In 2006, a project was started by the Royal Netherlands Institute for Sea Research (NIOZ) to study the foraging ecology and breeding biology of European Herring Gulls Larus argentatus and Lesser Black-backed Gulls Larus fuscus in a mixed gull colony on the Dutch island of Texel.
Led by researcher Kees Camphuysen, a broad range of aspects of the life inside and outside a breeding colony were recorded.
Now, 6 years later, Kees has brought the data together for the first time in a thesis named “A historical ecology of two closely related gull species (Laridae): multiple adaptations to a man-made environment.”
A PDF version of it can be downloaded on the Web site of the University of Groningen (15,1 MB, 421 pages).
If you have an interest in gulls, I highly recommend you to read this.
Some of the topics that you will see discussed include:
- The preferences in diet and foraging locations of the two species.
- The changes in diet during the various phases of the breeding season.
- Breeding success and longevity records.
- Chick mortality (or: why do chicks mostly die on a Sunday?)
- Cannibalism (one species attacking the chicks of another).
- Dispersal and migration.
- Dutch color ring projects.
- And much, much more.
Part of the Lesser Black-backed Gull data is based on GPS devices that were fitted on several individuals. It has resulted in a fascinating insight into the whereabouts of these individuals throughout the year. Be prepared for some incredible revealings.
In the section dealing with longevity, data is used from the late 1980’s when Herring Gull chicks were ringed in 12 Dutch colonies for a period of 3 years. The longest known survivor of these projects is a Herring Gull ringed as a juvenile in 1986 — a gull which I have been actively following since 2009. My most recent observation dates from May 25, 2013 when it was in its 28th calendar year. It is the oldest known ringed Dutch Herring Gull.
As a ring reader, it’s nice to have made a tiny contribution to research projects and publications such as these.
I also feel fortunate to have been invited by Kees to visit his gull colony on Texel, to see him at work and to assist him (on a very small scale) in his research. My yearly visits since 2010 have given me an enormous respect for his dedication and love of gulls and I am thankful that he has allowed me access to the fascinating lives that gulls lead and thereby widening my view on gulls.
This week Kees will be receiving his doctorate at the University of Groningen based on this thesis, a ceremony that I am very much looking forward to attend.