Nearly 400 endangered northern leopard frogs raised at Northwest Trek Wildlife Park are now back in the wild at the Columbia National Wildlife Refuge in Grant County.  For four years, Northwest Trek has received northern leopard frog egg masses in the spring from the one remaining wild population at the Potholes Reservoir, collected by Washington Department of Fish and Wildlife (WDFW) biologists. Keepers at Northwest Trek then raise the frogs in a controlled environment, monitoring the overall condition of their tanks, including water temperature, pH levels, good bacteria, nitrogen cycle, and oxygen levels. They also protect the frogs from …