23 May
2020

Posted in: frog, RINHS, Uncategorized
By Hugh    No Comments

An Army of Frogs, a Knot of Toads: Spring means a big night for amphibians

Wood frog photo by Lou Perrotti.

You can hear them on a mild spring night: what sounds like a flock of ducks, quack-quacking from a nearby freshwater pool. But these are no ducks; instead, they are Wood Frogs, calling out to invite females to have a mating swim in the pool. Wood Frogs are typically the first inhabitant of the pools heard in the springtime, even before the more popular Spring Peeper toad. It means that life is beginning again, and frogs, toads, and other creatures are celebrating it by perpetuating the species. “With the right amount of rain, the spotted salamanders also make their nuptial marches to the vernal pool,” said Lou Perrotti, Director of Conservation Programs for Roger Williams Park Zoo.

The Big Night

As temperatures warm and April showers begin, Perrotti says there is a good chance of seeing what is known as a “big night”. “It’s a huge migration, typically happening with the right balance of temperatures and rainfall. In May, you can have these massive migrations to the vernal pools.” Vernal pools are temporary pools of water that form from snow melt or small springs that do not harbor fish, which would eat the eggs.

The males arrive first. “That’s where the call comes in.” Once that call comes out, it triggers the female to come to the pools as well. Frogs and salamanders typically return to their original grounds year after year.

The form of reproduction is called amplexus, where the male grabs onto the shoulders of the female and hangs onto her. He fertilizes the eggs that she lays. (Fun fact: frogs lay their eggs in clusters, while toads arrange theirs in strings.) The hundreds of eggs will hatch within a week, and the tadpoles are on their own. By the time they hatch, the parents have returned to their homes in the woods. “They’re outta there,” Perrotti says.

Although the idea seems simple enough, trouble for the prospective parents begins even before the pairs meet. The main issue: auto traffic. “Sometimes people put up signs, and even close roads on a big night. Information about the location of hotspots is limited. My god, the carnage we see. It’s hard. The more roads we build that crisscross the habitat, the more the increase in mortality.”

Spadefoot toad photo by Lou Perrotti.

On a more positive note, Perrotti has had some good news for one species. Spadefoot toads, which get their name from spade-like growths on their hind legs used for digging, are state endangered. With only two known populations in the state, Perrotti was surprised to see an explosive new population in a national wildlife refuge. He and a team rescued nearly 800 tadpoles (“The spot was going to dry out”, meaning the young would have died otherwise). Perrotti raised them at his house until they were large enough for release. Some toads were later returned to the refuge, while others were placed in a newer location. As of this moment, Perrotti reports that he is raising roughly 50 in his own home as a hedge that the mature frogs will do better when released this year. “I wanted to make sure I paid every attention to detail,” he explained.

Frogwatch

Lou Perrotti’s love for amphibians extends to his enthusiasm for making converts. One of his best tools is the Zoo’s Frogwatch Program, which enables kids, families, and enthusiasts of all ages to collect real scientific data concerning the whereabouts of the frogs and toads around the state. He brought the idea to the Zoo in 2008, and quickly became an important figure in its survival. After his first year running the program and training some 200 participants, he successfully piloted the program to the American Zoo Association (AZA) when the original federal funding was cut. “Now it’s AZA’s flagship program.”

“It’s a great way to have people bring data for science. The training is straightforward enough to be absorbed by a non-scientist, but the data is still vital.

Common toad photo by Lou Perrotti.

“Through the training, people have a chance to learn about a group of creatures they may not have known much about before. They learn about their importance to the ecosystem. It fires people up to be able to say, ‘we went out there and saw a salamander, heard an owl, and obtained information that can be put into a database that can be used in the future for the conservation of the species’”. Over a decade later, Perrotti says they still train hundreds each February and March.

“We’re inspiring that next generation to give a care about frogs and salamanders, and things that are non-charismatic species. These moments in these programs are what will inspire young people to be our next conservation leaders. That’s why I do this.”

Learn more about Rhode Island frogs and toads, as well as hear their calls, at Frogwatch RI’s website: https://www.aza.org/frogwatch-usa-rhode-island .