This trend has alarmed scientists.
In California, environmentalists are concerned about the decline in the population of butterfly species monarch, 2017, their number has decreased by 86%.
At last count, the non-profit environmental organization in California it was less than 30 thousand butterflies, which is 86% less than in 2017. For comparison, in 1981 the population numbered more than one million monarchs Monarch.
Environmentalists annually estimates to track the number of butterflies. A recent report says that there is no evidence of delayed migration. In other parts of the country, the monarchs were also not detected. A study conducted in 2017 at the University of Washington, showed that in the coming decades, the species will completely disappear, if mankind will not do anything to save it.
The monarch is one of the most well-known butterflies in North America, which attracts tourists wanting to take photos of interesting fauna of the United States. It is easily recognized by the characteristic pattern of black stripes on a reddish background.