Human disturbance, both confirmed and suspected, accounted for 43% and 18% of all known nest failures, respectively. Confirmed human disturbances included: nest trees burned or cut down ( n = 3), poaching or intentional killing of eggs/nestlings ( n = 9), and abandonment due to excessive human activity such as rocks and sticks thrown at the nest ( n = 5). Suspected human disturbances included the disappearance from nests of older healthy nestlings during successive years at sites where landowners were openly known to persecute the hawks, or where people were suspected of poaching nestlings for food ( n = 8).