There is no disputing that telemetry is a great asset to the modern falconer. It is not merely useful for locating hawks that have been lost through unfortunate circumstances whilst flying, but also for finding hawks on kills. There are several systems currently marketed. The first point to bear in mind is that units, even from the same supplier, seem to vary enormously. Each supplier, therefore, will have the blessing of some of his clientele and the damnation of others. The strengths and weaknesses of a receiver unit lie in the following areas:
1) Range This will vary according to the area in which the hawk is being flown. Obviously the more open the area, the greater the range of a particular unit. Trees, built up areas, hills and electrical pylons, will all cause a reduction of the range over which the system will effectively operate. Generally speaking, a greater ranger is required for longwings than for shortwings.
2) Directional finding Some receivers fall down in their ability to find a hawk at close range. They will give a strong signal to let you know that the hawk is close by, but will not allow you to pinpoint her exact location. Contrary to what you may expect, the gain or volume knob should be repeatedly turned down as low as possible, for if it is on too high a setting, the signal will be received over such a wide arc that the operator will not know in which direction to search. Some units will enable the operator to disconnect the antenna lead when at really close quarters and to use the end of the lead to track down the precise location of the hawk, which may be necessary if she has killed in dense cover.
3) Portability If a unit is to be of any real use, it should be able to be carried easily by the falconer when in the field. Many units fall down in this respect. Valuable time and distance can be lost if the falconer has to return to his car, or, still worse, home, in order to pick up his unit.
4) Easy assembly The antenna is collapsed when not in use. Some units have a system of rods to be slotted into place. All this takes time – the antennae that open out from fixed points are infinitely quicker and less irritating. Better still are the units which have the antenna actually mounted on the receiver itself and which can be pointed, like a gun, in the direction in which the hawk disappeared.
5) Channel selection Telemetry units have a number of channels, which enable the user to operate several transmitters at the same time. It is therefore important that the channels are not too together on the waveband, lest there is overlap. A fine-tuning knob enables the operator to tune into each transmitter so that the best signal is received. The easiest receivers to operate are those with numbered push-button channel selection. In practice, if a hawk is lost at a time when a number of other hawks are fitted with transmitters, it is best to collapse the other transmitters before seeking the lost hawk. This prevents any possible confusion – one does not want to spend several hours attempting to locate the hawk sitting on the fist of one’s companion.
6) Needle meter When the wind is howling, as is so often the case when one is in pursuit of a lost hawk, it is most depressing if one is unable to hear the beep because it is drowned out by wind. In such circumstances, a meter indicating the strength of the signal by means of a moving needle will come into its own.
7)
Additional features A
unit should have a socket for earphones, which will help enormously in gale
conditions. It is also helpful to
have a unit, which can be powered, by a socket inserted into the cigar lighter
of a car. A magnetically mounted
car-roof aerial (magmount) can then be utilized to help the falconer search over
long distances, for when no signal is received it is the unhappy task of the
falconer to travel with grim determination in the direction in which the hawk
was last seen disappearing, until she cones into range.
If this approach fails, he must then broaden his search in a wide arc in
an attempt to pick up a signal.
Batteries should be removed from a unit at the end of the season, for they may corrode and damage it. The size of the transmitters is in direct proportion to the size of the batteries. Depending on the size of the hawk and how much weight one feels it can carry, the choice of transmitter varies from single stage (one battery) to three stage (two batteries and two aerials). It is worth being extravagant with batteries, for the life left in them dictates how long one has to find a lost hawk. Lithium batteries last much longer and are suitable for larger transmitters.
Transmitters are attached daily before flying and removed immediately afterwards so that the batteries can be taken out. Consequently, an easy and safe way of attaching the transmitter has to be adopted. The falconer has the choice of attaching it either to the tail or leg. There are pros and cons with each option. On the leg, the hawk may well remove the aerial. In the field, this will reduce the range to the point where the transmitter is, to all intents and purposes, useless. It may also impede footing. If the transmitter is tail mounted, it is not unheard of for the falconer to track his absent charge, only to pin down the deck feather(s) to which it has been attached, swinging, complete with transmitter, on a barbed fence. However, better the loss of the deck feathers than a wrenched leg. Tail-mounting therefore seems the preferable option. There are two principle methods of attaching a transmitter, dependant on the design. If the transmitter has a metal keeper at the top, an electrical cable tie can be passed through this and slipped through the tail bell mount or the almery. Cable ties are the only safe ties to use for attaching transmitters in this fashion. Unfortunately, a cable tie is used and cut off every time the transmitter is attached, but the very small type of cable tie suitable for this operation is relatively inexpensive.
The alternative method of mounting can be employed if the transmitter is fitted with a spring-clip system. These are designed exclusively for use on the tail. They are supplied with a small metal tube, which is glued around a deck feather. The clip is then squeezed with the fingers and pushed into the tube, opening up when released to hold it in place. In theory, this sounds like an excellent idea, as it saves wasting a cable tie each time the transmitter is used. In practice, however, its ease of used depends largely upon the hawk – some, when keen, simply will not hold still long enough to enable the little prongs of the spring clip to be lined up with the tube on the tail.
There are two principle types of transmitter - the type where the batteries are pushed into a brass holding slot and the cap-and-barrel variety. The first type, where the batteries are pushed into place and secured with a surrounding rubber loop, are better. The cap-and-barrel variety, where the batteries are dripped into the barrel the right way up before the cap is screwed into place, have a tendency to loosen a fraction while hawk is on the wing, breaking the contact point between the base of the barrel and the positive terminal of the battery.
The crystal determines the exact frequency of the transmitter. Different frequencies require different lengths of aerial. From the falconer’s point of view, the shorter the aerial the better, lest it should impede the hawk’s progress. In the UK, of the tow frequencies usually marketed by telemetry firms, 216 MHz is illegal, but requires shorter antennae, both on the receiver unit and on the transmitter, than the other legal frequency usually encountered – 173 MHz. It is important that all transmitter antennae are coated in plastic so that they cannot blow up if they should trail down against an electrical wire.
Telemetry does not guarantee the safe return of a hawk. The use of telemetry however expensive and effective the system, is no substitute for sound training and proper practices. It is essential to practice with a unit before entrusting the hawk to the façade of security it represents.
With such dangerous conclusions long term tracking through telemetry has had mixed results. A radio collar or tracking device placed on a bird such as the Peregrine Falcon must be tolerant of high speeds, play little effect in prey seizes and also be able to transmit with some efficiency to get accurate data. Not only that, but the birds themselves have risks associated with wild bandings as well. Breaking a feather can cause it to bleed, or banding may be too tight so it will loose a leg. In the wild banding and tracking devices are hard to do because of the relative proximity of the nest. They are usually in very hard to locate places. However, in many pre-established homes, like in skyscrapers, nesting cameras can be set up to view the success without much disturbance. It’s usually better to keep as little human influence out of a nest as possible to protect the young ones. If the parents, although they are furious guardians and good caretakers, are not able to return to the nest for a day or more with food the poor chicks may starve. Also there is a too early too late motivation with wild populations. Timing is absolutely crucial, if its too early the chicks may be left without their parents, if its too late, the fledgling may try to get away and end up taking a tumble or injury before it is quite ready to fly. All of this must be considered to be taken into account when working with wild populations. But the main factor in those with telemetry and similar mountings is that the bird may loose feathers, and or a leg. Is it worth the risk or is it in this case a plea for observation over technology.
