The below is an edit of an original article by Cataraqui Regional Conservation Area.
Not that long ago, leopard frogs were the most abundant and widespread frog species in North America. It was hard to visit a marsh, stream or pond without coming across a number of these interesting looking spotted frogs. Since the 1970s, however, massive declines in Canada and the United States have significantly reduced their numbers. The declines are attributed to a combination of ecological factors, such as pollution, deforestation, habitat loss, lawns and mowing and pesticide use.
They are more susceptible to changing environmental factors than most species because of their highly permeable skin that absorbs any toxins in their surroundings. Because these frogs are extremely sensitive to chemical pollutants, they are often used as an ecological indicator species. This means that biologists studying particular areas are able to judge changes in pollution, disease, habitat, etc. by studying the frog population in the area.
Northern leopard frogs are named for the array of dark spots that adorn their backs and legs. They are green in color with a white underside and light-colored ridges on either side of their backs. Their range is most of northern North America, except for the Pacific Coast. They generally live near ponds and marshes, but will often spend time in well-covered grasslands as well, earning them their other common name, the meadow frog. In winter months, they avoid freezing by hibernating underwater in water bodies that are deep enough to prevent freezing solid.
Northern leopard frogs will eat just about anything they come across. They sit still and wait for prey to appear, then pounce with their powerful legs. They eat beetles, ants, flies, worms, smaller frogs, including their own species, and even baby birds and garter snakes. Northern leopard frogs are preyed upon by many different animals such as foxes, snakes, raccoons, other frogs and even humans. They do not produce distasteful or poisonous skin secretions like many species of frogs and instead rely on speed to evade predation.
At Little Cataraqui Creek Conservation Area as well as other Conservation Areas in the region, these frogs can be found close to ponds, streams, marshes, reservoirs and lakes. They can also be spotted in fields or heavily forested areas, especially if there are streams nearby. To track them down, it is best to listen for a short snore-like call during spring and early summer. This is the sound of the male frog looking for a mate as breeding season is the springtime.
While the numbers of Northern leopard frogs have significantly declined over the past few decades, this species is not yet considered at risk in Ontario. If you want to help them recover, please be sure that you do not mow your lawn short, or perhaps at all in the late summer, especially near waterfronts. Help support a healthy population of crickets in your garden in August.
There are a number of environmental groups that have frog watch programs aimed at improving the native habitats of frogs in Ontario. If you would like to get involved or receive more information, please visit Frog Watch at naturewatch.ca or the Canadian Amphibian and Reptile Conservation Network at www.carcnet.ca