Can't identify this guy

[Berkshire484]

Only seen twice. 14 and 15 May roughly around 2:30 pm. Unfortunately all I had at the time was my cell. About the size of a Robin or a bit smaller but not much. Yellow beak, some color on the underbelly between the legs and tail. Yellow legs. When it flew it had solid white wing tips. It flew away from me so that was all I could see. The tail fanned out similar to a hawk tail and other then the bright white wing tips the back was a solid black. Seen in the state of Washington, 26 miles from Mt. Rainier. I think the bird on the post was the female version but so far I have no clue e. 

[Melierax]

Evening Grosbeaks! Male and female. It's an irruption year so there are lots of them around.