People often forget that the vast majority of birds feed grubs, worms, maggots, and various insects to their young until they are old enough to be fledged.
There are however also many solitary bees, such as leaf cutter, mason, and carpenter bees that are drawn to the flowers too. All of these bees are sensitive to pesticide residues to a lesser or greater degree.
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Bugs Eating Your Sunflower Leaves- Sunflowers Pest and Problems