Toad Trackers

Houston Zoo's Toad Trackers

Students that are part of the Houston Zoo's Toad Tracker program measure a coastal plains toad. (Photo courtesy of the Houston Zoo.)

As we’ve mentioned in this blog before, the Panama Amphibian Rescue and Conservation Project partners are not just trying to save species of frogs in Panama, but also in their own backyards. Here is an account of one local project that partner the Houston Zoo has taken on.

In the spring of 2010, the Houston Zoo piloted a new conservation education program called Toad Trackers. In the first year of this one-of-a-kind, interactive program, the Houston Zoo ‘tracked’ 39 coastal plains toads (Bufo nebulifer) and ‘discovered’ 88 new amphibian enthusiasts.

Led by the Zoo’s Conservation Programs Manager Rachel Rommel and assisted by the Zoo’s Education Department, Toad Trackers expands on the idea of “citizen science,” such as Frog Watch USA and the North American Amphibian Monitoring Program, introducing students to field research methods and tools used by conservation biologists and wildlife professionals, such as Kestrel meters, calipers, GPS units, microchips and scales to track, monitor and assess the health of toad populations.  Toad Trackers was made possible by a grant from the Texas Parks and Wildlife Department’s Community Outdoor Outreach Program.

On select nights (warm and wet) on Zoo grounds, the supervised students conduct a ‘toad round-up,’ collecting every toad that can be found for processing and data collection.

The coastal plains toad has adapted quite well to living amongst humans and has survived despite a shrinking and fragmented habitat.  The large population of this particular toad and its ability to thrive in urban areas makes it a perfect candidate to study, both from a convenience and an environmental impact perspective.

When the toad round-up begins on sticky Houston summer nights, the kids weigh, measure, determine gender, note any mutations of each toad and record its GPS coordinates.

One of the Zoo’s conservation biologists, oftentimes Paul Crump, the Houston Zoo’s Amphibian Conservation Programs Manager, then inserts a pit tag into each toad (like the microchips in your cat or dog) and the students then release the toad where it was initially captured.

Subsequent toad round ups during the same or following year will provide valuable information (through the ability to individually recognize toads) on growth rates, reproductive events, and movement patterns.

In addition to encouraging a new generation of wildlife biologists, Toad Trackers also provides a forum in which students can learn about amphibian ecology, global amphibian extinctions and why monitoring local amphibian populations is important to detecting declines in our own region.

Houston Zoo's Toad Tracker program

A student involved in the Toad Tracker program holds one of the toads she caught. (Photo courtesy of the Houston Zoo)

Additionally, the data collected through Toad Trackers will be used to publish a peer-reviewed paper on native toad populations based on the world of citizen scientists.

In 2010, the Toad Trackers program was incorporated into the Houston Zoo’s home schooling program; Camp Zoofari, the Zoo’s summer day camp program; Zoo Crew, the Zoo’s teen volunteer program; and with one community outreach group, the Hispanic Women’s Network of Texas.

In 2010, Toad Trackers captured a total of 39 Bufo nebulifer. Of those, 77 percent were female, 21 percent were male.  The gender of two percent of the toads could not be determined due to life stage.

The average SUL was 69.22 mm for female toads and 60.1 mm for male toads, well within normal range for the species.  The average weight was 38 grams for females and 27.44 grams for males. Our citizen scientists also detected Rio Grande chirping frogs and green tree frogs on Zoo grounds on most field evenings.

Students reported one recapture of a female toad.  Named “Emily,” the toad traveled .02 miles from her last location, had grown 1.7 mm and increased her weight by 2 grams.

All but one animal (too small) was AVID microchipped.  The proportion of animals marked in the first sampling in 2010 that are recaptured in the second sampling this year can be used to calculate an estimate of the overall population size of the toads on Zoo grounds.

The students made some interesting observations in 2010.  One female Bufo nebulifer was found approximately 24 inches off the ground sitting inside a tropical plant by the Zoo’s reptile house. Neill and Grubb (1971) found Coastal Plain toads from 2 to 5 meters above the ground in oak trees; they can be considered arboreal in that individual toads will find tree holes and may use them repeatedly for periods of weeks.

On numerous occasions, students observed female Bufo nebulifer vibrating and chirping upon capture.  With this particular species, females are not generally known to display release calls as this is considered a male behavior.

Brian Hill, Houston Zoo