Earlier this year, an app was released in the Netherlands with which birds fitted with a GPS logger can be followed. This is done by viewing various tracks that are made available by the team of researchers that are behind this project.
Specific locations that these birds visit and of which the researchers want to know why they are visited by these birds are indicated and accompanied by a list of specific questions. The app can be used to visit these locations, answer the questions and upload photos: citizen science at work!.
Last Sunday I went to one of the locations that was visited by European Herring Gull Larus argentatus argenteus ringed as Green M.ANK.
It was fitted with a GPS device in May 2013 and my first and only observation was in June 2014 when I observed him at his marked nest in the gull colony of Texel, the Netherlands. He was last observed there by researchers in July.
The location that the researchers were interested in finding out more about was an industrial estate in the small city of Waddinxveen, located to the south-east of The Hague.
It was visited by MANK in March when it came over from the gull colony at Texel in the north of Holland (a distance of some 100kms), stayed the night and returned to the gull colony the next day.
What attracted M.ANK to visit that site and stay the night? That’s for us citizen scientists to find out.
I visited the location initially on Sunday 24 August and did not come across anything out of the ordinary that would attract the attention of gulls such as obvious signs of waste disposal.
While I was there though I actually saw an adult Herring Gull that was fitted with a color ring sitting on top of a lamp post. Unfortunately it flew off before I was able to read the ring or check if it was fitted with a GPS device. It would be too much of a coincidence though if this would not have been Green M.ANK, but of course I could not be sure.
So I went back on Monday 25 August on the off chance that I would be able to relocate M.ANK.
After driving around the industrial estate I did not come across many gulls but after a few minutes I saw an adult Herring Gull fouraging on earthworms in a grassy field. I checked for the presence of a ring and it indeed turned out to be Green M.ANK!
I was able to observe him for about an hour during which he sat on top of various lamp posts and was clearly interested in the grassy field. He even chased off another adult Herring Gull as well as an adult Lesser Black-backed Gull as if to make clear that they were not welcome there.
He gave me the impression that he was well at ease at that location and that he possibly had been there for quite a while (maybe he uses it as his wintering location?).
However, checking the Web site of the UVA Bird Tracking System and filtering the near-live map on the GPS device of M.ANK (number 6015, yellow track) shows that he has been making trips between Texel and Amsterdam city center as recently as mid-August. But maybe he has since re-located to Waddinxveen.
Exactly what attracts him there is still a bit of a mystery. Maybe he stumbled upon this location by accident and is able to find whatever he needs (food, water and a place to rest) in and around the area.
I did notice though that the industrial estate was fairly quiet with few people walking around during their lunch break and that there is little chance therefore of the gulls being disturbed. Perhaps this is what attracts him over similar sites in neighbouring cities.
All in all this was a very successful day which went far beyond our expectations: I had never expected to find M.ANK let alone observe him so well, especially knowing that has has been visiting other locations as recent as 2 weeks previous.
I might check up on him later this year to see if he is spending the winter at that location (I am awaiting confirmation from the researchers to find out if M.ANK spent last winter in Waddinxveen as well).
Incidentally: the latest GPS data won’t be downloaded until the beginning of next year’s breeding season so we will have to wait to find out how long he has been there and where else he has been or will go to.
For more information about this project, visit the Web site of ‘Vogel het Uit’.
See also this article about his visits to Amsterdam (in Dutch): Wat doet meeuw 6015 (MANK) toch in Amsterdam?