Bay-breasted Warbler (Crum Woods Biodiversity Guide)

Bay-breasted Warbler

Setophaga castanea

Summary ⁴

The Bay-breasted Warbler (Setophaga castanea) is a New World warbler. They breed in northern North America, specifically in Canada, into the Great Lakes region, and into northern New England.

Taxonomy ⁵

Comments: Phylogenetic analyses of sequences of mitochondrial and nuclear DNA (Lovette et al. 2010) indicate that all species formerly placed in Dendroica, one species formerly placed in Wilsonia (citrina), and two species formerly placed in Parula (americana and pitiayumi) form a clade with the single species traditionally placed in Setophaga (ruticilla). The generic name Setophaga has priority for this clade (AOU 2011).

Habitat ⁶

During the summer breeding season, the Bay-breasted Warbler (Setophaga castanea) fills a particular ecological niche of being an insectivorous foliage gleaner in northern forests (Cornell 2015) - foraging among interior branches in the middle of conifers. As a result, the bird is known as a characteristic bird of forests of this type. The Bay-breasted Warbler prefers thick spruce and fir stands in northern coniferous forests, but will nest in deciduous or mixed second-growth forests of birches, maples, firs, and pines, typically due to boons in the population of spruce budworm (Audubon 2014). Within northern spruce and fir forests, this species prefers small forest openings and the edges of clearings, bogs, and ponds. In New England, Bay-breasted Warblers prefer second-growth boreal forests six to ten feet tall; in New Hampshire the bird has been found nesting at elevations of up to four thousand feet in coniferous or mixed forest. For nesting habitat, Bay-breasted Warblers prefer the thick lower branches of full, mature conifers (Kelly n.d.), and place nests on a horizontal branch of a dense spruce, hemlock, birch, or other similar trees. Nests are made four to forty feet above the ground (Audubon 2014).

The Bay-breasted Warbler migrates long distances from its summer breeding grounds in eastern Canada and the northeastern United States to its wintering grounds in tropical Central and northern South America. This species is specifically found in lowland tropical and second-growth forests (Cornell 2015). In these tropical and second-growth areas, the Bay-breasted Warbler prefers forest edge and open woodland habitats (Audubon 2014). During the wintering months, the diet of the Bay-breasted Warbler includes more fruit. In both seasons, the species is generally absent from landscapes affected by clearcutting, agriculture, and development causing habitat fragmentation. In fact, in Quebec, Bay-breasted Warblers were not found in forests with less than 55% mature cover (USDA 2015).

Iucn red list assessment ⁷

Red List Category

Least Concern

Red List Criteria

Version

3.1

Year Assessed

2012

Assessor/s

BirdLife International

Reviewer/s

Butchart, S. & Symes, A.

Contributor/s

Justification

This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is extremely large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

History

Least Concern (LC)
Least Concern (LC)
Least Concern (LC)
Lower Risk/least concern (LR/lc)
Lower Risk/least concern (LR/lc)
Lower Risk/least concern (LR/lc)

Sources and Credits

(c) Carmelo López Abad, some rights reserved (CC BY-NC), uploaded by Carmelo López Abad
(c) Mdf, some rights reserved (CC BY-SA), https://upload.wikimedia.org/wikipedia/commons/thumb/a/af/Dendroica-castanea-001.jpg/460px-Dendroica-castanea-001.jpg
Wikimedia Commons, no known copyright restrictions (public domain), https://upload.wikimedia.org/wikipedia/commons/3/33/BaybreastedWarbler23.jpg
Adapted by Amanda Carrillo-Perez from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Setophaga_castanea
(c) NatureServe, some rights reserved (CC BY-NC), http://eol.org/data_objects/28864813
(c) Taylor Clark, Editors: Anneke DeLuycker, Jim McNeil, Marcy Heacker, some rights reserved (CC BY-NC), http://eol.org/data_objects/33094075
(c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34419944