What are all of these orange butterflies?

Apr 25, 2019
Have you noticed a large number of orange butterflies recently? Read on to learn what they are!

by Jana Hemphill

What are all of those orange butterflies flying around town? There’s so many of them!

If you have said that in the past couple of weeks, I am right there with you. Every time I go for a hike, I see dozens upon dozens of these orange butterflies. So what are they and why are there hundreds of them everywhere?

California Tortoiseshells have slightly tattered wings in the spring. Photo: Land Trust.
California Tortoiseshells have slightly tattered wings in the spring. Photo: Land Trust.
Most likely you are seeing the California Tortoiseshell (Nymphalis californica). These orange beauties overwinter in Central Oregon as adults, which is why we see them in the early spring. This is also the reason they usually have tattered wings and look slightly faded. During the spring, they like to nectar on fir needles, so keep an eye out for them in fir trees as well.

To identify a California Tortoiseshell, look for an orange-dark brown-reddish tinge. They have rough lobes on their wings with a black border. They also have some large and small black spots.

California Tortoiseshells love snowbrush. In fact, they prefer to lay their eggs on this aromatic bush. Once these eggs hatch into caterpillars and are then transformed into adult butterflies, Central Oregon will have another surge of California Tortoiseshells flitting about in the later summer through early fall. Then, they will find good places to overwinter, like crevices in buildings, wood piles, and other shelters.

The dark underside of the California Tortoiseshell. Photo: Land Trust.
The dark underside of the California Tortoiseshell. Photo: Land Trust.
Why are we seeing so many? California Tortoiseshells live on a boom and bust cycle. We will see thousands of them in a single year, then their numbers will crash, and we’ll hardly see any for the next several years. In recent years, however, California Tortoiseshells have peaked for several summers in a row. That means you should enjoy them this summer because we might not see them again for a few years.

What about monarchs? While it’s easy to confuse monarch butterflies with California Tortoiseshells, here’s one way to tell the difference in the spring: monarchs aren’t here! Western monarch butterflies overwinter in southern California, so they have not migrated back to Central Oregon by springtime. They typically arrive here between early June through early October, peaking in early July through late August.


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