Habitat choice in Phylloscopus warblers: the role of morphology, phylogeny and competition

Abstract

We studied ecological and evolutionary aspects of habitat choice in a group of closely related bird species to gain insight into factors influencing bird community structure. Seven species of Phylloscopus warblers breed sympatrically in the middle taiga subzone of Central Siberia. We examine how the distribution of species among habitats is related to morphology, phylogeny and competition, and we compare our results with an earlier study on the ecomorphology of Phylloscopus warblers in Kashmir. We found that in Siberia, large warbler species prefer productive habitats with mostly deciduous vegetation, whereas small species occupy poor coniferous forests. Possible explanations for this finding remain to be tested in the future. Moreover, we found a tendency for species with large feet, small bills and short wings to occupy habitats with an abundance of bush thickets near the ground. In the Kashmir study, competition was considered a major factor in structuring the Phylloscopus community, and patterns of habitat choice were not influenced by phylogenetic relationships. In strong contrast, we found that in the Siberian community, closely related species occupy similar habitats. We discuss whether this conservative evolution of habitat preferences in Siberia may be due to low intensity of interspecific competition or to other ecological factors.

Morphological convergence in conifer-dwelling passerines

“…In line with our study, coniferous species tend to be smaller than deciduous species among the Phylloscopus warblers (Gaston 1974;Forstmeier et al 2001). The latter authors developed three hypotheses to explain such a relationship: (1) Small species may show a preference for coniferous habitats because small body size allows more efficient use of foraging techniques that are advantageous in coniferous vegetation, such as hovering flight and clinging to conifer-needles, (2) larger species may prefer habitats with on average larger prey items, which are found in deciduous trees (Nystro¨m 1991), and (3) smaller species might profit from the reduced interspecific competition in a coniferous habitat (Forstmeier et al 2001).…”

“…Within 16 Dendroica warblers of North America, the coniferous forest breeders are generally larger than deciduous forest breeders (Greenberg 1979). In contrast, among the Old World Phylloscopus warblers, the conifer-dwelling species have significantly lower body masses than the deciduous inhabitants (Gaston 1974;Forstmeier et al 2001).…”

“…The latter authors developed three hypotheses to explain such a relationship: (1) Small species may show a preference for coniferous habitats because small body size allows more efficient use of foraging techniques that are advantageous in coniferous vegetation, such as hovering flight and clinging to conifer-needles, (2) larger species may prefer habitats with on average larger prey items, which are found in deciduous trees (Nystro¨m 1991), and (3) smaller species might profit from the reduced interspecific competition in a coniferous habitat (Forstmeier et al 2001). For our study, we favour the first hypothesis, since our ''needle-dwellers'' prefer foraging sites that are high off the ground, and clinging to thin substrates and hovering flight are preferred locomotion types at such high foraging sites (Morse 1976;Greenberg 1979;Perrins 1979).…”

Wing size-related reed habitat selection by Great Reed Warbler (Acrocephalus arundinaceus) males

“…Wing length was found to be associated with migration distances in long-distant migratory birds (Tarka et al 2010), which may indicate its importance in flight ability and survival. Wing size is also a signal for dominance among males in reed passerines (Nowakowski 2000, Forstmeier et al 2001, which can thus be used as a correlate of the quality of the breeding habitats (Johnson 2007). Furthermore, Alatalo et al (1985) and Rayner (1988) suggested that habitat structure can have selective effects on wing sizes at microevolu-tionary time scales.…”

Effects of landscape, conspecifics and heterospecifics on habitat selection by breeding farmland birds: the case of the Calandra Lark (Melanocorypha calandra) and Corn Bunting (Emberiza calandra)

“…The constraints that limit or prevent individuals from occupying those habitats where they could achieve greater fitness may be classed as evolutionary or ecological. Evolutionary constraints include all those that weight heavily on the biology of a species, such as its phylogeny or its life history traits (Forstmeier et al 2001). Ecological constraints include those arising from the landscape and biotic environment in which the species occurs.…”