Latest technology for Black Storks
How Satellite Transmitters work and what is behind:
The Black Stork transmitters are state of the art high-tech equipment, which are used in this implementation for the first time for Black Storks. They make it possible for the first time to record and analyse high-resolution, three-dimensional GPS data (longitude, latitude, and altitude), as well as movement patterns of storks.
The transmitters of German company e-obs
weigh 57 grams and consist of several components, which are assembled in a weatherproof, durable plastic case. Just like a regular hand-held GPS device used by hikers, the transmitter records the GPS data of the stork with the help of satellites. This can occur even every 30 seconds, and thus shows a gapless record of the flight of the stork, depending on the battery voltage and memory status. This allows us to better assess the hazard potential of wind turbines and locate the preferred foraging habitats of storks.
In addition to GPS positions, these transmitters can also detect and store three-dimensional motion pattern of storks. Like this it is possible to determine by the line patterns whether the stork is active, stands or lies or if he beats his wings or is gliding in the thermals.
A Storklet with the "backpack" and the movement lines(Photo from the project website, ©H. Röhl)
Excerpt of movement data of Stork 1(Photo from the project website, ©H. Röhl)
The best part is that the transmitter battery is charged again and again by a solar module. Like this the transmitter theoretically lasts for a stork's lifetime. Thus we are able, provided our storks survive the diverse dangers, follow a storklet live for many years, from its first exploration flights, over its migration routes to the south, the wintering areas in Africa and its first breeding attempt here in Europe, to its death.
Until now similar projects have been difficult as one had to follow the animals for retrieving the data. Because only with a hand-held scanner and an antenna and in relative proximity to the animal, it was possible to establish a connection to the transmitter and download the data. Our transmitters on the other hand use today's globally distributed and well-developed mobile network. If the stork is in an area with good mobile phone network, he will transmit all data once a day encrypted to a specific website, from where we from LBV look at the data and can process them further. Even you can globally follow animals fitted with transmitters live: http://www.movebank.org
Should the transmitter at some occasion have no good network, it will send an SMS with the last five GPS positions to the Move Bank, so if in doubt, one still can follow the animal and read the data using the hand-held scanner. The data storage is large enough to save data of up to one year, so even after wintering in Africa no data will be lost. Once the transmitter has again mobile network reception, it will send all collected GPS positions and movement profiles to the Movebank.
The transmitter is attached like a backpack to the Black Stork using a Teflon tape. The material is especially skin friendly and weatherproof, so it is not chafing and should survive a stork's lifetime. This system has already been proven in a similar project with Latvian Black Storks. Including the Teflon straps and metal crimps, which ensure that the strap is not detaching from the transmitter, the whole backpack weighs a little less than 70g. This corresponds to about two to three percent of the stork's body weight. Putting on the transmitters
In order to put transmitters on Black Storks, one has to aim high. Because you can capture the elusive animals best when they can't fly yet, still sit as hatchlings in the nest on the brooding tree. To make sure the backpack is not too large but fits perfectly, one has to wait until the young ones are shortly before leaving the nest, are so to say "teenagers". With 50 days they are big enough for the backpack and at the same time still "small" enough not to jump out of the nest.
Then professional tree climbers of the Bayerische Staatsforsten
(Bavarian State Forests) climb up the nest tree. There they carefully pack up the storklets individually into cloth bags and let them slowly down to the ground by rope, where they are received by the LBV researchers. Before the backpack is adjusted, each stork is measured, weighed and ringed. The data provide information about the nutritional condition and can be used for comparison with other locations. The special ELSA stork rings of the ornithological institute Radolfzell can be read easily, even from great distances and thus help with identification if the Black Storks are spotted. The siblings of the transmitter storks get these rings.
The backpack system with the transmitter is carefully applied and checked several times for its proper fit. After all, it must fit perfectly for years. After this, all the storklets are again pulled up in the cloth bags to the nest and put back. The whole operation lasts for about 45 minutes and great care is taken that the parents are not aware of it. They are foraging for their ever-hungry brood all day and usually come back to the nest only after four to five hours for a short feeding.Translation of the LBV website about the Black Stork transmitters: http://www.lbv.de/unsere-arbeit/vogelschutz/schwarzstorch/modernste-satelliten-technik.html With thanks to H. Röhl for the permission to translate it - Felis silvestris