Migration in the Pacific Northwest

Since I'm located east of the Great Plains most of my focus on birds is the eastern half of the U.S. but I did look at some radar images this morning from the Pacific Northwest and there looks to be a pretty good landing on migrants from Portland, OR to Vancouver, BC. Below are images from this morning:

 

 The top image above shows migrants arriving this morning and as time progresses the image returns become more faint as birds land. This is the exact opposite progression of the liftoff we see in the evening.

 Ann Nightingale of Victoria, B.C. mentioned on BIRDBAND another radar image source for that region that looks really good. It is from the University of Washington. Again, the top image shows birds arriving and the second shows the image fading as birds land. For west coast birders I've also seen this pattern in the central valley of California.

 Here are those images:

 So as spring migration really begins to peak it might be worthwhile for birders to look at weather to get a feel for movement both into and out of your region. The thing that I've learned is that a good migration movement sometimes means birds are leaving - not arriving.

I'm going to go watch the White-throated Sparrows under my feeder for a while...