The Birds Know that Fall is Here

 There are a number of humans that don't believe that summer will ever end.  

But the birds know that fall is here.

Last night, the weather radar showed an explosion of radar returns over land around sunset.  Many birds prefer to fly after sunset---safer that way.

Here is a composite of several radar sites at 7:30 PM last night (Tuesday) before the sun set.  Not much to see.


And here is the image at 10 PM.   Wow...lots of birds.  You notice they don't like to fly offshore!  


Modern Doppler radars provide wind velocity (actually the velocity of targets like precipitation) towards or away from the radar.  But last night there was no precipitation but plenty of birds.  And radar really picks up birds...they appear like giant raindrops.

Here is the velocity towards or away from the Langley Hill radar near Hoquiam.  Green indicates approaching birds and yellow/orange birds moving away.  These birds are moving south!

the weather radar showed an explosion of radar returns over land around sunset The Birds Know that Fall is Here


There is a very good website that shows bird migration based on radar imagery:  Birdcast.info.
Their graph for 11 PM last night shows the southward migration over our region.  But there was even more birds flying south across the eastern U.S.


Interestingly, there seemed to be far fewer birds flying around on Saturday night after sunset (see below at 11 PM).  Perhaps our feathered friends do not like smoke.  In fact, there are some studies that suggest this kind of avoidance.


Fortunately, I have some good news for migrating birds: by Friday at 4 PM, the region should be pretty much smoke-free according to the NOAA HRRR smoke model (see below).  So both humans and birds will be able to take a deep breath....

the weather radar showed an explosion of radar returns over land around sunset The Birds Know that Fall is Here


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