Many types of human activity can kill birds.
| Cause | Bird deaths per year (U.S.) |
|---|---|
| Feral and domestic cats | Hundreds of millions |
| Power lines | 130 million -- 174 million |
| Windows | 100 million -- 1 billion |
| Pesticides | 70 million |
| Automobiles | 60 million -- 80 million |
| Lighted towers | 40 million -- 50 million |
| Wind turbines | 10,000 -- 40,000 |