Bird Finder for June 30: Chestnut-Sided Warbler

Chestnut-sided Warbler
Setophaga pensylvanica

The Connecticut Audubon Society is working on habitat restoration and management projects that will benefit chestnut-sided warblers in all four corners of the state. This week’s post is by a longtime member of our Board of Directors.

by Mike Aurelia
The male chestnut-sided warbler is one of Connecticut’s most colorful warblers. These warblers are found in older fields that are going through successional changes as shrubs and saplings multiply, and on the edges of deciduous forests. This common Setophaga warbler can deal with both wet and dry habitats.

What it looks like: According to Cornell’s Online “The Birds of North America” the breeding male has a bright yellow cap with extensive chestnut coloring on its flanks. Its back has yellow and black stripes as well as solid black markings on its face. The female is drabber, with a greenish yellow cap, less black on the face, and chestnut only on the upper sides of the breast. Non-breeding males and females are similar, with a greenish yellow crown and back with less chestnut on the flanks.

Where and How to Find It: This time of the year, chestnut-sided warblers are found in good nesting habitat. Although old field and scrubby habitat can be found all over Connecticut, that type of habitat is declining as forests mature, and fields get developed and converted to lawns.

There is a distinct concentration of breeding birds in the northwest corner of the state. To zero in on where the nearest chestnut-sided warbler has been recently seen go to eBird.org. Click Explore Data Species maps function and insert Chestnut-sided warbler. For species date, chose year round current year. For location, Connecticut, and click on any orange or blue hotspot “drop.”

So far this year chestnut-sideds have been observed at a hundred or more locations around the state including the Connecticut Audubon Society’s Birdcraft, Larsen, and Bafflin sanctuaries.

Other interesting facts: Like many warblers chestnut-sideds are almost wholly insectivorous and focused on the larva and adults of butterflies and other flies, though in a pinch they can tackle some fruit.

Nesting occurs within six feet of the ground in woody shrubs. The female builds a small nest while the male watches. Though the male doesn’t help with the brooding he does help with defense and feeding of the young. A typical nest holds four eggs, usually a ground or creamy white in color and spotted, and the eggs usually hatch in 11 to 12 days.

In the fall these birds migrate to Central America and the northern most tip of South America.

Conservation Status: The chestnut-sided warbler is currently rated as a species of least concern. This is due to the fact that the species can quickly adapt to changes or significant openings in deciduous forests where shrubby habitats can develop within a few years.

Cutting for trees and allowing fields to pass through succession all result in creating more habitats for this warbler. The chestnut-sided warbler therefore benefits from all the work being done by Connecticut Audubon, the Natural Resources Conservation Service and the Connecticut Department of Energy and Environmental Protection to restore woodcock and New England cottontail habitat.

Photo by Rick Harris, Carolinabirds.org