Human disturbance of nesting birds causes nest abandonment and chick mortality, with timing and proximity determining whether interaction causes welfare harm.
Human disturbance of nesting birds causes direct welfare harm through nest failure — eggs chilled, chicks abandoned, predators attracted to disturbed sites. For rare species, nest failures have conservation implications beyond individual welfare. The welfare-positive approach to wildlife observation involves maintaining appropriate distances, limiting duration of observation, and being particularly vigilant during the most sensitive early incubation phase. Bird photography that forces close approaches or repeated visits to nesting sites causes measurable harm regardless of the quality of the images obtained.