Night herons are colonial herons of southern Europe that have bred occasionally in the UK and appear as vagrants, with welfare considerations around their vulnerable breeding colony ecology.
Night heron welfare at colonial nesting sites is challenged by disturbance events that affect all breeding pairs simultaneously. Human disturbance causing mass flight of a colony can abandon entire clutches simultaneously. Colonial nesting creates vulnerability to predators that locate nests by watching human disturbance and attacking during abandonment. In the UK, vagrant night herons face welfare challenges finding suitable habitat and food in unfamiliar environments. Range expansion birds attempting to establish breeding colonies in new areas face the welfare cost of investing in breeding attempts in unproven habitat. Wetland drainage and habitat loss in their main European breeding range threatens populations that contribute vagrant birds to the UK.