Monarch on a thistle
The Monarch is one of our most common butterflies in the Sierras and are especially common in Yosemite Valley where the larvae feed on the many milkweed plants. The plants toxins make them unpalatable to birds. These butterflies are found world wide but our population migrates to the Pacific Grove area each winter. Their populations are in decline due to the agricultural spraying of weeds which is killing a lot of the milkweed plants needed for the monarch's survival.