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Birds and bats of Rotuma, Fiji

Notornis, 66 (3), 139-149

A. Cibois; J.C. Thibault; D. Watling (2019)

Article Type: Paper

Rotuma, Fiji, is a small and isolated island in the Central Pacific, rarely visited by ornithologists. We present here our own observations on the avifauna, obtained in 1991 and in 2018, completed by previous records obtained since the 19th Century. The main changes on the species composition concern the extirpation of the white-throated pigeon and the settlement of the reef heron. The status of the four endemic landbirds (one species and three subspecies) is good, especially that of the Rotuma myzomela. However, the recent arrival of the common myna (2017–2018) represents a potential threat. We also observed that the Pacific sheath-tailed bat, which was abundant 30 years ago, has probably been extirpated from the island.



Parameters influencing selection of nest boxes by little penguins (Eudyptula minor)

Notornis, 66 (3), 129-138

H. Ratz (2019)

Article Type: Paper

Little penguins (Eudyptula minor) readily breed and moult in nest boxes. The selective placement of nest boxes can enhance their use, improve breeding success and increase recruitment. I examined nest parameters for 171 nest boxes at Pilots Beach, southern New Zealand, in relation to their use for breeding and for moulting in the 2016 breeding season. Linear models to assess the relative importance of nest box parameters produced definitive results where a higher likelihood of use was interpreted to indicate a preference. The only preference for breeding or moulting was for shaded boxes that were free of vegetation at ground level. These trends were supported by comparisons of proportions of boxes used for breeding and moulting that indicated shaded boxes surrounded by bare ground were preferred to unshaded boxes surrounded by introduced grasses. Proportions also indicated that boxes on flat ground with a flat entrance were preferred to boxes on sloped ground or a sloped entrance for breeding and moulting. About half of the boxes between 61 and 90 m distance to the landing were used for breeding and moulting. Females nesting in shaded boxes had a higher breeding success than those in unshaded boxes but their chick masses were similar. To optimise nest box use by little penguins and encourage recruitment, nest boxes ideally should be placed under bushes or artificial structures on open ground up to 90 m from the landing.


Breeding petrels of Chalky and Preservation Inlets, southern Fiordland – a test of the ‘refugia from resident stoats’ hypothesis

Notornis, 66 (2), 74-90

C.M. Miskelly; C.R. Bishop; G.A. Taylor; A.J.D. Tennyson (2019)

Article Type: Paper

Forty breeding colonies of three petrel species were found on 35 of 71 islands surveyed in southern Fiordland, Fiordland National Park, New Zealand, in November and December 2017. Almost all islands in Chalky Inlet, Preservation Inlet, Cunaris Sound, Long Sound, and Isthmus Sound were surveyed. Sooty shearwater (Ardenna grisea) was the most widespread and abundant species, with an estimated 23,425 burrows on 25 islands. Broad-billed prions (Pachyptila vittata) were breeding on nine islands (9,940 burrows estimated), and mottled petrels (Pterodroma inexpectata) on five islands (1,240 burrows estimated). This is a 3-fold increase in the number of petrel colonies in Chalky and Preservation Inlets and associated waterways identified in published accounts, and the first estimate of the number of burrows on each island. Long-term survival of most of these colonies is dependent on ongoing control of stoats (Mustela erminea) on islands in these southern fjords. The persistence of remnant petrel colonies on small islands is probably due to stoats being infrequent invaders that are unable to persist when migratory petrels depart at the end of the breeding season.

Effectiveness and efficiency of avian species detection: a comparison between field observers and automatic recording devices

Notornis, 66 (3), 109-128

J.A.J. Mortimer; T.C. Greene; P. van Dam-Bates; I.M. Westbrooke (2019)

Article Type: Paper

The monitoring of animal populations is essential for reporting on the state of the environment, with birds often used as indicators of ecosystem health. Traditionally, bird monitoring has been done by field observers; however,there has been recent interest in use of automatic recording devices (ARDs) as an alternative. A monitoring programme managed by the New Zealand Department of Conservation (DOC), used observers and ARDs concurrently for three survey seasons, providing the opportunity to compare results in terms of effectiveness and efficiency. The difference in species-richness estimates from the two methods was small, with the observer method detecting slightly higher numbers of species in all habitat types. Detection probabilities for individual species, derived from occupancy analysis, were similar between methods, with a few exceptions: bellbird (Anthornis melanura), brown creeper (Mohoua novaeseelandiae), tūī (Prosthemadera novaeseelandiae), North/South Island robin (Petroica longipes/australis), and rifleman (Acanthisitta chloris). Bellbird and rifleman had a higher probability of being detected by ARDs, whilst the remainder were more likely to be detected by observers. Differences in detection probability may be due to identification confusion in the case of bellbird and tūī, and observer ability to detect and identify birds visually for brown creeper and North/South Island robin. The relationship between indices of abundance from the observer and ARD methods varied between species and habitat types. These inconsistencies suggested that the ARD results did not correlate closely with observed abundance, which may limit the ARD method to provision of confirmed presence data. Observer counts proved to be more time efficient given present levels of processing technology, mainly due to the longer processing time required for ARD recordings. However higher numbers of people were required for observer counts, which may be problematic when there is a shortage of appropriately skilled observers at the required time of year.

The movements of juvenile and immature variable oystercatchers (Haematopus unicolor) from the Kaikōura Peninsula, South Island, New Zealand

Notornis, 66 (1), 23-30

L.K. Rowe (2019)

Article Type: Paper

Variable oystercatcher chicks (Haematopus unicolor) were banded at the Kaikōura Peninsula between summer 1999–2000 and summer 2016–2017. Prior to colour banding, there were no reports of Kaikōura Peninsula oystercatchers being sighted at other locations. Since summer 2006–2007 colour banding sequences have been available and these unique identifiers enabled movements of individual juvenile and immature birds to be determined. Forty-two colour banded chicks fledged, and 25 of these have been sighted at 11 locations between Collingwood 215 km to the northwest, and the Avon-Heathcote Estuary near Christchurch, 145 km south. Twelve of the 25 birds sighted away have not been seen back at the Kaikōura Peninsula, the other 13 returned of which 4 travelled away for a second time and did not return. Seventeen birds were not seen away from the Kaikōura Peninsula but 7 with no sightings for periods over 7 months may been away and returned. Siblings often went to different locations. Of 9 pairs of same nest siblings, 1 pair stayed at the Kaikōura Peninsula, 1 pair went initially to Nelson and 1 pair to the Avon-Heathcote Estuary, and birds of the other 6 pairs went to different locations including staying at Kaikōura. Birds seen at Nelson were also seen at the Avon-Heathcote Estuary.

Phenotypic variability within and between regional populations of Anas superciliosa (Anatidae)

Notornis, 66 (2), 64-73

M. Williams (2019)

Article Type: Full article

Variability of face and wing pattern and of leg and bill colour, and differences in bill and wing lengths, were assessed in Anas superciliosa (Anatidae) specimens from Pacific Islands, Australia, and New Zealand regional populations. The same 3 broad face patterns and 4 wing patterns were found in all populations. Frequency distributions of face patterns, but not wing patterns, differed significantly between populations. The most common face pattern in Australia was very rare in New Zealand and uncommon in Pacific Islands. A secondary face pattern in Pacific Islands and New Zealand was absent in Australia. Australian and New Zealand ducks did not share bill colour and pattern and no legs of New Zealand birds displayed yellow/orange hues common to 35% of Australian specimens. Bill and wing lengths of Pacific Islands specimens were significantly shorter than all others while wing lengths of male specimens from northern Australia were significantly shorter than those from southern Australia and New Zealand. These differences offer emphatic support for historic subspecific differentiation of Pacific Island specimens. Historic, but now discarded, taxonomic distinction between Australian and New Zealand populations based on phenotype could be reconsidered.



Major changes in the red-billed gull (Larus novaehollandiae scopulinus) population at Kaikoura Peninsula, New Zealand; causes and consequences: a review

Notornis, 65 (1), 14-26

J.A. Mills; J.W. Yarrall; J.M. Bradford-Grieve; M. Morrisey; D.A. Mills (2018)

Article Type: Paper

We use previously published and new data from a long-term study of the red-billed gull (Larus novaehollandiae scopulinus) population at the Kaikoura Peninsula to review causes and consequences of population change. Currently the largest colony in New Zealand, the Kaikoura population, has undergone major changes over the past 52 years. In 1994 the population began to decline, and between 1983 and 2003 it dropped by 51%. Fledging success varied markedly between seasons. The major cause of reproductive failure was predation by introduced mammals, especially ferrets (Mustela furo) and feral cats (Felis catus). These predators became a problem when rabbits (Oryctolagus cuniculus) and hares (Lepus europaeus) increased in number, enhancing the predators’ survival over-winter. Periodic failure in the availability of euphausiids, the main food of red-billed gulls, swamping of nests during high seas, and chilling of nestlings during long periods of bad weather also have been set backs to the population. However, in the absence of predation, these factors produced only a temporary impact to the population of long-lived gulls. The decline in both body size and survivorship of adults over the last 5 decades indicates that there are other factors at work, and indicate that the population has experienced some form of unfavorable environmental condition or stress over a long period.


From wetlands to islands: morphological variation, plumage and song in Pacific island Acrocephalus warblers

Notornis, 65 (4), 202-222

B.D. Bell (2018)

Article Type: Paper

Acrocephalus warblers occur across Eurasia, Africa, and Australasia, where they are typically migratory, wetland species, but also occur on islands as sedentary endemics in drier habitats, including forest and scrub. External morphology and song amongst Pacific island Acrocephalus warblers were investigated and comparisons made with Acrocephalus species elsewhere. There was a range of sizes between Pacific island Acrocephalus warblers, many being larger than migratory continental species. Bill:wing length ratios were higher in most Pacific species, and their wings more rounded, than most continental species, but less rounded than swamp-warblers of Africa and adjacent islands. Plumages of W and N Pacific species resembled reed-warblers elsewhere, but in SE Polynesia were more varied, brown or grey dorsally, shaded olive, yellow or rufous, and pale ventrally, shaded white, yellow or buff-white, with a melanistic morph on Tahiti. Spectrographic analysis showed a gradient of song complexity from continental and Marianas/Micronesia species (A. hiwae, A. syrinx), through to A. taiti and A. vaughani on the Pitcairn islands, which had no song. The mean frequency of Pacific island reed-warbler songs was inversely correlated with mean body size.

The status of the red-billed gull (Larus novaehollandiae scopulinus) in New Zealand, 2014–2016

Notornis, 65 (1), 1-13

P.G.H. Frost; G.A. Taylor (2018)

Article Type: Paper

A national survey of breeding red-billed gulls (Larus novaehollandiae scopulinus) was carried out during 2014–2016 to establish the present status of the species. Observers were asked to find and report all breeding colonies, starting with a check of previously reported breeding sites. Standardised means of conducting these surveys were developed, publicised, and largely applied. Around 27,831 pairs of red-billed gulls were recorded nesting in New Zealand during the survey: 14,713 pairs at 122 South Island sites; 12,676 pairs at 124 North Island sites; and 442 pairs at 14 sites on the Chatham Islands. Other than colonies on the Three Kings Islands (1,763 pairs) and Takapourewa/Stephens Island (1,250 pairs) there were no large concentrations on offshore islands. The largest mainland concentrations were at Kaikoura (3,210 pairs), Taiaroa Head (2,145), Rotorua (2,277) and Marsden Point (1,190). Although the accuracy of previous estimates is questionable, the red-billed gull nevertheless appears to have declined nationally since the mid-1960s. Possible reasons for the decline are discussed and a proposal for future monitoring of the species is proposed.


An estimate of the Hutton’s shearwater (Puffinus huttoni) population in the Kaikōura region using colour-marking in 2002 and 2014

Notornis, 65 (4), 196-201

L.K. Rowe; P.R. Scofield; G.A. Taylor; R.J. Barker (2018)

Article Type: Paper

In September 2002 and 2014 respectively, 2,077 and 1,704 prospecting Hutton’s shearwaters were colourmarked on the ventral plumage at their breeding grounds at Kōwhai River, Seaward Kaikōura Ranges, New Zealand. Large numbers (425,516 in 2002, and 106,900 in 2014) of marked and unmarked birds were then counted from small boats off the Kaikōura coast between Haumuri Bluff and Ohau Point. A hypergeometric sampling model was fitted these counts, leading to population estimates of N =̂ 459,290 (95% CI = 434,306-484,733) birds in 2002 and N ̂ = 590,407 (95% CI = 543,992–642,697) individuals in 2014. These estimates include both breeding and non-breeding birds and indicate that between 2002 and 2014 the population trend was about +2% per year.