During nesting season, birds don't have the option of freely approaching and freely departing.
If you approach a nest, you are moving into their space and creating intense stress.
I'm discouraged by how many #birders—who should know better—ignore this. We, of all people, have to do better.
Below, a fledgling Anna's hummingbird that left the nest only hours before. My shots were taken with an 800mm lens from a distant concealed location.
But then other birders arrived, standing 2 meters away from the bird, using loud mechanical shutters. The mother panicked and stopped feeding.
I protested. One argued "they eat from my hand in my yard!" and stepped back to 3 meters. Useless.
#Photographers, respect your subjects. Learn their behavior. Your shots are not worth a bird's life.