We estimated apparent annual survival of adult and young grey-faced petrels (Pterodroma macroptera gouldi) and age of first return to the natal colony of young birds from 2 colonies in the Bay of Plenty, New Zealand, between 1991 and 2008. We analysed the capture histories of 5844 adult birds and 928 chicks in a mark-recapture framework. The apparent adult annual survival rate was 0.89 after accounting for transience effects, which were greater at the mainland site (Mauao, Mount Maunganui) than on the island colony (Motuotau, Rabbit Island). Annual survival of young birds between fledging and 2 years of age was 0.844 for Mauao and 0.865 for Motuotau. Around 50% of fledglings that returned to their natal colony did so by 4 years of age, and by age 6, the probability of a fledgling returning was approximately 1.0. These are the first reliable estimates of these parameters for grey-faced petrels and are vital for models aimed at predicting the effects of natural perturbations or management interventions on breeding populations.
We report Records Appraisal Committee (RAC) decisions regarding Unusual Bird Reports received between 1 Aug 2008 and 31 Dec 2010. Among the 58 submissions accepted by the RAC are the 1st New Zealand records of streaked shearwater (Calonectris leucomelas) and straw-necked ibis (Threskiornis spinicollis), 2nd records of great shearwater (Puffinus gravis), semipalmated plover (Charadrius semipalmatus) and Franklin’s gull (Larus pipixcan), and 3rd records of little stint (Calidris minuta) and black kite (Milvus migrans). Other notable records included the 1st oriental cuckoo (Cuculus optatus) from the Kermadec Islands, a New Zealand dabchick (Poliocephalus rufopectus) near Nelson, and 2 records of Stewart Island shag (Leucocarbo chalconotus) near Lake Ellesmere, Canterbury.
We investigated the population size and annual survival of Salvin’s albatrosses (Thalassarche salvini) breeding at the Western Chain, The Snares, New Zealand. A count of breeding pairs during incubation resulted in totals of 1100-1200 breeding annually on Toru and Rima Islets in the 3 years 2008-2010; none was seen breeding on Tahi, Rua or Wha Islets. The majority of adults bred annually. Based on banding and recapture the annual survival probability of breeding birds was estimated to be 0.967 while that of known-age birds banded as chicks in Feb 1986 was estimated at 0.939. A bird banded as a chick on the Bounty Is in 1985 was found breeding on Toru Islet of the Western Chain in the 3 years 2008-2010. This is the first record of a banded Salvin’s albatross breeding away from its natal island.
Home range size, travel distances, and population density of the great spotted kiwi (Apteryx haastii) were investigated in the North Branch of the Hurunui River. Radio tracking was conducted on 10 great spotted kiwi between Dec 2007 and Apr 2008. The estimated minimum home-range sizes were determined using the concave polygon method and ranged between 19.6 ha and 35.4 ha, with a mean of 29.3 ha (± 1.6 SEM). The observed nightly distances travelled per hour varied from 7 to 433 m (n = 569). Most estimates of travel distances (73%) were clustered in the classes from 0 – 150 m/hour, and distances over 200 m/hour were seldom achieved (only c. 7% of distances). The kiwi population in the Mainland Island site on the western North Branch of the Hurunui River was estimated to hold around 290 birds in total. Population density for the entire North Branch area was estimated to be 2 pairs/km² and when including subadults, 5 birds/km². Our estimate of home range size is larger but with more variation than found in other studies. Differences in population density estimates between our study and those in the Hurunui and Arthurs Pass district may be due to different objectives and methods.
Population size and breeding success of northern New Zealand dotterels (Charadrius obscurus aquilonius) were studied on the recently mammalian predator-eradicated Motuihe Island in the Hauraki Gulf, New Zealand. The island’s entire breeding population was monitored during the austral breeding season from Nov 2007 – Feb 2008. Nine breeding pairs were identified and their breeding success recorded. A total of 41% of nesting attempts produced fledglings and 1.22 chicks fledged per pair for the season; each egg had a 38% chance of survival to fledging. The breeding success of this endemic shorebird was twice as high on Motuihe Island as that at unmanaged mainland sites, and is comparable to levels of breeding success at other managed sites with mammal trapping or predator-proof fencing. The only identified cause of nesting failure over the breeding season was avian predation. Suggestions are made to maintain and enhance breeding success at this locality.