A few years ago the Nicola Naturalist Society posted a wonderful series of articles and resources about some of the butterflies in the Thompson Okanagan area which you should definitely check out.
I thought it would be fun to post a quick list of what they deem the butterflies you are most likely to see in April.

Mourning Cloak
Wingspan – 5-10cm
Habitat – almost anywhere
Eats – mostly tree sap
Caterpillars eat – willow, cottonwood, aspen, paper birch
Source: Butterfliesandbmoths.org
Stella Orange Tip
Wingspan – 3.5-4.8cm
Habitat – deserts, open woods, orchards, waterways
Eats – flower nectar
Caterpillars eat – plants in the mustard family
Source: Butterfliesandbmoths.org
Satyr Comma
Wingspan – 4.5-6.4cm
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org

Green Comma
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org
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Spring Azure
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org

Compton’s Tortiseshell
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org
California Tortiseshell
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org

Milbert’s Tortiseshell
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org
Margined White
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org

Spring White
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org
Sheridan’s Green Hairstreak
Wingspan –
Habitat –
Eats –
Caterpillars eat –
Source: Butterfliesandbmoths.org