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Detecting population trends of Gibson’s and Antipodean wandering albatrosses

Notornis, 52 (4), 215-222

G. Elliott; K. Walker (2005)

Article Type: Paper

Counts, mark-recapture estimates of abundance, and simulations were used to assess the population trends of Antipodean wandering albatross (Diomedea antipodensis) and Gibson’s wandering albatross (D. gibsoni). Estimates of population size based on mark-recapture analysis had much greater power to detect trends than did annual counts of nests. In fact, nest counts were so variable that significant trends would only be detected when populations had already changed by more than 25%. Population simulation models were constructed using survival and productivity data from the two species, and recruitment data from closely related species. The simulation models were sensitive to variation in recruitment data and suggested that the recruitment of Gibson’s wandering albatrosses is significantly lower than that of Antipodean wandering albatrosses. The sensitivity of the models to variation in the surrogate data compromises the usefulness of such models as predictive tools. After large, probably fisheries-induced declines during the 1970s and 1980s, Antipodean wandering albatross populations are now increasing at about 3.1% per annum, while Gibson’s wandering albatross populations are static.

Failed attempts to reintroduce bellbirds (Anthornis melanura) to Waiheke Island, Hauraki Gulf, 1988-91

Notornis, 52 (3), 150-157

M. Lee (2005)

Article Type: Paper

New Zealand bellbirds (Anthornis melanura) disappeared suddenly from the northern New Zealand mainland and several large northern islands in the late 19th century. During the past 75 years, several unsuccessful attempts were made to reintroduce them. Between 1988 and 1991, four translocations (111 birds) were made to Waiheke Island near Auckland, sourced from Kaingaroa (21 birds) and Cuvier Island (90 birds). The birds were conspicuous immediately after release but became progressively less visible within six months and the translocations failed. While the cause(s) of failure are unknown, predation by mammalian predators, especially ship rats (Rattus rattus) is likely to have been a critical factor. Other possible reasons for failure of bellbird translocations are discussed, along with the reasons why original bellbird populations disappeared from northern New Zealand and subsequently failed to re-establish.

The occurrence of owls in the Marshall Islands

Notornis, 51 (3), 147-151

D.H.R. Spennemann (2004)

Article Type: Paper

Short-eared owls (Asio flammeus) are capable of crossing long stretches of open water and have been successful colonisers of islands. In the central and western Pacific two established populations (on Hawai’i and on Pohnpei in Micronesia) seem to be the foci of repeated dispersal events. The paper reviews the historic and linguistic record for the occurrence of short-eared owls on the scattered atolls of the Marshall Islands, the easternmost group of Micronesia.

Abundance and breeding distribution of the white-flippered penguin (Eudyptula minor albosignata) on Banks Peninsula, New Zealand

Notornis, 51 (1), 1-6

C.N. Challies; R.R. Burleigh (2004)

Article Type: Paper

A survey of the white-flippered penguin (Eudyptula minor albosignata) nesting colonies on Banks Peninsula, New Zealand was made during the 2000/01 and 2001/02 breeding seasons. Sixty-eight colonies were found of which 51 contained 5-20 nests, 12 21-50 nests, and 5 >50 nests. Altogether there were 2112 nests which equates to a population of c. 5870 birds. Adding the estimated 1650 nests on Motunau Island gave a total population for the subspecies of c. 10,460 birds. The colonies were distributed right around the peninsula with their occurrence increasing from west to east. Most were situated either on the peripheral coast (47%) or inside bays within 1 km of their entrance (38%). All but three of the colonies were on debris slopes below coastal bluffs with the nests concentrated mainly in rock piles. One colony was on an islet, and the other two were on farmland around the heads of bays. Thirty-four of the colonies were considered accessible to introduced mammalian predators, and 14 contained evidence predators had been present. If predator numbers remain high it seems inevitable that many of the surviving penguin colonies will be lost and others reduced in size.
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