Lydia,

There are two species of gartersnakes found in your area -
common gartersnake, Thamnophis sirtalis (subspecies
Puget Sound garter, T. s. pickeringi), and northwestern
gartersnake, T. ordinoides. Both are extremely variable,
and both can exhibit blue-ish stripes. Generally, headsize
in sirtalis is larger and scale counts vary somewhat.
Otherwise, they can be difficult to differentiate in the field.
The wandering gartersnake, T. elegans vagrans, is occasionally
found in the Puget Sound region, but usually lacks
prominent dorsal striping.

>Hi Tweeties!
>
>While out on a walk along the Green River last night I discovered a kitten
>having the time of its life playing with a recently dead snake (It was
still
>floppy). It looked like a garter snake, but rather than having tan and
red
>stripes, its stripes were pale blue. The snake was quite small, less than
a
>foot in length and quite slender. Anybody out there with some snake
>expertise?
>
>Thanks,
>
>Lydia In Kent, WA
>Lydia Gaebe
>lgaebe at msn.com
>