If the weight of a caught crane is more than 3000 g, sometimes a transmitter is additionally attached beside the colorings. This transmitter has a weight of about 60 g and will be attached as a backpack with a 1 cm wide elastic rubber band around its body. Every radio transmitter has its own frequency.
Every 1.5 seconds the transmitter is sending a specific radio impulse, that can be can received with special radio receivers. The frequency is ranging between 148 and 149 MHz. Depending on the vegetation cover and relief the transmitters can be detected in a range of 2 to 7 kilometers. Radio transmitters usually last for three to four years.
Godfathers from all over Germany sponsor such radio tags, are allowed to give names to “their” cranes and can follow their birds in the iCORA database.
The information from such radio tags is important to learn more about the habitat and site use of cranes and can be used for conservation activities, e.g. during land-use planning.
Radio telemetry data for land use planning
What is the size of a crane territory that is needed for a successful rearing the offspring? Which feeding areas do they prefer? How are these feeding areas structured and which are the influences of different kinds of disturbances? With the help of the telemetry we can get answers to these questions.
Some results for example show that in the region of the “Mecklenburg Lake district” crane families used a territory of about 80.5 ha (n=19) for a successful rearing the offspring in the years from 1995 to 2000.
In 2013 the German Crane Working Group for the first time used three GPS transmitters from the e-obs company. This manufacturer is specialized on lightweight GPS transmitters for marking birds and mammals.
These transmitters use the GSM (Global System for Mobile Communications) system, which allows sending SMS with their positions. Every day each transmitter sends a SMS with five positions (coordinates) of the crane to the NABU-Crane Centre in Groß Mohrdorf. With this technique it is possible to get information about the exact position and the movement pattern of these cranes. This also allows scientists to study their birds without extra field work.
Additionally the new transmitters, which weight only about 56 g, are equipped with a 3D-movement sensor. The sensor is integrated in the transmitter on the cranes back and records the slope of three axes. Because of the shift of the axial inclination per time we can get conclusions about the behavior of the crane.
Another advantage of these new transmitters is the solar panel on the top of the GPS-GSM transmitter. So the energy for data collection is not used from batteries but from the sun. Theoretically this energy is endless available.
Due to sponsorships we were able to use further GPS-GSM transmitters. If you would like to support our work with a LIVE-project-sponsorship, please contact us.