What species is this lizard?
Thank you for your question. Your photo is somewhat out of focus when I try to enlarge it and the gloved hand is covering up areas that would be useful in making an identification, but I believe this is a Northern Alligator Lizard (Elgaria coerulea). This species has a distinct fold of skin on each side of its body that separates the keeled dorsal (back and sides) scales from the smooth ventral (stomach) scales, but I can't see if this is present due to the position of the lizard and the gloved hand. There is a Northern and Southern Alligator lizard, and you say this one was caught in northwestern Washington, and the southern species range does not extend to the northwestern part of the state.
This species is reportedly found in grassy, brushy or rocky open areas within forested areas. When handled this species can easily shed its tail, and it appears from your photograph that this individual has lost its tail at one time.
They feed on insects, ticks, spiders, millipedes and snails.
Here's a link to the Washington Herp Atlas page for this species:
Hope this answers your question, and thanks for using Ask an Expert.