A reintroduction program for the Texas horned lizard in Parker County was described at the January 2013 meeting of Cross Timbers Native Plants.
Diane Barber, curator of ectotherms at the Ft Worth Zoo, described the program, assisted by Eileen Porter. The Ft Worth Zoo has had a breeding program for the Texas horned lizard since 2005 and is conducting the reintroduction program. Eileen and her husband Richard are the owners of one of the properties where the reintroductions are taking place, and are also members of Cross Timbers Native Plants.
Horned lizard declines across north central Texas have been attributed to habitat alteration, invasive red fire ants, urban development, pesticide usage, and other factors that merit study. Although many of these ecological pressures still exist, there are native habitats that have been restored and are managed in an environmentally responsible manner, which are potentially capable of supporting reintroduced horned lizards.
The Texas horned lizard, Phyrnosoma cornutum, is protected as a threatened species in the state of Texas and is listed as the official state reptile. Perhaps more than any other native animal, the ‘Horny Toad’ is identified with and beloved by Texans. The species is held in high esteem and garners vast support for its conservation and reintroduction into areas where it once lived.
In the fall of 2010, representatives from the Fort Worth Zoo, Texas Parks and Wildlife Department, Texas Christian University and the Horned Lizard Conservation Society met to take action. The plan was to start the first-ever reintroduction program for Texas horned lizards.
Previously other conservationists had tried to relocate wild horned lizards, but their strong native instincts sent the lizards constantly roaming and trying to make their way home. Since relocation was not successful, they decided to see what would happen if they reintroduced horned lizards from a captive breeding program.
The reintroduction effort began in the summer of 2011 and continues today. Some of the research issues include identifiication of the appropriate age class for reintroduction, measurement of juvenile vs. adult dispersal and survival, survival of wild-caught vs. captive-bred individuals, effectiveness of different release techniques, habitat usage and predator avoidance.
Two sites were chosen for the reintroductions, based on historical presence of horned lizards, nature of the habitat and especially the presence of harvestor ant mounds. Harvestor ants are the only food which the horned lizards eat. Horned toad habitat is the same habitat as quail habitat.
The horned toads are initially kept in pens over harvestor ant mounds at the relocation site to help them adjust to their new home. After ten days they are released from the pens and are tracked with radio transmitters glued on their backs.
A total of 13 lizards have been released on the Porter property. Currently the zoo is tracking three, all of which are hibernating underground for the winter. Others released on the property are either known dead or have been lost. One transmitter was found in the belly of a copperhead.