published: March 5, 2020
last updated: June 5, 2020
My first experience with the migration of painted lady butterflies (Vanessa cardui) was in the spring of 2019. It was Thursday, March 14th, and I'd been in the lab most of the morning emerging for sustenance around lunchtime.
While standing at the 2nd floor window looking out on the world, something caught my eye below drifting about 5 feet from the ground.
My mind registered leaves blowing on the wind and immediately challenged itself. It's spring, not fall, and whatever that is isn't moving quite like leaves on the breeze. I realized I was looking at a stream of butterflies and went outside to get a better look.
2019 was a pretty well celebrated migration year for the painted lady butterflies here in California. The great news is that regardless of where you live in the United States, you don't have to travel far to see these awe inspiring creatures. These beauties live almost everywhere in the world.
Where to see the Painted Lady butterfly
You won't find them in Australia or Antarctica, but the lovely Painted Lady butterfly can be found on every other continent and are quite plentiful in North America, especially when wildflower blooms are abundant.
Life cycle of the Painted Lady
Like other butterflies, the Painted Lady goes through several changes over the course of her life span. The egg stage typically lasts from four days to two weeks (I know, talk about a range!) before a caterpillar emerges.This caterpillar stage, also called the larval stage, lasts between two and four weeks before the caterpillar wraps itself in a silken cocoon and survives in the chrysalis for one to two weeks.
Once the Painted Lady butterfly emerges from her cozy cocoon, she may live up to 20 days.
How to be sure you're seeing a Painted Lady
Once in the butterfly stage, the Painted Lady lives up to her name with colorful brown, black, and rosy-orange wings that feature a prominent white bar and spots of white. The undersides of her wings are less elaborate with muted tones of gray and brown. The total wingspan of the Painted Lady is typically between two and three inches.
When at rest, the Painted Lady's folded hind wings show small white-bordered eye spots that distinguish it from the monarch and other brush-footed butterflies. Her hind wings may also boast eye spots that are blue or yellow. Similar black eye spots on the upper rim of the fore wings are typically surrounded with a ring of dark pink or red.
The caterpillar of the Painted Lady is somewhat more difficult to identify, mostly due to the fact that it goes through several instars, or developmental stages before making its astonishing transformation from larva to butterfly.
When it emerges from its faintly green egg, the caterpillar looks very much like a worm with a pale gray body and bulbous head. As the caterpillar matures, it develops observable spines as its body becomes mottled with traces of orange and white. Shortly before constructing the silken chrysalis in which it develops its wings, the caterpillar's color pales considerably.
Favorite flowers of the Painted Lady
When the Painted Lady is a caterpillar, she prefers wild thistles over any other food source. In fact, the creature is called the thistle butterfly in some parts of the country, due to its preference for such flowers. Adult Painted Ladies also enjoy the nectar of thistles and tend to lay their eggs on them, explains the San Francisco Gate.
If thistles are not available, the Painted Lady caterpillar will happily dine on asters, daisies, milkweed, and black-eyed Susans. The beautiful butterfly does not limit herself to these flowers, however. In a pinch, she may daintily sip nectar from more than 300 types of blossoms.
Best time and place to see Painted Ladies in migration
Unlike the famed monarch butterfly that makes a regular annual migration from northern Mexico to places like Muir Beach and Muir Woods in northern California, the impetuous Painted Lady doesn't migrate on any sort of set schedule.
Instead, Vanessa cardui is known to entomologists as an 'irruptive migrant' which means that the butterfly may move from one region to another with no regard to season or geography. In warm locations (think tropical), you're likely to chance upon the Painted Lady any time of the year.
In cooler climes, the pretty flier is found in the spring and summer. Migration tends to depend on weather and availability of food sources, and because the butterfly's lifespan is so short, it normally takes several generations of butterflies to make the full migratory trip from their winter grounds in Mexico and Texas all the way up to the Pacific Northwest and even Canada.
In California, one wave of migrants may travel from the southern deserts to as far north as the San Francisco Bay Area before they stop to breed. Once a new generation is born, younger Painted Ladies continue the migration further north.
In the American south, Painted Lady butterflies have a tendency to migrate northward as weather permits.
Massive painted lady butterfly migration
2005 saw what may have been the most massive migration of Painted Ladies in modern history, according to University of California at Davis professor, Arthur Shapiro. The professor told the New York Times that exceptionally high amounts of winter rain are to credit for that year's stunning show of migrating butterflies.
2005 produced a bumper crop of butterflies but that doesn't mean the show is over. In fact, Professor Shapiro revealed, the entire North American population of Painted Ladies migrates each and every year, and 2019 was also a huge migration year.
Painted Lady Butterfly Facts
- On overcast days, Painted Ladies may hide in holes in the ground
- Painted Ladies can travel more than 100 miles per day
- No butterfly is more widely distributed than the Painted Lady
- Also goes by the name thistle butterfly and cosmopolitan butterfly
- El Niño weather patterns may influence migratory behavior
- A single migration may comprise billions of Painted Lady butterflies
- A Painted Lady can attain speeds of up to 30 miles per hour
- Painted Lady caterpillars construct tents of silk
- Painted Ladies die when the weather gets cold
- Like all butterflies, the Painted Lady tastes with her feet
If you chance upon a migration of Painted Ladies, your heart might just skip a beat. I know this was my experience. I did not truly believe anything so magical could happen in a concrete city. But, as so often with nature, I was shown that beauty prevails even among man-made industrial buildings and asphalt.
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About the Author
Brandy Searcy is an outdoor girl who loves hiking, gardening, bird-watching, and body boarding. Her innate curiosity means she's constantly researching something, and she's likely sharing what she's learned here on the blog.
Nearly obsessive about her skincare, she started developing products to pack with her on day hikes and soon realized her backpacking friends were searching for a portable skincare routine as well, and that's how Rain Organica started.
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