From what I saw in my 'Birds of Oregon' book, I concluded that this bird could very well be a female red-wing blackbird. It was with a male red-wing, and they were chirping to each other.

Here is what is said at 'All About Birds' about the female red-wing blackbird: "Females are a subdued, streaky brown, almost like a large, dark sparrow. In the North, their early arrival and tumbling song are happy indications of the return of spring." -
https://www.allaboutbirds.org/guide/Red-winged_Blackbird/id

Another link showing the female red-winged blackbird is here - http://tinyurl.com/h6pugqr