Earth & Sky

Our thanks to the following individuals and institutions who assisted in the preparation of this script:

Dr. Craig Rudolph
Research Ecologist
U.S. Forest Service
Southern Research Station
Nagodotches, TX

The following books, articles and web sites were used in preparing this script:

Conner, Richard N., Daniel Saenz, D. Craig Rudolph, William G. Ross, and David L. Kulhavy. “Red-cockaded woodpecker nest-cavity selection: Relationships with cavity age and resin production. The Auk, vol. 115, No. 2, April 1998.

DeWitt, Dan, “Matchmaking for the birds.” St. Petersburg Times, Florida, Oct. 22, 2000, Page 1F.

Burritt, Chris. “Woodpeckers make golf course a love nest.” The Atlanta Constitution, Georgia, June 16, 1999, Page 13A.

U.S. Fish and Wildlife Service ““Wildlife Fact Sheets”“:http://species.fws.gov available in PDF or HTML format; includes fact sheet for red-cockaded woodpecker.

U.S. Fish and Wildlife Service Endangered Species Fact sheet on the woodpecker

Ehrlich, Paul R., David Dobkin, and Darryl Wheye, The Birder’s Handbook: A Field Guide to the Natural History of North American Birds. New York: Simon and Schuster, Inc., 785 pp.

Other useful resources:

McFarlane, Robert W. A Stillness in the Pines: The Ecology of the Red-Cockaded Woodpecker. Norton, 1992.

IN PRESS: Connor, Richard N., D. Craig Rudolph, and Jeffrey R. Walters. The Red-cockaded Woodpecker: Survival in a Fire-Maintained Ecosystem. Austin: University of Texas Press. (to be released in August 2001)

Author’s Notes:

“The endangered red-cockaded woodpecker has adapted fascinating methods of keeping snakes from climbing their nest trees and eating their eggs or nestlings. The woodpecker scales off all of the rough bark on the cavity tree, so the snake can’t hold on to the smooth surface and cannot climb. The woodpecker also pecks holes in the bark of the cavity tree (which is alive) which cause the tree trunk to become covered with sticky sap to deter climbing snakes.”

Red-cockaded woodpeckers typically build their nests 20 to 60 feet up in the trunk of mature longleaf pines (at least 80 to 120 years old and often more than 300 years old) that are infected with red-heart fungus. The fungus softens the tree’s heartwood, making it easier to excavate, although the tree is still alive and the sapwood that surrounds the heartwood is still quite hard for the birds to penetrate. It can take one to three years for excavate a single nest cavity.

How do red-cockaded woodpeckers decide which tree to nest in? Dr. Craig Rudolph, an expert on these endangered birds, examined this question in 1997 and concluded that “sappiness” is a factor. When he compared longleaf pines the woodpeckers had selected as nest sites to other pines in the same forest, he found the birds had selected the trees that leaked the most resin when woundedin other words, the trees that could do a good job of producing a sticky barrier against nest-raiding snakes. If a tree that contains a nest cavity should die, the woodpeckers will abandon the nest site, because dead trees don’t produce the protective sap.

You might expect that the resin deters snakes because they get thoroughly gummed up, but Dr. Rudolph has systematically tested snakes’ ability to climb trees that are protected by resin barriers, and he says that’s not the case. Instead, very small grains of resin get wedged between a snake’s scales. If even a few scales stick together, the snake looses some of its mobility and eventually looses its grip. Dr. Rudolph thinks a snake that falls from a height of 20 feet or more learns to avoid trees with sticky trunks.

Writing in 1939, the naturalist and bird artist John James Audubon said red-cockaded woodpeckers were “abundant.” Why have they been on the endangered species list since 1970? In the last 100 years, much of their longleaf pine habitat has been logged off; the amount of appropriate habitat is estimated to have declined from 92 million acres before European settlement to about 3 million acres today. Once, these birds were found from East Texas and Oklahoma to Florida and north to New Jersey; today the birds are no longer found in Missouri, Maryland or New Jersey. The U.S. population of red-cockaded woodpeckers has gone from an estimated 3 million to only about 12,500 birds.

Even in areas where pines have been replanted, the birds still have trouble making a home, since young trees just aren’t big enough around to have room for a nest cavity, and red-heart fungus generally doesn’t strike trees till they are big and mature. Also, young forests often have a thick understory of shrubs, and the vegetation that grows close to nesting trees can give snakes another avenue up into the nest hole. (In the past, natural fires kept the understory of mature pine forests clear of vegetation.)

Scientists are giving the birds a helping hand by constructing nest boxes that can be set into the trunks of smaller trees. But even some birds move right in, it can take weeks of well-drilling before enough sap oozes out to make an effective snake barrier.

One fascination aspect of red-cockaded woodpeckers is that these birds nest in family groups, and often, the pair of parent birds will have “helpers at the nest”, offspring from a previous nesting that help them raise another clutch.

Not only do red-cockaded woodpeckers need appropriate trees for nest sites, but each bird in the group needs its own tree cavity as a night-time “roosting site.” That makes the lack of appropriate trees even more of a problem.