Green is on our minds at Stillwaters, not just because it’s spring, but because of two non-native species that become part of our monitoring efforts this time of year: the Green Frog and the European Green Crab. This week, we want to tell you about the Green Frog and thank Eir and Niki Quester for several new photos they sent last month of healthy adult frogs at the stormwater pond off of Tuckerman Rd (near our Stream monitoring Site #2).
The Green Frog (Lithobates clamitans) is native to eastern North America but has introduced populations in B.C. and Whatcom County. Last spring, WDFW biologist Marc Hayes visited Stillwaters and confirmed that these non-natives had arrived in Kitsap: specifically, in Carpenter Lake and ponds and wetlands along Barber Cut Off Road.
Unlike the Bullfrog, the Green Frog’s impact on PNW ecosystems is not well understood. Native amphibians in Kitsap breed most successfully in temporary wetlands during winter and early spring, while Green Frogs and Bullfrogs delay breeding until water temperatures are much warmer and are thus most successful in water bodies that don’t dry up in the summer.
How to Identify a Green Frog
Green Frogs and Bullfrogs can be distinguished from our native Pacific Tree Frogs and Red-legged Frogs both by prominent ear drums readily visible behind their eyes—larger than the eye in males, smaller in females (in native frogs the ear drums are smaller and obscured by a dark ‘mask’). Green Frog calls are also very distinctive and have been described as a “banjo twang.” To hear recordings of all these frogs’ calls and learn about features distinguishing Green Frogs from Bullfrogs visit Whatcom County’s Amphibian Monitoring Program website: https://whatfrogs.wordpress.com/ and check out their ‘Species Facts’ and ‘Chasing Invasives’ pages.
You can help by reporting Green Frogs!
If you think you’ve seen or heard Green Frogs (or Bullfrogs for that matter) this spring please let us know where and when by calling Stillwaters (360-297-1226) or e-mailing Melissa (firstname.lastname@example.org). Tom Doty, an amphibian biologist and North Kitsap Heritage Park steward, discovered Green Frogs in the Park this spring and is interested in teaming up with Stillwaters to monitor the health of local native amphibian populations and identify any impacts of Green Frogs on native species. Our primary goal is to first identify how far this non-native has spread in the area. Secondarily, we are exploring the possibility of conducting a more formal study of local amphibians (if there is a willing landowner with an appropriate pond and we can find a graduate student or other volunteers to participate!).