Gary & Robyn Wilson | Guest Contributors
To those more familiar with birds in Australia, the relative lack of them and the apparently vacant niches in New Zealand come as a surprise. Not only have we, in New Zealand, lost about 56 species – 37 of them between the arrival of the Polynesians and the Europeans, and 19 subsequently (Roberson and Heather 2015) – but a number of others are on the verge of extinction.
One of the questions for us is, why haven’t more Australian species become established in New Zealand, particularly given those apparent empty niches?
The answer in part is that some have: other species are becoming established in New Zealand more slowly, thus are in lesser numbers than might be expected.
In mid-2024 we were involved in surveying the numbers of the Royal Spoonbill Platalea regia in New Zealand, one of those species that has established here in recent times.
The results of that mid-2024 count in which we were involved, are shown in Figure 1 below.
Royal Spoonbills were first noted breeding amongst White Heron (sic), (Great White Egret) Ardea alba modesta at Okarito (about 42℃ S) on the South Island in 1949, and they continue to do so. Numbers remained low until 1990 when they started to increase markedly. Each summer the birds breed here, and then most disperse mainly to the north of the North Island for winter. Twelve National Surveys have been conducted: the first in 1977, with 500 sites surveyed in 2024.
The number of Royal Spoonbills in New Zealand has nearly doubled in the past 12 years with 4,593 birds counted: 86% of them in the north of the North Island. In the South Island, 5% of birds that breed there were counted in the Nelson area, on the northern end of the South Island, but in 2024 they constituted only about 5% of birds counted, down around 50% significantly since the last census.
The annual rate of growth in numbers of Royal Spoonbill over the past 12 years was about 7.8%, down from 12% in the previous decade, suggesting the rate of population growth may have slowed. It is likely the population growth has been the result of successful breeding in New Zealand, but further influxes of birds from Australia cannot be ruled out.
What then of the Yellow-billed Spoonbill Platalea flavipes in New Zealand? After all they are widespread in Australia and the range of the two species overlaps, although the Yellow-billed has a preference for inland wetland habitats.
There are only two records of Yellow-billed Spoonbill in New Zealand, with the same records in Robertson and Heather (2015) and eBird (accessed 05/02/2025), neither recent (1976 and 1981 respectively), both on swamps or flooded pastures, and the former with an Australian White Ibis and two Royal Spoonbill. It seems the Yellow-billed Spoonbill is an infrequent visitor to our shores and given the >90% loss of wetlands in this country unlikely to establish here.
Reference
Robertson H & Heather B (2015). The Hand Guide to the Birds of New Zealand. Penguin, Random House, New Zealand.