Lassen Volcanic National Park has one species that is currently listed as Threatened under the Endangered Species Act (bald eagle) and one that was taken off the endangered species list in 1999 (peregrine falcon). Lassen Volcanic National Park is also home to a variety of invertebrate species which can be found in all of the habitats listed above. One of the most noticeable species is the California Tortoise Shell butterfly. These butterflies are orange-brown in color and can be seen by the thousands at times especially on the tops of peaks where wind currents have carried them. These population explosions are believed to be movements from areas that have been defoliated to new areas in search of a food source. These mass movements can make driving conditions hazardous due to slick pavement and windshields becoming plastered with dead butterflies.