At toads' last stand, reserves hop to it

BASTROP STATE PARK — One voice begins, high and shrill. After 14 seconds, as the first fades, another voice joins in, then another and another. Eventually, a chorus of more than 100 lovelorn voices has formed.

Up until the 1980s, this was not an uncommon occurrence in Bastrop County. It's a sound heard only in Texas — the mating trill of the endangered Houston toad.

(Photo: Bret Gerbe for the Austin American-Statesman) The endangered Houston toad can grow up to 3.5 inches long.

Fewer than 300 adult Houston toads remain, researchers say. Rapid urban development has eliminated most of their habitat, and Bastrop State Park has become their final stronghold.

To combat the losses, 140 Houston toads were released into the park shortly after in September. Researchers released an additional 220 toads in Austin County. Scientists and park officials hope the toads will survive to breed and restore some of the lost population.

"At this point, it's triage," said Michael Forstner, a biologist at Texas State University-San Marcos. "The population is still declining."

The toads were released at the same shallow pond where researchers collected them as eggs seven months ago. Texas State researchers took the eggs to the Houston Zoo, where they hatched and reached maturity.

The toads grow up to 3.5 inches long and vary in color from light brown to gray or purplish gray, sometimes with green patches. Their pale undersides often have small, dark spots. Males have a dark throat, which appears bluish when distended.

After breeding, female toads lay strings of up to 6,000 eggs that hatch into tadpoles before they metamorphose into toadlets. The first two months are the most dangerous in a toad's life. Young toads are food for insects, fish, snakes, birds and raccoons. The toads need standing water to breed, making them vulnerable to drought. In the wild, each egg has less than a 1 percent chance of surviving.

Named after the city where they were first discovered, Houston toads have lived in the forest and woodlands of eastern Texas for more than a million years but have largely disappeared amid rapid development, Forstner said. The toads were found in fewer and fewer counties, until the only Houston toads left in Houston were at the zoo.

Houston toads will remain on state and federal endangered species lists until they have three self-sustaining populations that can interact with one another.

Houston is too developed for the toads to have a good chance of survival there, Forstner said. And Bastrop State Park is home to just one population, so scientists are encouraging area landowners to be toad-friendly.

In 2007, the Texas Parks and Wildlife Department approved $167,488 for a Landowner Incentive Program grant that provides money for landowners to improve Houston toad habitat on their properties. The state contributed $72,088; the remainder of the money came from private donations, the Environmental Defense Fund and the Houston Zoo.

Bob Long's family, which owns the Round Bottom Ranch in Bastrop County, was awarded money through the program in compensation for restricting where their cattle roam during the toad's breeding season, from January to June.

"I'm not overly concerned about the toads, but I'm doing my part as a conservationist," Long said.