The Pro Natura environment group said female beavers usually give birth from late May to early July, and the babies or “kits” are extremely vulnerable to predation from dogs or foxes.
The group issued a call on Thursday for care to be taken in beaver habitat, in rivers and streams of the Swiss plateau, central Switzerland and eastern parts of the country.
While their parents weigh 150 to 20 kilograms, the kits are little fur balls weighing less than 500 grams, Pro Natura said.
They are incapable of diving in water like adults and as a result they make easy prey for predators, Pro Natura said.
European beavers were hunted to extinction more than 100 years ago but were reintroduced to Switzerland in the late 1950s and can now be found from the canton of Geneva, in the west, to Schaffhausen, in the northeast.
Now there are a few hundred beaver families, with couples that propagate every year, producing one or two kits on average per year, many of which do not survive, Pro Natura said.
But the group noted that the species is not as vigorous as the Canadian beaver when it comes to breeding.
“Give the low reproductive rate, it is therefore very important to protect this native mammal, which is very important for biodiversity.”
By buildings dams, beavers create calm and deep water areas for their offspring.
This has led to conflicts with farmers, particularly in the canton of Bern, where pastures have been flooded.
But Pro Natura said the rodents create habitat that benefits plants and other animal species such as the grayling and the kingfisher, among other species.
The group launched a “Hello Beaver” project in the canton of Basel-Country in 2000 to make areas, such as those near power stations, more beaver friendly.
The project became a national endeavour seven years later, covering western Switzerland, the central plateau and central an eastern Switzerland.
It offers counselling, education and publicity aimed at ensuring that the “return of the beaver continues to gain acceptance in our watercourses".