by Michael Dunbar
The author works with the Nature Conservation
Bureau Ltd. in Britain which has taken a special interest in satellite
tracking of wildlife. We asked him to tell us where this exciting technology
is heading and how it can be used to help conserve Arabian wildlife.
What do emperor penguins
from the Antarctic; grey seals around the shores of Britain and houbara
bustards in southern Arabia all have in common? Not much you might say,
except for the fact that they have each been tracked using space-age technology.
The problem of following emperor penguins through the bitterly cold Antarctic
winter eluded biologists until French researchers fitted the penguins with
satellite tags. Since the penguins were living on pack ice the information
on their own movements was compared with remote sensing imagery which revealed
fluctuating conditions of the ice itself. The result was that scientists
sitting in their comfortable laboratories back in France were able to report
that, after four months without food, in the deepest of winter conditions,
the penguins walked continuously, night and day, over a distance of 100
kilometres in order to reach ice-free areas where it is supposed that the
penguins were able to feed. The difficulties of studying this behaviour
in the field have made the satellite tracking technology of special value
to biologists investigating this and other aspects of the Antarctic’s wildlife.
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.