Ronny found back, three years after deployment of the UvA-BiTS GPS-tracker
Wednesday, July 8th, 2015
Species: Montagu's Harrier
Project: Conservation of Montagu’s Harrier
Male Montagu’s Harrier Ronny was captured and fitted with an UvA-BiTS GPS-tracker in Eastern Groningen, The Netherlands, on 27 May 2012. After releasing Ronny, we never got any signal ever after. Caught at a place where several breeding pairs were concentrated, we were very unhappy to realize that this 3rd calendar-year male was a non-breeder and would not contribute to our research on habitat use during the breeding season.
But in the end we were fortunate! Our German colleague Friedhelm Niemeyer, who is in charge of the Montagu’s Harrier monitoring and protection in the region around Diepholzer Moorniederung in Lower Saxony, Germany, observed a tagged male in the beginning of the breeding season this year. Of course we didn’t know who it was, since we never heard of Ronny again. But placing a base station close to the breeding site of the male showed us that it was 679, Ronny.
Three years after tagging, and the tracker was still doing fine! The first communication attempts showed us that the memory was indeed full and the battery doing well. After more observations in the field, we found that Ronny has a second female and adding an extra relay antenna allowed us to download all the data. Now we were very happy, three years of excellent tracking data of one individual, three winters, three times migration to Africa and back! He was wintering in Mali and breeding in Germany every year, but he never passed by Eastern Groningen again…
In the meanwhile, Ronny is collecting data like all other ‘normal’ birds and downloading on a regular basis thanks to an additional base station we could lent for this purpose. The nest of his first female is already protected and contains three chicks. The second nest will be protected next week.
This story about Ronny shows us how difficult it can be to find back birds tagged earlier in an area. Even though Montagu’s Harriers are very site-faithful, especially males, it can happen that birds move to other breeding areas and are just too far from the antenna systems to be found. Then, good fieldwork and a portion of luck is needed to retrieve the data!