In addition to wonderful migration "funnels" and migrant traps, the east coast has mostly deciduous trees that do not leaf out until after the spring migration. The birds are therefore much easier to see. Western Washington, on the other hand, has year-round rain forest vegetation that effectively conceals the birds. Having spent many years birding in the Bosotn area, I find Washington passerines just too frustrating. Declining eyesight doesn't help.
Gene Bullock
Poulsbo