As more and more geese with GPS-loggers are being spotted in the Netherlands, I became more curious to know what data they carried in those GPS backpacks. Many people use satellite tags to track birds, as these will automatically send the data to your computer no matter where the bird is. The tags we use are loggers, an thus only store the data. Downloading the data from these loggers can be done remotely using an antenna connected to a laptop, but you still need to be rather close to the goose (500m). In order to do this, you first need to find the bird before you can download the data.

Because in total 4 of my geese with GPS-loggers had been sighted in south-western Friesland, I decided that this would be the first place to try and download data. Me and Thijs Fijen therefore planned a long weekend around Akkrum. We started driving around in farmlands where many small groups of Barnacle Geese were foraging. It did not take long before our antenna picked up the signal of a logger-goose close to a farm, we soon spotted the goose W1N6 in a small flock. Although we could stay close to the goose for over 2 hours (and were even offered coffee and biscuits from the people in the farm) we were not able to download more than 150 kb of data before the goose flew off. Too bad. We resumed our journey to Vegelingsoord were a huge flock a geese was resting close to a nature area, but did not see or track any goose with a GPS-logger. In the end of the afternoon we returned to Akkrum where a big flock of geese was present. The system soon picked up another GPS logger goose, W1NJ, and we were able to download 500 kb of data before the flock suddenly flew off. The sun was setting, and we returned home, happy to have found 2 geese and to see that the geese seemed to be in good condition. The next day we returned, but were unable to find any logger-geese. Although we were able to download some data during the weekend, this data was only from movements on the breeding grounds, and no data on the migration routes of the geese.

On the island of Schiermonnikoog researchers from the University of Groningen (RUG), Netherlands Institute for Sea Reasearch (NIOZ) and SOVON have for long been doing research on spooonbills and oystercatchers, which have been equipped with similar GPS-loggers as our geese, also from the Universty of Amsterdam. These researchers are also tracking their birds with the same antenna system, and had set up this system in early spring of this year. After setting-up, goose W1NE which had already been seen once on the island around Christmas, was soon picked up by the system and was sending data! After some days we got enough data to get an idea of the movements on the breeding grounds but also the migratory route of this goose. Last week I received the last part of the data, we now have a complete overview what this goose has been doing for the last winter. Apparently it visited Schiermonnikoog only for 2 weeks during Christmas, after it made a winter trip to Groningen and Zeeland, before it came back to Schiermonnikoog in early March.

Also, we have the first picture of a logger-goose in the Netherlands. Peter Matthijsen managed to photograph LAB5 and her partner in the Westplaat Buitengronden.