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<p>In territorial raptors, breeding performance and foraging behaviour are affected by territory characteristics as the abundance and availability of different prey species varies between habitats. In this study, we examined the diet of two White-tailed Eagle pairs, occupying neighbouring territories in two adjacent inland lakes in Northern Greece. We assess the diet composition of the species in the southernmost part of its European range and evaluate any intraspecific differences in the diet that may reflect resource and/or niche partitioning between territories. We found that birds and specifically waterbirds comprise the largest and quantitatively most important part of the White-tailed Eagle´s diet, with fish being the second most important prey group that was only found in the nest remains from one territory. There was high diet overlap between the two territories and when considering only avian prey our results suggest that the species predates on heavier (and the most common) waterbird species. A main factor that could be driving differences in the abundance and availability of different prey species between territories could be lake physiography, as our results point to a segregation and a subsequent resource partitioning between territories, with each pair utilizing an adjacent lake and its associated habitats. Competition and territoriality therefore seem to be important intraspecific interactions that along with prey availability could promote changes in territory size and ultimately affect individual fitness.</p>
</abstract>

In territorial raptors, breeding performance and foraging behaviour are affected by territory characteristics as the abundance and availability of different prey species varies between habitats. In this study, we examined the diet of two White-tailed Eagle pairs, occupying neighbouring territories in two adjacent inland lakes in Northern Greece. We assess the diet composition of the species in the southernmost part of its European range and evaluate any intraspecific differences in the diet that may reflect resource and/or niche partitioning between territories. We found that birds and specifically waterbirds comprise the largest and quantitatively most important part of the White-tailed Eagle´s diet, with fish being the second most important prey group that was only found in the nest remains from one territory. There was high diet overlap between the two territories and when considering only avian prey our results suggest that the species predates on heavier (and the most common) waterbird species. A main factor that could be driving differences in the abundance and availability of different prey species between territories could be lake physiography, as our results point to a segregation and a subsequent resource partitioning between territories, with each pair utilizing an adjacent lake and its associated habitats. Competition and territoriality therefore seem to be important intraspecific interactions that along with prey availability could promote changes in territory size and ultimately affect individual fitness.

Diet composition of White-tailed Eagles inhabiting two adjacent inland lakes in Northern Greece

Department of Biological Applications and Technology

Raptor Journal

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

In territorial raptors, breeding performance and foraging behaviour are affected by territory characteristics as the abundance and availability of different...

Diet composition of White-tailed Eagles inhabiting two adjacent inland lakes in Northern Greece

Published Online: Jun 11, 2023

Page range: 15 - 24

Received: Dec 10, 2022

Accepted: Mar 02, 2023

DOI: https://doi.org/10.2478/srj-2023-0002

Keywords
intraspecific competition, foraging ecology, niche partitioning, prey remains

© 2023 Anastasios Bounas et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Diet composition of White-tailed Eagles inhabiting two adjacent inland lakes in Northern Greece

Published Online: Jun 11, 2023

Page range: 15 - 24

Received: Dec 10, 2022

Accepted: Mar 02, 2023

DOI: https://doi.org/10.2478/srj-2023-0002

Keywordsintraspecific competition, foraging ecology, niche partitioning, prey remains

© 2023 Anastasios Bounas et al., published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Keywords
intraspecific competition, foraging ecology, niche partitioning, prey remains