As far as I’m concerned, DDT was harmless to everything other than insects.
But the “Silent Spring” problem may have been real because if you kill enough insects, the songbirds may go away to find a place that still has insects. The birds are dead, they just relocate. But the environmentalists will panic.
Any really effective insecticide seems like to have a similar effect.
Sheesh! I meant to say “the birds AREN’T dead”.