 1996, and Leo - 2001), and one pup for a few days in November. a four months of age (Olly - 2002). However, for a pup taken into rehab at 3 months of age or older, it may be less detrimental to feed it on dead fish (if that is more convenient for the carer), since the pup will probably alrealy have established natural feeding patterns; however, the period of rehab should be kept as short as possible in order for the natural feeding pattern not to be lost.

This issue is particularly important to the feeding of grey seal pups in rehab. Grey seals seem to be more opportunistic in their feeding patterns than harbour seals, and very easily learn 'aberrant' feeding patterns, such as feeding from fish scraps in harbours, following fishing boats, and raiding fishing nets and fresh-baited creels. A grey seal that has been trained to eat dead fish in rehab may be more likely to adopt this type of feeding strategy after release, which may lead it into conflict with fishermen and possibly an untimely death.