One week after we fitted 9 juvenile Lesser Black-backed Gulls with GPS loggers as part of our Dutch IJmuiden Forteiland project, I am happy to report that they are doing well.
All are in good condition and are responding well to carrying the device on their back. They are also growing fast, doing flight exercises and some of them are even flying in or around the island.
At the time of writing (17 July 2019), one juvenile has even made a short and brief trip to a nearby beach: our first juvenile that has properly left the island! It won’t be long before all of them will start leaving the colony.
Below is an overview of each individual. Click the images for a larger view.
(When available, data from the loggers can be viewed on uva-bits.nl.)
YCWF – logger #5946
YCWF is staying close to the territory where it is being cared for by its colour-ringed father YCCM and mother YBKW.
Mother YBKW is also fitted with a GPS logger (#5861) and based on the GPS-tracks she is providing a varied diet by fouraging in urban areas (Hoofddorp and Amsterdam) and out on the North Sea.
YCWT – logger #5797
YCWU – logger #5951
These two siblings are part of a family of which another sibling is colour-ringed (YCWV) but which does not have a GPS logger fitted. Their mother is unringed but their father is colour-ringed (YBJC) and is also fitted with a GPS logger (#5491).
Above: father YBJC with all 3 ringed juveniles.
They are a close family and the siblings can frequently been seen in the territory with one of their parents, although all three of them have already been exploring the edge of the island as is clear from the GPS data above.
Father YBJC is quite famous because he has been visiting a particular location in Amsterdam very frequently for years. Now fitted with a GPS logger, we can see that regular trips out to the North Sea are also made, very likely to provide the juveniles with high-energy food.
YCXJ – logger #5952
I photographed YCXJ on 15 July while it was flying fast past the island…
Its track can actually be seen on the GPS data of that day; it’s one of the points on the north side:
We have no details on the parents yet.
YCZN – logger #5942
YCZN is staying close to its territory for now. We have yet to find out details about its parents.
YCZP – logger #5943
YCZP is also staying close to its territory for now. We don’t know yet who its parents are.
YCZR – logger #5944
YCZR is the most adventurous and is the first to have properly left the island. On 16 and 17 July it made a short flight to the nearby beach at Wijk aan Zee!
YCZS – logger #5950
YCZS has seen many parts of the colony already. We don’t have any details of its parents yet.
YCZT – logger #5953
Since YCZT was ringed and fitted with the logger, we have found out that YCAR is its mother. This is great news because we know that she winters in Gijon, Spain. One of our research questions is how juveniles find their wintering location so it will be interesting to see if it perhaps follows YCAR to Spain.
The GPS data shows that it has already been visiting the western part of the colony (ignore the data points to the south, these are caused by interference).