Chestnut-sided Warbler (Crum Woods Biodiversity Guide)

Chestnut-sided Warbler

Setophaga pensylvanica

Summary ⁴

The Chestnut-sided Warbler (Setophaga pensylvanica) is a New World warbler. They breed in eastern North America and in southern Canada westwards to the Canadian Prairies. They also breed in the Great Lakes region and in the eastern USA.

Setophaga pensylvanica ⁵

A medium-sized (4 ½ -5 ½ inches) wood warbler, the male Chestnut-sided Warbler is most easily identified by its pale breast, streaked back, yellow crown, and conspicuous chestnut flanks. Female Chestnut-sided Warblers are similar to males, but are somewhat duller, especially on the flanks. No other wood warbler breeding in North America possesses the combination of chestnut flanks and yellow crown characteristic of this species. The Chestnut-sided Warbler primarily breeds across southern Canada and the northeastern United States. Smaller numbers breed at higher elevations in the Appalachian Mountains as far south as northern Georgia. In winter, the Chestnut-sided Warbler may be found in southern Mexico and Central America. Chestnut-sided Warblers breed in a variety of semi-open deciduous forests, particularly in areas of shrubby growth created by forest fires and other types of ecological disturbance. In winter, this species may be found in and around humid tropical forests. Chestnut-sided Warblers primarily eat small invertebrates, including insects and spiders, although this species may eat some plant material, particularly fruits and berries, during the winter. In appropriate habitat, Chestnut-sided Warblers may be observed foraging for insects underneath leaves in shrubs and lower parts of the canopy. Birdwatchers may also listen for this species’ song, a whistled “please please pleased to meet’cha.” Chestnut-sided Warblers are primarily active during the day, but, like many migratory songbirds, this species migrates at night.

Conservation status ⁶

Studies have been done on the effect of pesticides on the chestnut-sided warbler. They show that the birds still forage in treated areas, but return in fewer numbers in following years. It has been suggested that because the chestnut-sided warbler forages on the undersides of leaves, it may be less affected than other species in treated areas. It has been reported that a large number of chestnut-sided warblers are killed in collisions with stationary objects. Many are found dead at the base of TV towers, smokestacks, and large buildings during migration.

US Migratory Bird Act: protected

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Habitat ⁷

Before the 1800s, the chestnut-sided warbler was not well known. Because of its highly specialized habitat and foraging techniques, it was believed to be limited to former natural disaster areas such as sites of forest fires. With the clearing of primeval forests and the subsequent growth of shrubby habitats, the chestnut-sided warbler is one of the most abundant breeding warblers in second growth deciduous woodlands.

Terrestrial Biomes: forest

Iucn red list assessment ⁸

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) Mike H, some rights reserved (CC BY-NC), uploaded by Mike H
(c) Tom Benson, some rights reserved (CC BY-NC-ND), https://www.flickr.com/photos/40928097@N07/10414586653/
(c) Distant Hill Gardens, some rights reserved (CC BY-NC-ND), https://www.flickr.com/photos/59898141@N06/18076145639/
Adapted by Amanda Carrillo-Perez from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Setophaga_pensylvanica
(c) Smithsonian Institution, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34818211
(c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31390443
(c) The Regents of the University of Michigan and its licensors, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/31390436
(c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/34420016