Impact of management on the breeding success of the northern New Zealand dotterel ( Charadrius obscurus aquilonius ) on Matakana Island, Bay of Plenty | Notornis and Birds New Zealand

摘要

The breeding success of northern New Zealand dotterels (Charadrius obscurus aquilonius) on Matakana Island, Bay of Plenty, was determined over 8 seasons (1992/93-1999/2000) in managed and unmanaged areas. Management to enhance breeding success included shifting nests to reduce the risk of flooding during spring tides and storms, and reducing predator populations of brushtail possum (Trichosurus vulpecula), feral house cat (Felis catus), Norway rat (Rattus norvegicus), stoat (Mustela ermines), and southern black-backed gull (Larus dominicanus) at dotterel breeding areas. Measures taken to reduce the incidence of disturbance by people on breeding dotterels included erecting fences around nesting areas, and speaking to members of the public about the plight of the species. The number of breeding pairs on Matakana Island fluctuated between 19 and 31 during the 8 seasons. Overall, 35.1% of 276 nesting attempts resulted in broods hatching. The main causes of nest failure during incubation were flooding by high tides or storms, and predation. The proportion of nests in which 1 or more eggs hatched was fairly stable during the 1993/94 to 1997/98 seasons at 26.1-33.3%, but was 68.0 and 51.3% in the last 2 years. This marked improvement in nesting success was attributed to the increased duration of pest control: starting before dotterel breeding began and continuing until most broods had fledged. Nesting success during incubation in managed habitat (47.5%) was significantly greater than in managed habitat (19.5%). Overall, 52.6% of chicks fledged. The number of chicks fledged per season (5 - 33), and fledglings produced per breeding pair (0.26 - 1.08) increased through the study In conclusion, we make suggestions to further promote the conservation of the northern New Zealand dotterel.