Gray hairstreak vs Eastern tailed-blue

These two are easy to mix up. Here's how to tell a gray hairstreak from an eastern tailed-blue, and whether either one bites or stings.

≠The key differences

Usually brighter blue on the upperside (males), smaller, and lacks the pronounced orange hindwing patch seen in gray hairstreaks

	Gray hairstreak	Eastern tailed-blue
To humans	Non-toxic	Non-toxic
Size	25-35 mm wingspan	Wingspan 18-30 mm
Colours	Pale gray, Orange, Black, White	Sky blue, Warm brown, Pale gray, Orange
Family	Lycaenidae	Lycaenidae
Habitat	Open, sunny habitats: fields, meadows, roadsides, gardens, parks and disturbed areas	Open, sunny places: fields, meadows, roadsides, lawns, gardens, and disturbed sites
Range	Widespread across most of North America from southern Canada through the United States into Mexico and parts of Central America	Widespread across eastern and central North America: from eastern Canada south through the eastern and central United States and into parts of Mexico. Less common or replaced by similar species in far western North America.
Active	Spring through fall (year-round in some warm regions); active during daylight, especially late morning to afternoon	Spring through fall (earliest broods in spring, continuing into autumn); active during daylight, especially in sunny conditions
Pest?	No	No

Very small wingspan (about 18-30 mm) — noticeably smaller than many other common blues
Tiny tail-like projection on each hindwing plus an orange submarginal spot near the tail on the underside
Males bluish upperside with narrow dark border; females brownish with blue dusting
Underside pale gray with small dark spots; check hindwing for the orange spot and short tail

Usually brighter blue on the upperside (males), smaller, and lacks the pronounced orange hindwing patch seen in gray hairstreaks

Gray hairstreak: Non-toxic. Eastern tailed-blue: Non-toxic. Harmless to people. Eastern tailed-blues do not bite or sting and are harmless to people.

Identification from photos is never certain: don't handle insects you can't identify, and get medical advice for bites, stings or allergic reactions.