It was a Pacific Flyway party last night. Heavy migration from San Diego to Seattle. Birds definitely took advantage of the south winds associated with the leading edge of the incoming cold front.
I threw in a snapshot of the National Composite radar today for another look at the interaction of weather and migration. With a big storm front draped across the central part of the country it is easy to see migration out in front of it and nothing immediately behind it.
A few more Purple Martin reports in the Portland area but that’s about it. The big push is just around the corner as the Central Valley is loaded with migrants.
Excellent night flight, and as i write this it is still at full tilt.
Only new migrant reported that i saw listed was Purple Martin on the southern Oregon coast.
But tonight is one of those teachable moments on the interaction of the weather and migration. So we’ll look at the conditions at 850 mb heights — note the stream lines and the ridge in the west and the trough in the east. Then check out the static image of the national radar composite. (The full loop can be viewed over at Paul’s archive: here)
The Pacific Flyway from the Mexican border to the Canadian border is solid blue with birds. Everywhere else? Central and Mississippi Flyways — nada. Atlantic Flyway? — just a tiny bit on the SE coast ahead of the advancing cold front.