When reaching for some seed to feed the birds at a friend's house in Salmon Creek, I noticed a small visitor in the bottom of the storage container.
Here's a close-up.
I think it's a Deer Mouse (Peromyscus maniculatus) — but correct me if I'm wrong!
I was curious about their noticeably long whiskers, or vibrissae, and how they might be used. Unfortunately, I couldn't find much information about mouse vibrissae.
So instead I searched for information about feeding in Deer Mice (How much bird seed had the mouse eaten? Or in this case, perhaps it should be called "mammal seed" rather than bird seed?).
It turns out that a study was published about the effects of extra food on small rodent populations such as Deer Mice (Taitt 1981). When given supplemental food, the mice decreased the sizes of their home ranges. They were also able to reproduce even in poor weather conditions (e.g., the extra food allowed them to override the effects of cold temperatures that normally would have delayed breeding). The author of this study suggested that Deer Mouse populations may be limited by seasonal food availability.
This was just one mouse and a brief adventure in a bird seed container. I don't think it will change the Deer Mouse population in Salmon Creek, but it probably made for a satisfied mouse!