Coexistence of protected avian predators: does a recovering population of White-tailed Eagle threaten to exclude other avian predators?

Abstract

The processes of competition and predation determine the degree to which species can coexist; the importance of competition in particular has been emphasized at high trophic levels. Competition exclusion will occur when habitat overlap between sympatric species is high. In this study, we investigated nesting habitat overlap between internationally protected diurnal tree-nesting avian predators of central Europe, namely, White-tailed Eagle (Haliaeetus albicilla), Lesser Spotted Eagle (Aquila pomarina), Black Stork (Ciconia nigra), and Osprey (Pandion haliaetus). We found significantly different nesting habitats among the study species and suggest that this could be a consequence of the resource-based segregation, but not a consequence of asymmetrical interspecific competition. The results also show that habitat of the recovering populations of White-tailed Eagle overlapped with the habitat used by the Lesser Spotted Eagle, Black Stork, and Osprey to varying extents with a niche overlap values being below the competition exclusion threshold. Nevertheless, we suggest that competition by White-tailed Eagle at a population level may limit Osprey, though not Lesser Spotted Eagle or Black Stork.

Intraguild predator drives forest edge avoidance of a mesopredator

“…Mesopredators need to adapt their avoidance strategies to the type, distribution, and density of different intraguild predators: habitat segregation and large scale avoidance is only possible if there are gaps in the distribution of the top predator, or if the mesopredator can resort to a habitat which is not used by the predator (Treinys et al. , Swanson et al. ).…”

Exotic lagomorph may influence eagle abundances and breeding spatial aggregations: a field study and meta-analysis on the nearest neighbor distance

“…However, being larger in size, the eagles may be at a competitive advantage, ultimately limiting the abundance of the smaller hawk species. The lower abundance of other raptors where BCB eagle abundance is high could be influenced by intraguild predation ( Sergio & Hiraldo, 2008 ; Treinys et al, 2011 ). In fact, there is evidence of predation of some of these species (e.g., M. chimango , F. sparverius ) by the BCB eagles ( Hiraldo et al, 1995 ) and also frequent agonistic interactions with other raptors (mostly with G. polyosoma ; Jiménez & Jaksić, 1989 ).…”

Roles of Raptors in a Changing World: From Flagships to Providers of Key Ecosystem Services

“…Besides, diffuse competition (Bock et al, 1992;Piana and Stuart, 2012), a scarcely-studied process, competitive exclusion may determine that most aggressive and/or social species can displace other birds of prey from preferred breeding areas (Krüger, 2002; although high variability can be expected depending on site-specific contexts (see e.g. Treynis et al, 2011). Also, when a group of species exploits simultaneously the same food resource, as happens with avian scavengers, monopolisation by dominants (e.g., Eurasian griffon vultures) may appear when their relative abundance increases (Donázar et al, 2010; see also , and negative effects on populations of the subordinate avian scavenger species, as well as on other organisms, are predicted (De Vault et al, 2003;Shivik, 2006;Selva and Cortés-Avizanda, 2009;Cortés-Avizanda et al, 2012).…”