Alien Alert!

Following up to the work we did last year, Okanagan Similkameen Stewardship representatives are coming to a pond near you.  With unconfirmed reports of Invasive American Bullfrogs in Penticton and Summerland, OSS staff will be surveying day and night for these frogs.


If you live next to a pond or oxbow or frequently walk nearby, become a citizen scientist volunteer! Learn how to identify and report invasive bullfrogs!  Contact us at to find out how you can become a citizen scientist!

Listen to their call and let us know if you've heard them! CLICK HERE TO HEAR THEIR CALL.

Introduced American Bullfrogs pose a great threat to
local amphibian populations.
Photo: Alyson Skinner
Bullfrogs were originally introduced in the 1950s close to the Canada-US border in the South Okanagan. Researchers, private landowners, local conservation organizations, and government have collaborated in bullfrog removal efforts in the South Okanagan since 2004. Removal efforts have drastically reduced bullfrog occurrence near the Canada-US border; however, a handful of bullfrogs can colonize an area within 1 or 2 breeding seasons. Detecting all individuals is essential in preventing the species’ spread.
Graphic: BCFrogwatch

Introduced bullfrogs pose a great threat to our native Okanagan amphibians. Massive compared to our native amphibians, bullfrogs are not only voracious predators, but they reproduce rapidly by laying thousands of eggs, outcompete other animals for resources, and spread disease to native amphibians. Many of our native amphibian species are already at risk due to human influences such as habitat loss, road mortality, and pollution. Removing the added threat of bullfrogs is vital to native amphibians’ survival in the Okanagan. Bullfrogs take up to 2 seasons to mature into adults, putting permanent ponds and the species which live in permanent ponds, such as the endangered Blotched Tiger Salamander, at particular risk.

American Bullfrogs are olive/yellow in colour
with a greyish belly and are MUCH larger than
native amphibians.
Photo: Deddeda
Identifying Characteristics of introduced American Bullfrog
  • Largest of North American frogs, measuring up to 20cm long- MUCH larger than our native amphibians.
  • Olive/yellow with a grey belly
  • Males have bright yellow throats during mating season
  • Prominent ear drums (tympanic membranes) with skin fold wrapped around the ear drum with ridges down the back
  • Adult males have a distinctive call that can be heard over spring through August. CLICK HERE TO HEAR THEIR CALL.

If you think you have seen or heard a bullfrog, please do not capture the individual, but report your sighting to BCFrogwatch, at, or OSS at

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