Effects of human approaches to nests of northern New Zealand dotterels

The northern New Zealand dotterel Charadrius obscurus aquilonius is an endangered shorebird, and it is thought that human disturbance may decrease its nesting success. We made three types of approach to nests (walking, running or leading a dog). We measured the flush distance, length of time parents spent off the nest and distraction display intensity. Leading a dog caused the greatest disruption of incubation, while responses to walking and running approaches did not differ significantly. Distraction display intensity appeared to be unrelated to approach type. There was evidence of habituation to humans on busy beaches. Our results provide the first experimental evidence that shorebirds perceive dogs as posing more of a threat than humans on foot, and that their subsequent avoidance response is greater. We recommend that human activity, particularly the walking of dogs, should be limited near nesting sites. Further study on causes of nest failure is required. (C) 2001 Elsevier Science Ltd. All rights reserved.