What kind of pollution is killing hummingbirds?

Hummingbirds are primarily threatened by pesticide pollution, particularly neonicotinoids, which are widely used in agriculture. These chemicals can harm birds directly or indirectly by reducing their food sources, such as nectar-producing flowers and insects. Additionally, habitat loss due to urbanization and climate change compounds the effects of pesticide exposure, further endangering hummingbird populations. Overall, the combination of toxic chemicals and environmental degradation poses a significant risk to these delicate birds.