The Wood Thrush, a relative of the familiar American Robin, is often considered a symbol of the population declines of birds that nest in North America and winter in the tropics. This species has been declining since the mid-1960s, and is on the National Audubon Society’s 2007 WatchList of declining birds.
Wood Thrushes nest in forests over much of the eastern U.S. Like most other songbirds, they migrate at night. These thrushes travel an average of 2200 km between their nesting areas and wintering grounds in Central America.
In the winter, Wood Thrushes are most common in primary and mature second growth forests, and they can be a familiar site on polyculture shade coffee farms from Mexico to Panama. For instance, they are the most commonly banded species at the gorgeous shade farm Finca Esperanza Verde in Nicaragua — we caught and saw a number of them when we were there in March 2009.
One reason for Wood Thrush declines may be tropical deforestation. At least one study has found a correlation between reduced numbers of Wood Thrushes and reduction in forest cover in the northern portion of their wintering range [1].
Wood Thrushes will choose and defend a territory in the winter, much as they do when they are nesting. However, as forests are destroyed in the tropics (including for sun coffee), Wood Thrushes are forced to become nomadic — a case of too many Wood Thrushes and other species, and not enough space. These thrushes must move from place to place, or settle in habitat that is low quality. These birds are less likely to survive the winter than individuals who have territories in a good forest patch [2].
Here in North America, habitat fragmentation is considered another cause of Wood Thrush population declines. As in the tropics, Wood Thrushes can be found in small woodlots or low quality habitat, but their chances of successfully raising a brood are greatly diminished in these situations. In fragmented forests, predators are more common, as are Brown-headed Cowbirds, which lay their eggs in the nests of other birds, often targeting Wood Thrushes. These factors contribute to dramatic rates of nest failure in some locations.
The Wood Thrush and coffee connection is so iconic that this bird has been found on the coffee packages or web sites of Birds and Beans, Coffee for the Birds, Audubon Coffee, and Counter Culture Sanctuary Coffee, to name a few. Wood Thrushes are considered “area sensitive,” needing good, intact forests throughout their annual cycle. High-quality shade coffee plantations represent essential habitat for this species, and your choice of coffee has a direct impact on the survivorship of Wood Thrushes and other birds that rely on tropical forests.
Wood Thrush photo by Eddie Calloway under a Creative Commons License.
[1] Rappole, J. H., G. V. N. Powell, and S. A. Sader. 1994. Remote-sensing assessment of tropical habitat availability for a nearctic migrant: the Wood Thrush. In Miller, R. I. (ed.). 1994. Mapping the diversity of nature. Chapman & Hall, London, England.
[2] Deinlein, M. 1998. A “Sing”-ular Sensation. Wood Thrush: Bird of the Month. Smithsonian Migratory Bird Center.
Revised on January 7, 2022
Thanks for this post! I love the sound of wood thrush's singing. Last summer, I backpacked in Uwharrie Wilderness in N.C., it's a small plot of wilderness attached to a larger national forest, and we heard wood thrush's in the treetops for two days straight. It was penetrating, their sounds bounced off the trees and the forest floor and were an acoustic delight.
Thanks, Darlene. I did around 7 years of Wood Thrush research myself, and they are one of my favorite birds. Hope you find other posts of interest here at C&C as well!
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