Another thing that seems weird to me is that they were all Red-Winged Blackbirds. Male and female. I didn't see any other species in the news reports. Were there others?
Most irregular.
I suspect this was the MILE WIDE FLYING SAUCER earlier seen in Texas just shortly before the optical illusion off the coast of LA.
Think of it this way ~ space aliens with a massive craft use a variety of deceptive imagery to hide it from our sight, or make it invisible.
The flaw is that if it's invisible to migrating birds they'll run into it. The fish are probably triggered by an otherwise undetectible sonic whine from the spindizzy generators. James Blish would know and get all excited about this but he's been gone from this mortal coil for 35.5 years (almost to the day).