Can a little frog tell you how good your water is?

Wood Frog Calling Photo by: Scott Gillingwater

Wood Frog Calling
Photo by: Scott Gillingwater

Thank you to Larry Noonan and his volunteers for doing such an amazing job collecting frog call data in Altona Forest, Pickering Ontario! This site is special as it contains both natural and manmade wetlands, giving frog researchers a unique insight into frog habitat preferences and sensitivities. Monitoring frog populations is a great way to determine your wetland’s health and the variation of different species present.

But can a little frog tell you how good your wetland is?

It’s all in the skin. Frogs breathe and drink through their highly porous skin. This skin makes them very well adapted to live in a wetland, but it also means that frogs are very sensitive to pollution. They can easily absorb harmful substances such as herbicides and pesticides. By keeping track of frog populations in your area you can gain insight into to health of your water supply.

The likelihood of a frog egg becoming an adult frog is approximately 1/1000, depending on the frog species and environment. Frogs lay anywhere from 100 to 10,000+ eggs, and it’s because of this high number that they can survive the pressures of predators and environmental changes. Frogs reproduction has evolved to cope with natural changes to their environment, such as droughts or floods, by laying so many eggs each year.

One way frogs cope in competitive environments is to breed at different times of the year. This means different species will be emerging from the water as adults while others are just hatching from their eggs. This is why we hear different species of frogs calling at different times during the year.

Larry Noonan and his team used a Song Meter to monitor Altona Forest’s frog population. A Song Meter is a sound recorder that is programed to record noise at a specific time during the day, throughout the year. See below to check out their findings.

Recordings started on Friday March 21 and ended on Tuesday July 1. Recordings were made for 30 seconds every half hour 24 hours a day.

  1. Woodfrogs were first recorded on April 9 at 8:00 pm with the last recorded on May 11 at 9:00 am.

  2. American toads were first recorded on May 4 at 9:30 pm and last recorded on May 29 at 9:30 pm

  3. Gray treefrogs started calling on May 26 at 6:30 pm and continued through June 28 at 7:30 pm.

  4. Green frogs were first heard on May 11 at 9:00 pm and continued calling until 6:30 am on the last day of recording on July 1.

  5. Leopard frogs were not heard this year but were seen on a couple occasions.





The best ways to help frog populations in your area is by protecting and restoring important wetland areas that are already establish breeding sites. Littler clean ups, inspiring appreciation of nature through education, and having a community voice that stands up for policies and laws that protect wetlands are great ways to ensure stable and abundant frog populations for future generations. You can also become a frog researcher by participating in FrogWatch Ontario. A province wide programme that tracks frog population through individuals like you!