We also suggest a novel hypothesis for the success of warblers today in the Caribbean and other habitats, beginning with their relatively recent adaptive radiation and the ecological opportunity on Caribbean islands. Our review and synthesis of interspecific competition and coexistence in warblers have important consequences, including our questioning of the importance and effectiveness of resource partitioning in birds. We argue that an important, underappreciated, mechanism of competition among coexisting migratory warbler species, particularly in winter, is diffuse exploitation competition, based in part on our own studies of warbler diets in relation to foraging behavior, substrate use, bird morphology, and other traits. To understand what MacArthur got right and what he missed, we reviewed both ecological and evolutionary approaches to questions of the origin and coexistence of competing species in the context of diet. MacArthur coined the phrase “resource partitioning”, and profoundly impacted the field of Ecology for subsequent decades in diverse ways. We focus on New World wood warblers (Parulidae), beginning with Robert MacArthur’s iconic 1958 paper in which he shows how subtle foraging behaviors, purportedly linked to dietary differences, within spruce trees contribute to the coexistence of 5 spruce-woods warbler species. Warblers' insectivorous diets make them economically important to humans, especially species that help to control spruce budworm.The extent to which interspecific competition structures species interactions and coexistence within communities, and the relevant mechanisms, are still debated. petechia) of building new nests on top of old.ĭeclines in several warbler species have prompted a marked increase in research on migratory bird species on their wintering areas in South and Central America. Several species have evolved mechanisms which reduce cowbird parasitism, eg, the well-known habit of the yellow warbler ( D. The brown-headed cowbird ( Molothrus ater), a significant brood parasite of several species, poses a significant threat to the rare Kirtland's warbler ( Dendroica kirtlandii). Flycatchers usually have flatter bills with bristles at the base.Įxceptions to the usual cup-shaped nests in shrubs and forks of trees include the dome-shaped ground nest of the ovenbird ( Seiurus aurocapillus) the hanging, lichen-based nest of the northern parula ( Parula americana) and the hole nest of the prothonotary warbler ( Protonotaria citrea), the only species that uses artificial nest boxes. Their sharp, pointed bills are ideal for probing for insect prey, though some species also catch insects by aerial pursuit. In spring males are usually brightly coloured females have duller plumages, as do males in fall. Many warblers have bright yellow plumage which gives them the colloquial name wild canary, a term also applied to American goldfinches ( Carduelis tristis). More restricted breeders include several Dendroica species: Louisiana waterthrush ( Seiurus motacilla) and prothonotary, hooded warblers ( Wilsonia citrina) and probably Kentucky warblers ( Oporornis formosis), both of southern Ontario, northern parula of southern Manitoba east through the Maritimes, yellow-breasted chat ( Icteria virens) of southern Ontario and local valleys of southern BC, Alberta and Saskatchewan.
![new world warblers new world warblers](https://www.gschneiderphoto.com/gallery3/var/albums/birds/warblers/prothonotary-warbler/prothonotary-warbler-water_7606.jpg)
![new world warblers new world warblers](http://www.nhptv.org/wild/images/SpectacledRedstart.jpg)
The creeperlike black-and-white warbler ( Mniotilta varia), the black-masked, marsh-dwelling common yellowthroat ( Geothlypis trichas), the flycatching American redstart ( Setophaga ruticilla), the thrushlike, ground-dwelling ovenbird, the northern waterthrush ( Seiurus noveboracensis) and 2 species of Wilsonia are also widespread. Two other widespread genera of several species are Vermivora and Oporornis, the latter known as "skulkers" of low brush. Kirtland's warbler, until recently thought to breed only in a restricted area of Michigan, is now believed to have nested in Ontario and possibly Québec. Most Canadian breeding species belong to genus Dendroica. They are widespread, breeding virtually everywhere south of the treeline and forming spectacular mixed-species flocks during migration, especially in the East. Warbler is a name applied to several groups of birds, primarily the New World wood warblers (family Parulidae), and Old World warblers (Sylviidae) of which only 3 species commonly breed in Canada ( see kinglet).Ībout 37 of the 115 species of wood warbler nest in Canada.