Between the 1850s and the early 1900s, most of the native forest of western Taranaki was systematically destroyed. This destruction likely accounted for the disappearance of bellbirds (Anthornis m. melanura), and other native birds, from most of that area. The return of bellbirds to New Plymouth in the 1920s may have been a direct result of increased food that had become available to them there. However, bellbirds have recently become rare visitors to New Plymouth. This may be the result of a possible reduction in the population of bellbirds in nearby Egmont National Park and/or increasing ambient temperatures in cooler months of the year.
A small black-and-white storm petrel seen off Whitianga, New Zealand, in Jan 2003 was tentatively identified as a New Zealand storm petrel (Pealeornis maoriana). A further sighting in the Hauraki Gulf in Nov 2003 of multiple birds identified as New Zealand storm petrels led to the realisation that the species was both extant and apparently locally common. Prior to these sightings this enigmatic seabird was known only from 3 specimens collected in the 1800s, and unreported since. This paper reviews these 2 sightings that constitute the rediscovery of an ‘extinct’ species not reported for more than 150 years. Possible reasons for the lack of sightings before 2003 are discussed and a review of black-and-white storm petrel records prior to 2003 around northern New Zealand is presented.
The nesting of variable oystercatchers (Haematopus unicolor) on the Kaikoura Peninsula was studied at 6 sites over 8 years. Only in 1 year were birds known to have laid eggs at all 6 sites and only at 2 sites was nesting observed every year. Loss of nests often resulted in re-nesting and at 1 site birds made 4 attempts in 1 season. Over the 8 years, 117 eggs were found in 53 nesting attempts between mid-Oct and late Jan. The average size of 114 eggs was 58.2 x 40.6 mm. Thirty of 53 nesting attempts were completed and averaged 2.4 eggs/clutch (range 1–3 eggs). Twenty three chicks hatched from observed nests: this comprised 20% of eggs laid, 32% of eggs from completed clutches, and 72% of eggs from successful nests. At least 7 more chicks hatched from nests not found. A total of 17 chicks fledged including 6 chicks from nests not found. The other 11 fledglings came from 13 nests with hatchlings (0.84 chicks/nest; 41% of the eggs laid), 30 completed nests (0.37 chicks/nest; 15% of the eggs from these nests) and 9.4% of all eggs laid. Including chicks from 3 nests not found increases fledging to 1.06 chicks/nest with hatchlings, 0.51 chicks/completed nest and about 14% of eggs laid. Newly fledged young were seen from 26 Dec until mid-Mar. High tides washed away several nests, seals squashed eggs in 1 nest, and 1 adult was probably killed by a cat. While people walk in the vicinity of nesting, there was no evidence that they caused egg or chick losses.
Singing and territorial behaviour of North Island tomtits (Petroica macrocephala toitoi) were used to monitor population size over a 3-year period at Atuanui, Mount Auckland Scenic Reserve, North Auckland. Male tomtits were observed singing year-round with singing peaking in the period from Nov to Jan. The general territorial behaviour of Atuanui tomtits was similar to that reported for other North Island populations, with territorial males resident in all months and most territories occupied in successive years. Density of territories was stable over the 3-year period but vacancies in suitable habitat suggest the population is not at carrying capacity.
During 1971-75 and 1991-95, surveys of Caspian tern (Sterna caspia) colonies throughout New Zealand were carried out. The breeding population in 1971-75 was 1266 pairs, in 16 colonies, predominately in the northern North Is. In 1991-95, there were 1190 breeding pairs found in 17 mainly northern colonies, suggesting the population had been relatively stable over the 20-year period. As census methodology may under-record the breeding of isolated pairs, we included an estimate of the number of isolated pairs to give a total national population of 1300-1400 breeding pairs. This is less than 3% of the global population. Colony size and location showed some change between survey periods; 6 colonies disappeared and 8 new colonies were formed. Addition surveys in 2011-2015 are recommended to compare recent population trends.
I conducted road counts on the North I and South I of New Zealand in Mar 2006 to evaluate relative abundance and distribution of Australasian harriers (Circus approximans). Over 1670 km were traveled on the North I with 98 harriers detected, yielding 1 harrier/17.0 km traveled. Over 2430 km were traveled on the South I with 145 harriers detected, yielding 1 harrier/16.8 km traveled, with no difference in number of harriers detected/km traveled between islands (P > 0.25). Three survey routes, 1 on southeastern North I and 2 on northeastern and east-central South I, were particularly productive yielding 1 harrier/7.1-11.1 km traveled. My results provide empirical support for the frequently cited description that the Australasian harrier is now New Zealand’s most abundant native diurnal raptor, and has largely benefited from the conversion of land from native forest and scrub to pasture at the likely expense of other native and endemic species.
The effects of a range of habitat variables on spatial variation of breeding burrow density of sooty shearwaters, Puffinus griseus, were measured on 5 islands near Rakiura (Stewart Is) and 1 island in The Snares Is group, during the 2000-01 breeding season. Density estimates for 4 islands where Rakiura Maori harvest chicks ranged from 0.30 to 0.47 burrows per m2. Density on 2 non-harvested islands occurred at opposite ends of the burrow density spectrum (Whenua Hou, 0.09 entrances per m2; The Snares, 0.90 per m2). Burrow density was consistently lower in areas with shallow soil, in inland areas, and where there was more plant debris on the forest floor. The latter may reflect cause or effect because the birds drag woody and leafy debris into their burrows to form nests and to block the burrow entrance. Large amounts of variation in burrow density were not explained by habitat predictors. Detection of harvest impacts on sooty shearwater density on harvested and non-harvested islands will be more powerful if models account for soil depth and island edge-effects, but disregard vegetation variation.
In Jul and Aug 2005, 18 North Is kokako (Callaeas cinerea wilsoni) were released into a 450-ha area of New Zealand native forest subject to intensive control of introduced mammalian predators. The area, Ngapukeriki (near Omaio, Bay of Plenty, New Zealand), lies within a 13,000-ha matrix of native and exotic forest subject to lower and variable degrees of predator control. In contrast to most previous kokako translocations, this project employed 3 tactics to maximise the likelihood that kokako would remain in the target area: 1) many birds were released in a short period; 2) playback of kokako song was broadcast in the release area (potentially creating an “acoustic anchor”); and 3) a kokako pair was held at the release site in an aviary. Most birds approached to within 20 m of playback speakers, some approaching repeatedly. Several interactions between released birds were observed, including vocal interactions and instances of birds associating with one another temporarily. Visits to the aviary pair were rare. On 13 Apr 2006, all 8 trackable birds and 4 birds whose transmitters had failed remained in the core management area; locations of remaining birds (with lost or non-functional transmitters) were unknown. At least 5 territorial pairs had formed, and 1 chick was known to have fledged. To our knowledge, this was the 1st time song playback had been used as an attractant in a terrestrial bird reintroduction.
Natal dispersal of the New Zealand falcon (Falco novaeseelandiae) was documented using relocations of radio-tagged and colour banded falcons in Kaingaroa pine plantation. The age at which fledglings commenced natal dispersal was highly variable. The earliest fledglings dispersed 42 days after fledging, whilst others did not disperse out of their natal territories, remaining there to breed. After 91 days, 87% of fledglings had begun dispersal out of their natal territory. The mean time for the onset of dispersal was 76 days. Males generally dispersed earlier than females, but no significant difference was recorded. Both radio telemetry and colour band recoveries indicated that a large proportion of fledglings dispersed out of the study area. Mean natal dispersal distance within Kaingaroa Forest was 9.6 km. No significant difference was observed in natal dispersal distances between the sexes, although males generally roamed further afield than females. During this study, several females were recorded successfully breeding during their 1st year, a year earlier than usual. Males did not attempt to breed until they were 2 years old. We conclude that the high emigration rates and favourable breeding conditions in pine plantations make these habitats highly likely to act as source populations for neighbouring areas where populations of the New Zealand falcon may be in decline.