Based on 2,346 research-grade iNaturalist observations in Washington, California Scrub-Jay is most often recorded in May; in Washington it behaves like a year-round resident. It ranks #64 among birds recorded in the state in our data.
Aphelocoma californica
California Scrub-Jay in Washington by month
Bars show research-grade observations per month. They mix true seasonality with how often people are outdoors, so treat small numbers with caution.
Also seen in Washington in May

Mallard

American Robin
Canada Goose

Great Blue Heron

Dark-eyed Junco

Song Sparrow
Red-winged Blackbird

Bald Eagle
Places to look in Washington
Gifford Pinchot National Forest
Olympic National Forest
Peace Arch Park
Colville National Forest
Mount Baker–Snoqualmie National Forest
Bellevue Botanical Garden
FAQ
When does California Scrub-Jay appear in Washington?
Mainly April–March, with the most records in May.
How common is California Scrub-Jay in Washington?
It ranks #64 by number of iNaturalist observations among birds in Washington (2,346 records in our sample).