To bring a bit of hope, things can revert quite quickly too.
I’ve seen a study on a farmer who stopped using pesticide and started using permanent ground cover plants with their crops. In a year the amount of insect biodiversity at ground level was crazy. From almost zero to almost normal. There is no doubt that birds will quickly follow.
Food chain collapse starts at the bottom, with the tiny things, then the small things.
What comes after birds?
The article seems to focus mainly on “backyard” birds that eat seeds, insects, etc. so predatory birds (like hawks, owls, etc), foxes, snakes, coyotes will probably take a hit. The populations of other things the predators eat will also be stressed since they will be hunted and consumed more frequently when there is less variety.
