Conserving the Wood ThrushProject Summary
Learn about the life history, distribution, ecology and conservation of the Wood Thrush, a songbird in steep decline. Using written materials and sources listed below, write a report on the threats it faces and what is needed to help it survive. For those who live in areas where the Wood Thrush is not native, select another declining songbird and follow the same suggestions.
The Wood Thrush (Catharus mustelinus) is one of the most melodious songbirds in the world. Its beautiful, fluted song echoes through eastern North America's woodlands. In the words of Arthur Cleveland Bent, author of a series of authoritative life history studies of American birds: "The nature lover who has missed hearing the musical bell-like notes of the wood thrush, in the quiet woods of early morning or in the twilight, has missed a rare treat. The woods seem to have been transformed into a cathedral where peace and serenity abide. One's spirit seems truly to have been lifted by this experience."
The Wood Thrush is also useful to forest ecosystems, consuming vast amounts of insects. Unfortunately, its populations have declined in recent years from 40 to 80 percent, depending on the area. Major causes include the destruction of both its nesting and wintering forests, combined with parasitism on its nests by the Brown-headed Cowbird, a bird that lays its eggs in the nests of other birds. These eggs tend to be larger than the eggs laid by the Wood Thrush, and the aggressive chicks crowd out the thrush chicks. Wood Thrushes are closely related to the familiar American Robin, a common denizen of suburban yards and forests. Unlike the Robin, however, the Wood Thrush is not common in suburbs and backyards. Although the species was occasionally seen near homes and villages in the first half of the 20th century, today it breeds only in undisturbed forest tracts. Its forest habitats have become fragmented into smaller and smaller blocks, causing the species to disappear from many areas.
Wood Thrushes migrate to Mexico and Central America each winter. They seek out old-growth rainforests from southern Mexico through Panama. Within the past 40 years, their forests have been logged and often converted into grazing land or agricultural fields. Researchers tracking these birds to their wintering grounds have discovered that they stay in the same area, even though it has been destroyed, and usually die within a short period from starvation or predation. The decline in this species' population was discovered through Breeding Bird Surveys conducted annually by the US Department of Interior. The Wood Thrush is close to endangered status, and conservation is critical to prevent its decline to extinction.
Other North American songbirds that migrate to tropical areas have declined as well. These birds, known as neotropical migrants, include tanagers, orioles, warblers, thrushes and vireos. These colorful birds brighten our forests and orchards, consume harmful insects and play important ecological roles. Almost all are in decline, some far more precipitously than others.
o Find out about the Wood Thrush, using the text in this book (see index), sources listed below and those available in your library and through computer on-line searches.
o Write a report answering as many of these questions as possible:
- What does the Wood Thrush look like?
- How large is it?
- Are males and females different in size or appearance?
- What is its diet?
- What type of woods does it prefer (for example, dry, old-growth forest or
cool, damp forest near streams)?
- Does it build its nest on the ground, in bushes, or on tree branches?
- How large a territory does it establish?
- When does it sing? Describe its song (see reference on obtaining
- How long does it live?
- What are its breeding and wintering ranges?
- How did early naturalists, such as John James Audubon, describe Wood
Thrushes in the 19th century? (See Audubon and Coues book below.)
- How serious is the threat from Brown-headed Cowbirds who lay their eggs in
Wood Thrush nests? (This was noted even in the 1930s by Bent (1964), and
later by other authors such as Rappole et al. (1989), and Terborgh
- How can people contribute to protecting both the breeding and wintering
habitat of the Wood Thrush?
o Field study: If you live east of the Mississippi River in the range of this species, visit an area where Wood Thrushes live. First, listen to the recording of their songs (see below). Often they are more easily heard than seen. Do not approach a nest or disturb birds by playing recordings of their songs. Photograph the woodland setting where you hear the Wood Thrushes and try to observe them quietly from a distance. Describe what wildflowers, trees and other birds you see. If you live outside their range, see films listed below and listen to recordings or select another species of thrush or songbird found in your area that is in decline as a result of habitat loss, especially forests. Consult your local Audubon Society, the US Fish and Wildlife Service, your state's Natural Heritage Program or the bird count programs listed below.
o Conservation project: Find out if there is a woodland near your home where Wood Thrushes breed. The local National Audubon Society or birding organization can provide this information. If so, is it protected from logging? Can your class or school help in protecting a woodland where they breed?
o Participate in a survey of native birds through programs sponsored by local Audubon or birding organizations. The American Birding Association publishes an annual guide, "Volunteer Opportunities for Birders," which lists day-long programs and more extensive studies. Available for $2 from Volunteer Directory, ABA Sales, P.O. Box 6599, Colorado Springs, CO 80934; 800-634-7736. For further ideas, see Nickens reference below.
o Why are some species rare and others common? Compare the Wood Thrush with the American Robin by answering the following questions: Does the Robin migrate? If so, where does it migrate? Are there dangers in its wintering ground, such as deforestation? Where does the Robin nest? Is there more habitat for American Robins or for Wood Thrushes? Explain why. Are there threats to the American Robin?
Books and Publications
Adams, George. 1994. Birdscaping Your Garden. A Practical Guide to Backyard
Birds and the Plants that Attract Them. Rodale Press, Emmaus, PA. (On page
87, the Wood Thrush is profiled, providing information about migration,
breeding range, nesting, feeding, garden bushes and fruiting plants
that it will eat, as well as the woodland habitat it prefers.)
Audubon, Maria R. and Elliott Coues. 1986. Audubon and His Journals. Vols. I
and II. Dover Publications, New York. (First published in 1897, Audubon's
journals were collected by Maria Audubon with notes by the distinguished
naturalist Elliott Coues. Wood Thrushes are mentioned many times.)
Bent, Arthur C. Life Histories of North American Thrushes, Kinglets, and Their
Allies. First published in 1949 and reprinted by Dover Publications, New York, 1964, pages 101-122.
Bull, John and John Farrand, Jr. 1977. The Audubon Society Field Guide to
North American Birds. Eastern Region. Alfred A. Knopf, New York. (A photo
Cherry, Lynne. 1997. Flute's Journey. The Life of a Wood Thrush. A Gulliver
Green Book. Harcourt Brace and Company, San Diego, CA; New York.
DeGraaf, Richard M. and John H. Rappole. 1995. Neotropical Migratory
Birds. Natural History, Distribution, and Population Changes. Comstock
Press, Cornell University, Ithaca, NY. (This book has range maps of all
North American breeding birds that migrate to Latin America and several
pages of discussion of each species.)
Farrand, John Jr. (ed.). 1983. The Audubon Society Master Guide to
Birding. (Has color photo of adult at nest with chicks and a color painting
of the juvenile.)
Forbush, Edward Howe and John Bichard May. 1959. A Natural History of
a Bird of Eastern and Central North America. Bramhall House, New York,
Geffen, Alice M. 1978. A Birdwatcher's Guide to the Eastern United States.
Barron's, Woodbury, NY. (This and the Pettingill book below list major
parks, refuges and public lands by state; under each is a list of birds
to be seen.)
Hagan, John M. III and David W. Johnston (eds.). 1992. Ecology and
Conservation of Neotropical Migrant Landbirds. Smithsonian Institution
Press, Washington, DC. (This book is not indexed. It is a collection of
papers from a 1989 symposium, containing much information on the problems of
songbirds, including the Wood Thrush, especially an article on destruction
of its habitat in Veracruz, Mexico, on pages 337-344.)
Harrison, Colin. 1978. A Field Guide to the Nests, Eggs and Nestlings of
North American Birds. The Stephen Greene Press, Brattleboro, VT; Lexington,
MA. (This book describes the nest and nestlings and gives the nesting dates;
a color photo shows the egg.)
Keast, Allen and Eugene S. Morton (eds.). 1980. Migrant Birds in the
Neotropics: Ecology, Behavior, Distribution and Conservation. Smithsonian
Institution Press, Washington, DC. (Papers submitted at a symposium.
Many discuss the threats that migrant songbirds, including Wood Thrushes,
face on their wintering range. The introduction gives an overview of the
Kricher, John C. 1988. A Field Guide to the Ecology of Eastern Forests.
North America. The Peterson Field Guide Series. Houghton Mifflin Co.,
Boston, MA. (This book contains information on hundreds of species of plants
and animals, many of which are illustrated with color photos.)
National Audubon Society Nature Guides. North American's Eastern Forests
and Wetlands. Alfred A. Knopf, New York.
Nickens, Eddie. 1997. Beyond the Life List. Wildlife Conservation magazine, July/August. (Wildlife Conservation Society, Bronx Zoo, Bronx, NY 10460.)
(This article describes the work of volunteers who participate in surveys,
banding, birdfeeder studies and other projects relating to North American
songbirds; it provides addresses and phone numbers of various
Peterson, Roger Tory. A Field Guide to the Birds. A Complete Guide to All
the Birds of Eastern and Central North America. Houghton Mifflin Co.,
Boston, MA. (This classic guide has excellent illustrations, breeding range
map and descriptions.)
Pettingill, Olin Sewall, Jr. 1977. A Guide to Bird Finding East of the
Mississippi. Oxford University Press, New York. (Although many of the areas
described in this indexed book have changed since it was first written,
many are protected sanctuaries, parks and reserves.)
Rappole, John H., Eugene S. Morton, Thomas E. Lovejoy III and James L. Ruos.
1983. Nearctic Avian Migrants in the Neotropics. US Fish and Wildlife
Service and World Wildlife Fund, Washington, DC. (This publication is not
indexed, but is a well-organized report on North American songbirds, their
ecology and threats. Range maps show breeding range as well as wintering
range of all migratory species.)
Sibley, David A. 2000. The Sibley Guide to Birds. Alfred A. Knopf, New York.
(Considered one of most inclusive guides because it includes information on
subspecies, varieties and other aspects not covered in most guides.)
Stokes, Donald and Lillian. 1996. Stokes Field Guide to Birds. Eastern Region.
Little, Brown & Co., Boston, MA. (Color photos.)
Terborgh, John. 1989. Where Have All The Birds Gone? Princeton University
Press, Princeton, NJ. (Many mentions in the text, see index; this is a
landmark book on the decline in North American songbirds, exploring their
problems on both the breeding and wintering grounds)
Yoon, C.K. 1994. More Than Decoration, Songbirds Are Essential to Forests'
Health. The New York Times, Nov. 8.
Organizations and Governments
National Audubon Society, 700 Broadway, New York, NY 10003. (212-979-3000);
or local chapters.
Conservation International, 1015 18th St., NW, Suite 1000, Washington,
Cornell Laboratory of Ornithology (Breeding Bird Censuses), 159 Sapsucker
Woods Rd., Ithaca, NY 14850-1999 (607-254-2473).
Institute for Bird Populations, P.O. Box 1346, Point Reyes Station, CA 94956;
The Nature Conservancy, 1815 North Lynn St., Arlington, VA 22209 (and field
offices throughout the country).
Natural Heritage Programs in every state in Department of Wildlife or Fish and
US Fish and Wildlife Service, 4401 N. Fairfax Dr., Arlington, VA 22203.
Breeding Bird Survey, Biological Resources Division, US Geological Survey,
Patuxent Wildlife Research Center, 12100 Beech Forest Rd., Laurel, MD
Fish and Wildlife Reference Service, 5430 Grosvenor Lane, Suite 110, Bethesda,
MD 20814 (800-582-3421).
The Peterson Field Guide Series. A Field Guide to Bird Songs of Eastern and Central North America, recorded by the Cornell Laboratory of Ornithology. 2nd edition. Houghton Mifflin Co., Boston, MA. 1983. Two tape cassettes. (Wood Thrush on Side 3, Band 4). Other recordings, such as the Stokes audio guides, are also available.
"On a Wing and a Song." This Canadian Broadcasting Company film gives an
overview of the songbird decline in Eastern North America, illustrating the
vast areas of boreal forest where many of these birds nest in Canada, which
has been logged. It addresses the loss of habitat in their tropical
wintering grounds; the millions killed by colliding with skyscrapers and
antennas during migration; and the parasitism by cowbirds.
"On a Wing and a Prayer." A similar title to the above film, this film focuses
on an Illinois woodland and the decline in songbirds, primarily Wood
Thrushes. The parasitism by cowbirds is dramatically shown: Wood Thrush
chicks starve to death next to huge, fat cowbird chicks. This film also has
a teacher's guide.
(See Video section for more detail and distributor list.)