Foraging for high caloric anthropogenic prey is energetically costly

Susanne Van Donk*, Judy Shamoun-Baranes, Jaap Van Der Meer, Kees C.J. Camphuysen

*Corresponding author for this work

    Research output: Contribution to JournalArticleAcademicpeer-review


    Background: Several generalist species benefit from food provided by human activities. Food from anthropogenic sources is often high in caloric value and can positively influence reproductive success or survival. However, this type of resource may require specific foraging skills and habitat experience with related costs and benefits. As a result, not all individuals utilize these resources equally, with some individuals preferentially foraging in habitats where natural resources of lower energy content are predominant, possibly due to lower energy expenditure of the specific foraging strategy. Methods: Here we investigate whether foraging in habitats which contain high caloric resources of anthropogenic origin is energetically costlier than foraging in habitats with low caloric resources such as intertidal areas or agricultural and natural areas, for example due to increased flight costs, in a generalist seabird, the herring gull Larus argentatus. We use data from GPS trackers with tri-Axial acceleration measurements that allow us to quantify time-energy budgets, representing energy expenditure during foraging trips of herring gulls for each habitat. Results: We show that the rate of energy expenditure is on average 34% higher when individuals forage for high caloric prey in marine and urban areas compared to foraging for low caloric prey in intertidal and agricultural areas. Energetic estimates suggest that if birds would feed completely on these resources, they have to gather ~ 400 kJ per day more to compensate for the higher foraging costs. Conclusions: Energy expenditure differs among foraging habitat and may thereby influence foraging decisions of individual herring gulls. As management of anthropogenic resources changes, so too may the costs and potential benefits of foraging strategies which are strongly tied to human activities.

    Original languageEnglish
    Article number17
    JournalMovement Ecology
    Publication statusPublished - 24 May 2019


    These studies are part of a long-term demographical and ecological study on sympatric breeding gulls by the Royal Netherlands Institute for Sea Research (NIOZ) at Texel. We thank Staatsbosbeheer Texel for permission to work in Kelderhuispolder, a nature reserve closed for the general public. Particularly, we thank Aris Ellen, Glenn van Ginkel, Marcel Groenendaal, and Erik van der Spek for help and cooperation. We thank Willem Bouten for his advice, Edwin Baaij for his technical support of UvA-BiTS and Jan Baert for helping with analytical problems. We thank all the volunteers that helped in catching the gulls and other fieldwork over the years. The UvA-BiTS infrastructure was facilitated by Infrastructures for E-Science, developed with the support of the Netherlands eScience Centre (NLeSC) and LifeWatch, and conducted on the Dutch National E-Infrastructure with support from the SURF Foundation. We thank two anonymous reviewers for their helpful comments.

    FundersFunder number
    Surfrider Foundation
    Netherlands eScience Center
    LifeWatch – Niclas Öberg Foundation


      • Anthropogenic impact
      • Energy expenditure
      • Foraging strategies
      • Larus argentatus
      • Movement


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