Grey seals living off the east coast of the United Kingdom have been tracked by the use of similar technology by members of the Sea Mammal Research Unit. The scientists were thus able to demonstrate that seals can find their way quite easily from one hauling out site to another one 250 kms away from the first. They did this while swimming offshore, out of sight of land, and kept to an almost identical course on several such satellite tracked journeys. Needless to say, the scientists were able to acquire this fascinating insight into the seal's navigational abilities whilst drinking their tea in their laboratory!

The technology is also being used within Arabia where, for example, houbara bustards have been fitted with lightweight satellite tags by researchers at the National Avian Research Centre in Abu Dhabi. Initial trials were carried out on houbara within large fenced enclosures and more recently the tags have been fitted to both wild and captive bred birds that have been released. In one such experiment a wild female was followed for a period of 62 days. During this prolonged period the scientists were twice able to go to the place where the satellite tracking reported the bird to have been last recorded and to then use a sophisticated electronic receiver to locate the wild bird and to take a closer look at it to see how it was managing. On the second such occasion they could se that the tag was nearing the end of its useful life and they were able to recapture the bird and to remove the tag.

The researchers hope that this advanced technology will permit them to follow the migrating birds as they fly between their breeding grounds in central Asia and their over-wintering grounds in Arabia. They will thus be able to see precisely where the birds go to breed and which routes they follow. Clearly, such information can be of crucial value to future conservation programmes and the UAE team is keen to understand more about the houbara's life-history in order to assess the comparative values of various potential conservation strategies.

Arabia is an ideal area of the world for such satellite tracking studies since vast areas of the peninsula are extremely difficult to access and weather conditions make prolonged field trips arduous and in some cases even dangerous. Although this technology cannot replace the need for good field-work, it can greatly extend the scope of biological studies and reveal information that would be otherwise extremely difficult, or in some cases even impossible, to obtain by any other means.

One of the prime concerns of scientists involved in this work is for the welfare of the animals themselves. For this reason careful studies are made of any possible effects of the tags on the animals before work is conducted in the wild. As the work proceeds any possible effects are carefully noted and their implications are assessed. Over time a body of information has been built up and it is increasingly possible to make judgements on suitable methods for tagging species that have not so far been tracked in this way.

At the present time all such animal tracking uses the Argos satellite system. One can track the animal from the comfort of the laboratory and it makes no difference if you happen to be a few metres away from the animal or thousands of kilometres away. All that is required to receive the latest report on locations for a particular tagged animal is a personal computer, a suitable modem and a telephone line. It is even possible to receive the information directly from the satellite, using a suitably tuned satellite dish.

Several organisations are currently engaged in this work. The Nature Conservation Bureau, based in Newbury, England, has a wide range of skills in habitat and species management as well as in coordinating international projects in the field of conservation. They were responsible for the first remote tracking of houbara bustard using UK-designed bird-born transmitters, in conjunction with the National Commission for Wildlife Conservation & Development in Saudi Arabia. More recently they have been involved in satellite tracking carried out by the National Avian Research Centre in Abu Dhabi. Not only can they conduct studies on animal movements but they have the capability to advise on the special characteristics of the Argos system itself; an element that is often over looked but is essential to maximising the performance from the system.

The Argos system comprises two polar-orbiting satellites jointly operated by NOAA in the United States, and CNES in France. Tagging programmes involve the use of these two satellites, a PTT or platform transmitter terminal (in other words the tag that is placed on the animal); fixed ground stations for receiving the signals from the satellite and sending positioning information to the user; or, in some cases, mobile ground stations that receive information directly from the satellite. From the transmitter's viewpoint the satellite will rise above and set below the horizon in less than 14 minutes. During this period the satellite will receive a number of ultra-high frequency (UHF) radio pulses from the PTT and the signal will change due to the Doppler-shift. The details of these frequency changes are relayed to the ground station and are further processed by powerful computers at the Argos headquarters in Toulouse. The final result is an accurate positioning of the PTT or, in this case, the animal bearing the tag.

Every tracking assignment has its particular characteristics and potential problems. Good training is an essential pre-requisite. In each case the tags themselves must be carefully customised to the particular animal. Apart from the housing for the electronics component, the tag comprises a special means of attachment to the animal, an on/off cycle control and an antenna. All must be correctly tuned and adjusted for the system to work properly. Needless to say, the minimisation of weight is of crucial importance in most tagging operations and technology is helping in this with improved batteries and microelectronic circuitry. The aim is to achieve longer and longer working lives for tags once they are fitted and we are seeing constant improvements in this area.

There is no doubt that satellite tracking of wildlife is here to stay. The thought that it might be used to help save the Arabian leopard, or to re-establish the houbara bustard, or as a means of tracking oryx as they once more run free in the Rub al Khali is a fine reward for all the work and effort that has gone into this work.

Further information on the hitech wildlife tracking can be obtained by writing directly to the author at The Nature Conservation Bureau Ltd., 36 Kingfisher Court, Hambridge Road, Newbury, Berkshire RG14 5SJ, UK. Fax (+44) 1635 550230.