Birds and Battalions

Editor's note: The following feature was provided to The Birding Wire by Craig Springer and Lesli Gray, external affairs for the Southwest District of the U.S. Fish and Wildlife Service. -JRA

http://www.theoutdoorwire.com/image_archive/2253793.jpg> Managing for healthy native bird habitat on Fort Hood is an essential task for a terrain that regularly accommodates a high volume of military exercises. Gil Eckrich

War transformed the nature of farmlands of central Texas. What had been a checker-spotted landscape interspersed with mosaics of oak-juniper woodlands turned into a busy Camp Hood during World War II. The Soldiers from central Texas would end up in Europe to help bring the war against Germany to a close. The temporary military camp later became the permanent Fort Hood, the largest U.S. Army facility in the nation encompassing over 218,000 acres and supporting more than 371,000 people including some 50,000 well-trained Soldiers.

Today, the sounds of live weapons fire from helicopters, the roar of mechanized combat vehicles, the clomp of metal-tracked tanks rumbling like massive bulldozers with cannons cruising over the terrain are all common sights and sounds at Fort Hood.

And as of late, so are two songbirds: the golden-cheeked warbler and the black-capped vireo. In seemingly incongruent fashion, the wispy songs of these two federally endangered birds embalm the springtime air of Fort Hood.

http://www.theoutdoorwire.com/image_archive/2253795.jpg> The showy golden-cheeked warbler has been considered endangered since 1990. Scientific research and conservation work on Ft. Hood has improved its lot. USFWS

The golden-cheeked warbler wears a splash of yellow on its head like the panache of an officer of old. It draws attention to itself. It's a shard of sunshine glommed to the bird's head. As showy as it is, the golden-cheeked warbler has other notoriety. It's been listed as endangered since 1990. The bird is a true native Texan, with its breeding range entirely within the Lone Star State, including Fort Hood. Habitat loss through conversion of natural areas to parking lots and housing subdivisions, urbanization in general, caused the bird's numbers to decline. Having a fair amount of habitat on a military installation has been a benison for the bird.

When the warblers return from their wintertime haunts in Mexico and Central America, nesting habitat at Fort Hood welcomes them home. The number of birds on the fort are on the rise, and it's not been by accident.

The warbler was discovered on Fort Hood lands in the 1950s and biologists seeing the conservation need, recommended to the fort's commanding general in 1970 that blocks of land be set aside for the bird. The Army abided.

In the 1980s, another bird species came into view. Surveys by scientists revealed that the black-capped vireo was declining in the northern part of its summertime breeding range, which included Fort Hood.

http://www.theoutdoorwire.com/image_archive/2253799.jpg> Goggle-eyed, the black-capped vireo builds distinctive cup nests in small stands of trees characteristic of central Texas – and Fort Hood. Conservation work and scientific research has put its population numbers on an upward trend all the while military readiness goes undiminished. Gil Eckrich

Though not as showy as the warbler, the vireo suffers for many of the same reasons. But add nest parasitism into the mix as well; brown-headed cowbirds which make no natural effort to build a nest and raise their own offspring let other bird species do it for them, including the vireo. And that has aggravated the matter for the vireo. The black-capped vireo is adorned with its namesake black "cap" and what looks like white spectacles bridging its face. They sing an emphatic song perched in shrubby oak mottes where they build intricate hanging cup nests fastened with spider silk. They eat bugs and spiders gleaned from leaves and tree branches sometimes deftly hovering while doing so.

The vireo was listed as endangered in 1987. Two years later, surveys of the bird revealed 143 males living on Fort Hood. Their number grew and in the 1990s the population on Fort Hood was too large to accurately assess. A new method of measuring bird numbers came into use about 2005; it revealed an upward trend with an estimated 7,500 male black-capped vireos living on Fort Hood by 2014. The U.S. Fish and Wildlife Service (Service), recognizing these accomplishments, greatly appreciated the unexpected conservation partnership with Fort Hood.

The golden-cheeked warbler has seen similar rises as well. Just this past year, biologists predicted there were 7,382 male warblers on the fort. Indeed, Fort Hood is home to the largest known population of these warblers and vireos. This is particularly noteworthy considering that most of the vireo's summer range and all of the warbler's summer range exists in Texas, where 97 percent of land ownership is in private hands.

Fort Hood has been a willing and eager partner in conservation of these rare birds for almost a quarter century. "Our goal has always been to make the endangered species at Fort Hood invisible to the Soldier training on the installation. Now, with the help of the Service, the next version of the training maps does exactly that," said Tim Buchanan, Fort Hood's Chief of Natural and Cultural Resources.

http://www.theoutdoorwire.com/image_archive/2253797.jpg> Soldiers train near a trap on Ft. Hood that is used to reduce nest parasitism on warblers and vireos by brown-headed cowbirds. Gil Eckrich

The fort additionally opened itself to scientists from academia and government agencies to conduct research. Thanks to Fort Hood's cooperative approach, the science available to advance conservation efforts for the warbler and vireo, as well as many other species found at Fort Hood, has flourished. For instance the use of miniature video cameras to monitor vireo nests revealed that Texas rat snakes are significant predators of vireos on the nest—something previously unknown to science. Research on the birds benefits the Army too; they've learned that the natural habitats used by these species are necessary to sustain lands used for training Soldiers. Tanks and artillery fire are hard on the land. Managing for healthy native habitat on the fort is an essential task for terrain that regularly accommodates a high volume of military exercises.

"The Service greatly values our partnership with Fort Hood. They have gone above and beyond to work with us and to address the conservation needs of the golden-cheeked warbler and black-capped vireo," said Omar Bocanegra, Service biologist. "Thanks to the cooperative relationship between the Service and Fort Hood, we have greatly enhanced the information on both species. They've clearly demonstrated that it is possible to successfully manage endangered species and military preparedness."

Army staff has taken ownership in managing the fort not only for national defense but for wildlife and natural resources as well. As a result of more than two decades of research and conservation work at Fort Hood on the vireo and warbler, the base operates without most of the training restrictions that had previously been in place. Fort Hood's efforts have helped the Service meet—and by some measures, exceed—its population recovery goals for both bird species. Most importantly, Fort Hood has demonstrated that natural resources entrusted to the Department of Defense's care are not only sustained, but can be improved, all while ensuring that military training and testing are uncompromised. Fort Hood serves as a model for other military installations across the country, clearly demonstrating that national defense and conservation are not mutually exclusive.