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Radio-marking of Common Cranes in Europe

Marking cranes with radio-transmitters begun in Spain in 1988, in Germany in 1995, in Israel in 1997, in Estonia in 1999 and in Poland and Sweden in 2001. Depending on the way they are attached to the bird, transmitters are of two types: one is called "backpack", and is attached to the back of the bird by means of a harness, the antenna pointig backwards, and the other one called "leg-transmitter", attached to the bird's tibia, usually mounted on a long ring, with the antenna pointing downwards, hanging along the leg while the bird is standing. Backpacks were attached to the birds following procedures described by R. Kenward (1979). Raptor radio-tracking and telemetry, pp.409-420, in Newton, I. and R.D. Chancelor (eds.) Conservation studies on raptors. ICEP Tech. Publ. Nr 5)

JAA

Schematic drawing of the two existing types of transmitters, (left) backpack and (right) leg-transmitters. Backpacks are attached with a harness to the back of the bird, and usually remain covered by the feathers; leg transmitters are attached to the left tibia when marked outside their breeding areas or to the country long band when breeding country is known

A backpack (left) and a leg-mount (right) transmitters on German young birds
(Pictures H. Dirks)

In relation to their source of energy, there are also two types of transmitters, both similar in shape and colour. Transmitters can be solar-powered (see picture), although most of them are battery powered.

Both types can be attached either to the back or to the leg of the bird. Leg transmitters used in wintering grounds are always on left tibias; those employed in the breeding areas are attached to the country code rings or country long band.

(Picture J.C. Alonso)

A satellite transmitter also suitable for conventional radiotracking

A backpack solar powered satellite transmitter. Note that this transmitter has two antennas: a long thin horizontal satellite antenna, pointing backwards, and a short VHF antenna, pointing upwards, for conventional tracking.
(Picture J.A. Alonso)

Another example: In the picture it is possible to see one of these leg-transmitters mounted on the left tibia by means of plastic strips to attach it to a long yellow ring. The antenna is divided in two sectors. pointing respectively upwards and downwards, because its length is higher than that of the of the bird tarsus.

The type of transmitters used in each case depends on the different objectives of the projects developed in each country. In Spain, for instance, almost all the transmitters were conventional battery powered, apart from some used to test them and for comparison. The main objective of radio- marking was to allow observers to remain in visual contact with the studied birds as long as possible during the winter season. Solar powered transmitters, used at the beginning of the study were not used afterwards as we observed that they din't work properly when the temperature drops well bellow 0ºC, a common circumstance during winter. In Israel, on the other hand, all the transmitters used up to now are solar powered satellite transmitters (see previous picture), because the main objectives were to know (a) the migratory routes, (b) the staging areas and (c) the location of the breeding grounds. Nevertheless most of the transmitters employed are still conventional battery powered units, with an expected life of 3-5 years. (See More information on radio-tracking materials and tecniques).

All the transmitters used work in the 148.000-149.999 MHz band. Signals are regular "beeps" at a rate of 30-40 b.p.m., i.e. one beep every 1.5 seconds aproximately.

You can get the List of Frequencies of conventional (not satellite) transmitters that are still beeping (regularly updated by JAA, with information provided by national banding coordinators).

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