In Sweden you can find edible frogs Pelophylax kl esculentus in the southern county Skåne, where this hybrid lives separate in good numbers as diploid and triploid frogs. North of Stockholm in Uppland we find the pool frogs Pelophylax lessonae, well separated geographically from other Swedish green frogs. Some of those northern pool frogs were exported to England in 2005.
The 700 km area in between Skåne and Uppland there were earlier a few old localities fairly close to the Baltic coast. The last remaining natural population in this area is located at Hannäs in Östergötland county at 58 09 N, a place which I visited last week. In the forest pond Lindalsgölen above the village you can still find at least 50 adult frogs today. Although this small population was discovered as late as 2004, green frogs of an undefined sort had been observered in the nearby lake Vindommen since 1975. The Lindalsgölen frogs were genetically examined in 2004 by two Swiss scientists which concluded that the population was a lessonae/esculentus system, a former unknown system in Sweden.
Today the frogs are most easily observed in the pond in June, when the males are croaking. But I was also lucky to find a female in a new pond near the lake, where the frogs lives much more undetected.