What isn't disturbing?

What impact do we have, as birders, as we walk trails in parks and reserves and other places we look birds?

A study in New York state concluded that disturbance from recreational use — noise and motion — of such land had "at least temporary effects on behavior and movement of birds."

The study concluded:

Children and photographers were especially disturbing to birds.

Direct approaches caused greater disturbance than tangential approaches.

Rapid movement by joggers was more disturbing than slower hikers.

Passing or stopping vehicles were less disturbing than people on foot.

Road noise negatively affects birds (reduced nesting, etc.) at distances of up to 1,000 meters, so noise from trail users might also affect birds but presumably over shorter distances.