Thanks to all who responded with book references and suggestions re species
and scenarios.

I'm down to American Crow and Stellar's Jay, both of which are present in the
park. My only current reference is Ralph Hoffman 1927, in which he describes
the background color of both as "greenish". I will check out the suggested
references and report back.

The eggshell was gone when I checked today. Darn, this is one time I wish I'd
been able to get past my "take nothing but pictures" mindset.

Catherine Alexander
Lakewood Neighborhood
South Seattle