True but thought I'd read that the new ones were OK for them....can't find it now.It's worse for the birds because they can detect the flicker even better than humans.
Old tubes went 60 cycles per second......new ones between 10,000 and 40,000 cycles per second.
Too fast for our eye...but not sure about birds.
CFL I used didn't drive my birds nuts so.....<shrugs>