words: flappy birds, but real life

These birds have been visually identified as having tails. Science
prevails.

Updates tailscale/corp#9599

Signed-off-by: Charlotte Brandhorst-Satzkorn <charlotte@tailscale.com>

words/tails.txt

@@ -577,3 +577,8 @@ raven
 corvus
 mellori
 bat
+sapsucker
+woodpecker
+nuthatch
+flicker
+junco