top of page
Half-moon Hairstreak

Satyrium semiluna



Endangered (Federal)
Red List (Provincial)


Adult butterflies have a wingspan of approximately 3 cm (1.5 in). The top side of the wings are drab brown or blackish-brown. The undersides of the wings are grayish-brown featuring a few black spots, slightly edged with white scaling. Caterpillar larvae are light green with jagged whitish stripes and a dark brown head.

Adults fly from late May to early July. They are found in unforested Sagebrush/Bluebunch Wheatgrass habitat in the south Okanagan Valley between 600 and 1100 m elevation where Silky and Sulphur Lupine plants are present. Halfmon Hairstreaks may have a mutualistic relationship with certain ant species.


-Agricultural and urban development of habitat
-Invasive plants
-Intensive livestock grazing
-Fire suppression leading to forest encroachment and ingrowth

You Can Help!

-Protect and conserve wildlife habitat
-Control and/or remove invasive plants and reduce soil disturbance to prevent invasive plants from establishing
-Reduce livestock grazing
-Consult with professionals about developing and implementing a prescribed burn.


bottom of page