Spring Frog Surveys are Starting!

To some people the sight of the first robin of the year signals the beginning of spring. For others such as myself, the true harbingers of spring are our frogs. When these cold-blooded creatures emerge from hibernation and begin singing, spring has arrived and so spring frog surveys are starting.

Wood frog sitting on a leaf.
Photo Credit: J. Boxall (2009). Wood frog sitting on a leaf.

Timing Windows

Ontario is home to twelve species of frogs and toads. What is a surprise to many, is that half of these species spend most of their lives on land and only return to the water to mate. In central Ontario the first warm, rainy nights of late March to mid-April signals the start of frog mating season. Wood frogs, Western chorus frogs, and Spring peepers are the first frog species to appear, and in some cases before their breeding ponds are fully thawed! Within days these ponds can echo with the chorus of male frogs as they call in earnest for a mate. As quickly as they appear, species like the Wood frog finish their breeding cycle and return to the forest where they will remain until the following spring.

Spring is an exciting time of year for NEA biologists as it signals the start of the field season and frog surveys are one of our spring priorities . Biologists watch the weather forecasts closely to predict when these vocal breeders will first appear. The scheduling of night-time site visits is restricted to a small window of opportunity dependent on the weather and the species mating habits. Surveys for the later emerging frog species such as Grey tree frogs, Green frogs and Bullfrogs take place through May and June.

Acoustic Frog Surveys

NEA biologists can also use the Song Meter SM4 acoustic recorder in order to assist with frog inventories. This sophisticated piece of recording equipment allows us to record frog calls without having to be on site overnight. This saves time and money. Back at the office, sophisticated software can filter the recordings quickly and cluster frog calls for quick identification.

Citizen Science and You

An excellent resource for more information on Ontario’s reptiles and amphibians is the Ontario Nature Reptile and Amphibian Atlas (ORAA). This ambitious project collects sighting records of all of the Provinces’ Herptile (collective name for reptiles and amphibians) species.

Ontario Nature Reptile and Amphibian Atlas map of American bullfrog occurrences.

Citizen-science based, members of the public are encouraged to submit their herptile sightings. Records are vetted by trained professionals before being entered in the data base. Ontario Nature has developed a robust and free mobile application that serves as a field guide to Ontario’s ‘herps’ in addition to facilitating sighting submissions. This application also includes audio recordings of all the frog calls.

For more information regarding frog surveys or other wildlife inventories, please contact one of our wildlife biologists.