Updated: May 6, 2019
Southern California has been host to two remarkable spectacles this Spring, a super bloom of wildflowers and a massive migration of painted lady butterflies. According to data from the National Oceanic and Atmospheric Administration (NOAA), an El Niño weather pattern has been detected for 2019. This has caused an increase in rainfall to the usually dry desert regions of the United States and Mexico. As a result, wildflowers and other vegetation have covered many of the natural areas in California. The number of painted lady butterflies has likewise seen a dramatic uptick due to the weather event.
Painted ladies are small butterflies with a wingspan of only about two inches. They have been reported to fly at speeds up to 30 miles per hour and can cover close to 100 miles in a single day. In years when the winter has brought significant rain, their population tends to grow exponentially because of the abundance of plants that serve as a food source. This year millions have been recorded passing through the Southern California area as they migrate to the Pacific North West for the summer. During this migration period, the butterflies feed, mate and lay eggs among the wildflowers.
The sight of this huge migratory event has been exciting for residents and tourists in California. One Calabasas native hiking a local trail said, “They’re everywhere! I had to get out here to take some pictures.” She was visiting an area that had been completely destroyed by the Woolsey Fire this past November. An outbreak of black mustard wildflowers has taken over in the burn scar regions, growing in some places as high as ten feet. Although these plants are an invasive species, they are providing much needed food and habitat for the butterflies as they pass through.
Unfortunately, not all butterfly species are benefitting as much from the extreme weather. Monarch butterflies are an iconic species that have been recorded as being in a severe decline for several years now. There are a few different reasons that are believed to be contributing to this. The use of pesticides and land development have wiped out much of the milkweed plants that are critical for the reproduction of the monarchs. Another reason is climate change. In fact, butterflies are described as an indicator species that help biologists and other scientist understand the health of the environment. If butterflies begin to struggle, its very likely the rest of the ecosystem could be in trouble as well.
There are some ways people can help butterflies like painted ladies and monarchs. The National Wildlife Federation put out a list of ways to improve chances of survival for monarchs. This includes ideas such as avoiding use of pesticides, advocating for grassland protection, and planting flowers at home, especially milkweed.
The video below shows the painted lady migration taking place in Calabasas this spring.