Age mediates access to landfill food resources and foraging proficiency in a long-lived bird species

Martins, Bruno Herlander, Soriano-Redondo, Andrea, Franco, Aldina M. A. ORCID: and Catry, Inês (2024) Age mediates access to landfill food resources and foraging proficiency in a long-lived bird species. Animal Behaviour, 207. pp. 23-36. ISSN 0003-3472

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Human activities have altered the availability of resources for wildlife. Landfill sites now provide abundant and predictable anthropogenic food subsidies worldwide, sustaining increasing numbers of opportunistic species and shaping their foraging behaviour. However, although individuals may differ in their ability to use these resources, the factors influencing this variability within species are still poorly known. Using GPS data from 68 adult and 67 juvenile white storks, Ciconia ciconia, tracked during their premigratory periods between 2018 and 2020, we investigated whether age determines landfill attendance and the ability to compete for space and food. Additionally, using video recordings of 165 adults and 124 juveniles obtained in the 2020 premigratory period, we investigated whether age influences landfill foraging proficiency and dominance over resources. Adult storks visited landfills on 57% of the days, while juveniles only visited landfills on 29% of the days. There was strong competition for food at landfills, with adults exerting dominance over juveniles, foraging predominantly in areas with higher food availability and outcompeting juveniles in food acquisition. Juveniles had significantly lower food intake rates in the best foraging areas and showed less aggressiveness, being forced to use adjacent lower quality areas. Overall, juveniles had limited access to landfill resources, suggesting that landfill diet specialization is mediated by age-related improvements in foraging expertise and increased competitiveness developed during maturation. Thus, landfill use is shaping foraging strategies and species behaviour from an early age, with potential consequences for population dynamics.

Item Type: Article
Additional Information: Data Availability: The tracking data used in this study are stored in Movebank (, study names ‘White Stork Adults and Juveniles 2016’, ‘White Stork Adults 2017’, ‘White Stork Juveniles 2017’, ‘White Stork Adults 2018’, ‘White Stork Juveniles 2018’, ‘White Stork Adults 2019’, ‘White Stork Juveniles 2019’, ‘White Stork Adults 2020’, ‘White Stork Juveniles 2020’) and will be available in the Movebank Data Repository ( after a 1 year embargo, or on request. Behavioural data obtained through video recordings are available as Supplementary Material. Funding information: This work was supported by the European Regional Development Fund (FEDER) through the Operational Competitiveness Factors Program (COMPETE) and by National Funds through the Foundation for Science and Technology (FCT) within the scope of the project Birds On The Move (POCI-01-0145-FEDER-028176), by InBIO (UID/BIA/50027/2013 and POCI-01-0145-FEDER-006821), and by the Natural Environment Research Council (NERC) via the EnvEast DTP, and NERC and Engineering and Physical Sciences Research Council (EPSRC) via the NEXUSS CDT Training in the Smart and Autonomous Observation of the Environment. Funding for the development of the GPS tracking devices was provided by NERC (NE/K006312), Norwich Research Park Translational Fund, University of East Anglia Innovation Funds and Earth and Life Systems Alliance funds. B.H.M. was supported by a doctoral grant (SFRH/BD/145323/2019) and I.C. by a contract (2021.03224.CEECIND) from FCT.
Faculty \ School: Faculty of Science > School of Environmental Sciences
University of East Anglia Research Groups/Centres > Theme - ClimateUEA
UEA Research Groups: Faculty of Science > Research Centres > Centre for Ecology, Evolution and Conservation
Faculty of Science > Research Groups > Environmental Biology
Depositing User: LivePure Connector
Date Deposited: 15 Nov 2023 11:55
Last Modified: 15 Nov 2023 11:55
DOI: 10.1016/j.anbehav.2023.10.011


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