you brought back a memory;
my mother watched me take my shotgun under our two big old elm trees that had about a million blackbirds roosting in them when I was about 12..... I fired up into the trees from underneath expecting the sky to turn black. that's when I learned what birds do when they are startled. While there were many birds that fell, the sky turned white instead of black, and my mom laughed until she couldn't stand up..... for years she would take her finger and point up and go bang and bust out laughing.
she also wouldn't let me in the house until I used the outside hose to get the white off.... never startle a bird while standing under it....... and especially about a million blackbirds.... unless you're trying to entertain your mother.
Now, this was great!