Western Sulphur
Colias occidentalis Scudder, 1862
Family: Pieridae
Subfamily: Coliadinae
Identification: Upperside of male bright yellow with wide black border; orange morph is orange with yellow at costa and wing bases. Female pale yellow to greenish white with border blurry, incomplete, or absent; orange morph dull orange with wide black borders and dark veins. Underside of both sexes with pink wing fringes and golden yellow hindwing; orange morph green-gray to orange; both with dark overscales.
Wing Span: 1 3/4 - 2 1/2 inches (4.5 - 6.3 cm).
Life History: Males patrol in valleys or open areas near host plants for females. Females lay eggs singly on host plant leaves. Late-stage caterpillars hibernate.
Flight: May-August, mainly June-July.
Caterpillar Hosts: Plants of the pea family (Fabaceae) including vetch (Vicia angustifolia), sweet vetch (Hedysarum), lupines (Lupinus), and white sweet clover (Melilotus alba).
Adult Food: Flower nectar.
Habitat: Open areas including meadows, sagebrush flats, conifer forest openings, power-line cuts.
Range: Extreme southern British Columbia and northwestern United States south to north coastal California and central Utah.
Conservation: Some populations affected by grazing and fire suppression.
NCGR: G3, G4 - Very rare or local throughout its range or found locally in a restricted range OR Apparently secure globally, though it might be quite rare in parts of its range, especially at the periphery. Subspecies chrysomelas is T2,T3 and is threatened by fire suppression, improper logging, and invasive alien weeds.
Management Needs: Not reported.
Comments: NULL
Get your BAMONA Gear!
Please donate!
We depend on donations to keep Butterflies and Moths of North America freely available. We want to express our gratitude to all who showed their support by making a contribution this year. You can donate to support this project at any time.
Advertise with us!
Do you have a product or service that you think would interest BAMONA users? If you would like to advertise on this website, contact us by email, or use the contact form and select the "Advertising" category.
Verified Sightings
Displaying 1 - 24 of 161 verified sightings
Observation date: Jul 27, 2023
Submitted by: Amanda and Graham
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Jul 28, 2023
Observation date: Jun 24, 2023
Submitted by: hiker96
Region: Yakima County, Washington, United States
Verified by: davidwdroppers
Verified date: Jun 25, 2023
Observation date: Aug 04, 2019
Submitted by: Claire Christensen
Region: British Columbia, Canada
Verified by: Paul Prappas
Verified date: Sep 14, 2022
Observation date: Aug 20, 2022
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Aug 25, 2022
Observation date: Jul 17, 2022
Submitted by: Thom Garrett
Region: Missoula County, Montana, United States
Verified by: J_Martineau
Verified date: Aug 24, 2022
Observation date: Jul 30, 2022
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Aug 04, 2022
Observation date: May 15, 2020
Submitted by: Birder2
Region: Sherman County, Oregon, United States
Verified by: James Steen
Verified date: Aug 04, 2022
Observation date: Jun 23, 2022
Submitted by: weflybye
Region: Klickitat County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 28, 2022
Observation date: Jun 18, 2018
Submitted by: Mark Salvato
Region: Jackson County, Oregon, United States
Verified by: Ken Davenport
Verified date: Oct 19, 2021
Observation date: Jun 15, 2018
Submitted by: Mark Salvato
Region: Jackson County, Oregon, United States
Verified by: Ken Davenport
Verified date: Oct 19, 2021
Observation date: Jul 14, 2021
Submitted by: glennfine
Region: Siskiyou County, California, United States
Verified by: Ken Davenport
Verified date: Aug 22, 2021
Observation date: Jul 18, 2021
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 19, 2021
Observation date: Jul 10, 2021
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 14, 2021
Observation date: Jul 13, 2021
Submitted by: hiker96
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 14, 2021
Observation date: Jul 13, 2021
Submitted by: Artemisia
Region: Clallam County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 14, 2021
Observation date: Jul 22, 2018
Submitted by: Chris Carvalho
Region: Hood River County, Oregon, United States
Verified by: davidwdroppers
Verified date: May 09, 2021
Observation date: Jul 14, 2019
Submitted by: cgates326
Region: Crook County, Oregon, United States
Verified by: davidwdroppers
Verified date: May 09, 2021
Observation date: Jul 23, 2017
Submitted by: Chris Carvalho
Region: Hood River County, Oregon, United States
Verified by: davidwdroppers
Verified date: May 09, 2021
Observation date: Jul 22, 2020
Submitted by: gasigr
Region: Wallowa County, Oregon, United States
Verified by: Ken Davenport
Verified date: Mar 16, 2021
Observation date: Aug 02, 2020
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Aug 03, 2020
Observation date: Jun 04, 2020
Submitted by: icosahedron
Region: Sonoma County, California, United States
Verified by: Ken Davenport
Verified date: Jun 06, 2020
Observation date: Jun 04, 2020
Submitted by: icosahedron
Region: Mendocino County, California, United States
Verified by: Ken Davenport
Verified date: Jun 06, 2020
Observation date: Jul 26, 2019
Submitted by: PDunwiddie
Region: Morrow County, Oregon, United States
Verified by: Ken Davenport
Verified date: Aug 15, 2019
Observation date: Jul 21, 2019
Submitted by: weflybye
Region: Mason County, Washington, United States
Verified by: davidwdroppers
Verified date: Jul 21, 2019
- 1 of 7
- next ›