© Joe Krieg

Heil Valley Ranch, Boulder County

Appearance: Two tails on hindwing. Tiger stripes narrower than on W. Tiger. Often seen in high floating flight where two tails may not be distinguishable. Patrols stream courses looking for females. Males puddle where two tails are more likely to be seen.

Size: Large, 4-5 inches

Habitat: Foothills slopes and canyons, urban parks and gardens, valleys, streamsides, and woodlands.

Season: May to mid-August

Larval Foodplant: Cottonwood, ash and chokecherry

Did You Know...
This butterfly is our second largest, exceeded only by the rare (for this area) Giant Swallowtail. Should be seen where green ash shade trees line urban streets.