Colorado HairstreakHypaurotis crysalus
Quick facts
- Rarity
- Uncommon
- Active during
- Afternoon
- Found in
- Strawbend Fields
- Length
- 1.5 in
- Wingspan
- 1.4 in
From the field notes
Diet
Caterpillars are extremely picky eaters, almost exclusively consuming the tender, new leaves of Gambel oak. This narrow preference means that if there are no oak trees, there are no hairstreaks.
Defense
Those delicate, thread-like tails on their hindwings act as a clever decoy. When resting, the butterfly rubs its wings together to make the tails twitch like antennae, tricking hungry birds into snapping at the wrong end.
Migration
These homebodies stay loyal to their favorite oak groves year-round. Instead of migrating south for the winter, they endure the mountain snow as tiny, frost-resistant eggs glued firmly to bare twigs.
Lekking Behavior
In the late afternoon, males gather in sunlit Gambel oak tree tops, aggressively defending temporary territories while they wait for females. The gathering of males like this is known as lekking.
Field Marks
Their defining feature is the flash of iridescent purple, dark borders, and bright orange spots visible when their wings are open. When their wings are closed, they instantly camouflage against bark.