On 8 July 2019, 9 juvenile Lesser Black-backed Gulls from the IJmuiden Forteiland colony in the Netherlands were fitted with a GPS-logger. This is in addition to the 10 loggers that were fitted to adult Lesser Black-backed Gulls earlier in May.
This was done in cooperation with the University of Amsterdam (UvA, who provide the techology) and the Royal Netherlands Institute for Sea Research NIOZ (who manages our colour ring project since its start in 2008).
Above: Juvenile Lesser Black-backed Gull Green YCZR with logger #5944.
Above: Tracks of juvenile Lesser Black-backed Gulls in their territory. (Click for a larger view)
The aim is to learn more about the daily movements and the fouraging and flight behaviour of these juveniles and how this differs from adults / their parents. Another important aspect of this project is to learn more about the migration of juveniles in relation to adults / their parents. How do they learn where to spend the winter: by following their parents or just any adult?
To facilitate this, 2 of the juveniles belong to a family of which the father is also fitted with a GPS logger, while 1 juvenile belongs to a different family of which the mother is fitted with a GPS logger (and their father is colour-ringed). It will be very interesting to see if and for how long the juveniles will stick together with their parents over the coming months. Of course, it could still be that they follow the parent which is not fitted with a GPS logger, out of our view.
To my knowledge, this is the first time that GPS loggers have been fitted to juveniles of large gull species. This is partly because of the challenge of fitting the device on a not yet fully grown bird, and also because of the risk of losing the devices because of the high mortality rate that generally exists in young gulls.
Because of this mortality rate, the devices are also equipped with a GSM-function that allows sending (limited) data via satellite. This way at least some data can be gathered even when the device is out of reach of the regular receiving equipment.
Follow the gulls online
The last 3 days of available GPS (not GSM) data) can be viewed on uva-bits.nl as long as this data is available. The page also provides more information about the project.
Submit your observations
While we can obviously track our gulls remotely via the loggers, we are still very interested in any sightings at any time. We would especially like to know about the condition of the logger, behaviour of the gull (eating, resting, preening, and so on), and details about the location and conditions.
Should you come across one of our gulls therefore, please submit your sighting (with photos if you have them) to Kees Camphuysen: kees.camphuysen (at) nioz.nl. Feel free to CC me on it as wel: gulls (at) vankleinwee.com.