Royal Netherlands Institute for Sea Research
Royal Netherlands
Institute for Sea Research

Seabird diets and population dynamics

The North Sea is extensively used for its fish supply and offshore energy sources. At the same time, the North Sea has significant ecological values. Seabirds are sensitive to changes in food supplies and can be used to monitor the marine environment. At NIOZ we study diet and demography of Herring Gulls (Larus argentatus) and Lesser Black-backed Gulls (Larus fuscus). Within these generalist gulls, individuals are more or less specialised in what they eat. One of the main aims of this project is to unravel the consequences of having a specialised diet on reproductive success, and how these specialised individuals adapt to changes in North Sea habitat suitability due to windfarm construction, and changes in food supplies due to changes in fish stocks and the ban on discards. 

During the breeding period between April and August we collect data on reproduction and offspring growth rates in the breeding colony at Texel, and collect information on individual diets. We catch and colour ring gulls, and work with GPS tagged birds as well. We sort out diet samples in the lab and analyse food remains to the level of individual prey items, and analyse feather and blood samples of individual gulls for stable isotope signatures.

Research project

Within the scope of ongoing research, various research questions can be thought of. Examples are: ‘Do chick diets overlap with that of their parents?’ ‘Does chick growth and survival depend on diet?’ ‘Are diets repeatable within-year and between-year?’ We will discuss particular interests with the students at the start of the project.


Starting April 2020. Intake interview will be some time before the starting date.

Extra information

We are looking for a motivated bachelor or master student who has great affinity with fieldwork and data analysis. This is a project for at least six months. You must be prepared to work in some weekends as well. See for more information:

Daily supervisors

Rosemarie Kentie:, and Kees Camphuysen: