by Allert Bijleveld, Evy Gobbens & Emma Penning

We use WATLAS (www.nioz.nl/watlas) to track birds and study their ecology and behaviour in the Wadden Sea. This summer young spoonbills were tracked too, in a first attempt to follow their dispersal away from the Griend colony where they hatched. Small 4g WATLAS-tags were glued to their lower back and were expected to fall off after about two months. To track those spoonbills after leaving the Wadden Sea, some were also equipped with a GPS-transmitter also. This turned out to be a smart move because the young spoonbills managed to get rid of their WATLAS-tags! Thanks to color-ring resightings and localizations of the transmitters that were applied simultaneously we could confirm that it was a matter of WATLAS-tag loss and not mortality. Next year we will need to come up with a better tag-attachment method for these agile birds.

Later on in August we set up a catching expedition with the aim to catch and tag a range of shorebird species. At different sites around the island Griend, we caught over 140 shorebirds that are now tracked at high resolution in the western Wadden Sea. Shorebirds in the Wadden Sea are always on the move due to the continuously changing water levels, this results in the most beautiful and fascinating movement patterns. Go and see for yourself at:www.nioz.nl/watlas. Looking at each species, we already notice how some specific mudflat areas are being used. Fecal samples were collected during catching to establish species specific diets and were looking forward to disentangle if species specific movements are related to prey preference. This specific expedition was part of Evy Gobbens’ PhD project. Find out more on www.nioz.nl/watlas and Evy’s blog.