Sara's Orange-tip, Western Orange Tip, Pacific Orangetip, Anthocharis sara
Sara's Orange tip is a highly varied butterfly that ranges from Northern Mexico, New Mexico, across to California and up to Whitehorse in the Southern Yukon.
Host plants include all sorts of mustards. So Orange Tips are common in most areas where man has been.
A Sara Orange Tip on a Filaree flower. They will take nectar from most any small to medium flower. Do not plant filaree for these butterflies, plant something that's not a weed.
This is a spring version of Western Orange Tip is called Reakit's.