Discriminant function analysis (DFA) was used to determine gender and geographic variation in the morphometrics of white-chinned petrels (Procellaria aequinoctialis) measured from fisheries bycatch in New Zealand. Samples were divided into 5 clusters based on capture location. A DFA model was created using adult breeding birds presumed to be from the 2 main locations at the Auckland Islands and Antipodes Islands. Geographic variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, right and left mid-toe and claw, tail, and right and left wing was found between birds presumed to be from the ‘Auckland’ and ‘Antipodes’ clusters, with ‘Antipodes’ birds being generally larger than ‘Auckland’ birds. Gender variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, minimum bill depth, right and left mid-toe and claw, right wing, right and left tarsus existed for ‘Auckland’ birds. Gender variation in head and bill, skull width, culmen, culmen depth at base, culmen width at base, minimum bill depth, right and left mid-toe and claw, and tail existed for ‘Antipodes’ birds. Birds in the other 3 clusters were classified as originating from the Auckland Islands or Antipodes Islands. The clustering suggested that birds from the Auckland Islands tended to forage mostly north and west, whereas birds from the Antipodes Islands foraged mostly towards the north. There were large overlaps at Puysegur Point and particularly the Chatham Rise of birds from both breeding locations. This study shows the usefulness of bycatch necropsies, and emphasises the need for further studies in geographic variation and sexual dimorphism at all New Zealand breeding locations.
The Chatham Island duck (Anseriformes: Anatidae: Anas chathamica) had a pronounced and rugose enlargement to the tip of the processus extensorius at the proximal end of its carpometacarpus. This “carpal knob” was the equal in size of those found in some much larger waterfowl (e.g., steamer ducks, Tachyeres sp.), and was disproportionately larger than those of all other New Zealand waterfowl. The knobs on 20 carpometacarpi examined all showed evidence of continuous bone deposition at their tips and their use as weapons is implied. Comparisons with other duck species having similarly prominent and rugose carpal knobs suggests the Chatham Island duck maintained long-term pair bonds and occupied combined feeding and breeding territories year-round which both sexes defended belligerently.
Banded rails (Gallirallus philippensis) were surveyed in saltmarshes and mangrove fringed habitats at Onerahi, Whangarei, New Zealand. A total of 13 sites were surveyed 3 times per year around sunset during late spring in 2004, 2007 and 2013. On average 4.41 calls were heard per hour. Banded rails were detected at 12 sites with between 0.01 and over 2 ha of saltmarsh and extensive mangroves, but not a saltmarsh site lacking mangroves. Occupancy models favoured those with no change in occupancy state, seasonal detection, and there was with some support for random colonisation of sites. Records from Awaroa Creek indicate that rails can be detected from late afternoon calls throughout the year. Surveys should include the half hour before until at least 10 minutes after sunset.
Discriminant function analysis (DFA) is widely used to determine sex in the field from morphological measurements of bird species with monomorphic plumage. Sexual dimorphism was examined in black petrels (Procellaria parkinsoni) using 7 external measurements of adult birds breeding on Great Barrier Island, New Zealand. Males were significantly larger than females in absolute values of all measurements except for tarsus. Two stepwise DFA models were developed. The first used all 7 parameters, while the second model used only 6 parameters in order to increase sample size. Model one and two showed an 88 and 82% classification success, respectively, most likely due to the high overlap in measurements between males and females. These canonical functions were not accurate enough for field surveys, but may be improved using a larger and more representative sample size.
The monitoring of endemic birds during the control of introduced mammalian predators is a common practice at community-based conservation projects in New Zealand. We describe long-term trends of endemic passerines monitored using the presence-absence technique during the control of stoats (Mustela erminea) and brushtail possums (Trichosurus vulpecula) in the Flora Valley, near Nelson, New Zealand. Data collected over an 8 year period by Friends of Flora, a community-based organisation, suggests that bellbirds (Anthornis melanura) significantly increased, while South Island robin (Petroica australis), tomtit (P. macrocephala) and rifleman (Acanthisitta chloris) populations showed little or no change, and grey warblers (Gerygone igata) significantly decreased. All species showed a greater increase during the first 4 years of the survey compared to the second 4 years, which suggests that meso-predator release of rats may have occurred from ~4 years after the start of the surveys. The presence-absence technique is simpler to conduct than the more commonly used 5-minute bird count method, and thus may be better suited for use by the community sector in similar situations.
We present counts of white blood cells of wild and clinically normal red-crowned parakeets (Cyanoramphus novaezelandiae) from 2 island populations in New Zealand. Total white blood cell counts on slides prepared in the field and counts of relative proportion of basophils, eosinophils, heterophils, lymphocytes and monocytes were determined for 33 individuals caught on Little Barrier Island and 48 individuals caught on Raoul Island. Mean haematological parameters were: total white blood cells 6.85 cells x 109/L, lymphocytes 5.0 x109/L (74.0%), monocytes 3.5 x109/L (5.7%), eosinophils 4.6 x109/L (6.4%), basophils 1.9 x 109/L (3.1%), and heterophils 9.9 x109/L (14.7%). Raoul Island parakeets had significantly higher counts of white blood cells, lymphocytes, and heterophils than Little Barrier Island parakeets, possibly reflecting latitudinal differences. Males showed significantly higher counts of white blood cells and lymphocytes than females. White blood cell counts on slides prepared in the field represent an inexpensive and straightforward technique to determine variation in the levels of each cell type and to assess the physiological state of healthy and diseased individuals. This information is useful for veterinary clinicians, wildlife managers, and conservation biologists who increasingly require methods for health assessment, disease diagnosis, and screening for pathogenic microorganisms on species of conservation concern.
Twenty five bird species were recorded following 2 brief winter visits to the southern Kermadec Islands during 2002 and 2006. Of these, 15 were seabirds and 10 land or shorebirds. Rapid changes in the dominant vegetation cover occurred between 1988 and 2002. Ferns replaced grass and sedge swards over much of the island, and although this succession was rapid, the distribution of woody species (the presumed historical dominant cover) did not change, most likely due to limited seed sources, Pacific rat (Rattus exulans) predation, and competition for space from other species. Possible impacts of these changes on the avifaunal composition of Macauley Island are discussed. Following the presumed eradication of Pacific rats from Macauley Island in 2006, recommendations are made for future vegetation and bird monitoring.
Opportunities to monitor natural island ecosystem recovery following the eradication of introduced predators are rare, and provide a useful comparison for recovery programmes aided by active habitat restoration and species translocations. We present an assessment of the current avifauna on Burgess Island, Mokohinau Group, 2 decades after kiore (Pacific rat; Rattus exulans) removal. The 4 most abundant land bird species we recorded are red-crowned parakeet (Cyanorhamphus novaezelandiae), bellbird (Anthornis melanura), tui (Prosthemadera novaeseelandiae) and silvereye (Zosterops lateralis), all New Zealand native taxa. Our records confirm that 46 species now utilize the island’s habitats, compared with 24 species reported from the literature during the last decades of rat infestation. We also confirm breeding of 9 seabird species by 2011, only 4 of which maintained breeding populations on Burgess Island prior to rat eradication. More than 20 years after predator removal, Burgess Island hosts a rich avifauna, and provides a valuable example of natural recovery following predator eradication without any further active restoration measures.
Numbers of bellbird (Anthornis melanura), an endemic honeyeater, counted along transects in forest remnants on the Port Hills near the city of Christchurch, New Zealand, increased since the initiation of intensive mammalian pest control in 2006. Bellbird counts also increased along transects in bush reserves and along a 6.5 km cycle route in the city itself, probably as a result of spill-over from source populations on the Port Hills, because few bellbirds breed in the city. In contrast, counts of bellbirds in domestic gardens in the city did not increase, perhaps because of the continued presence of introduced mammalian predators and/or lack of suitable habitat. We suggest the increased abundance of bellbirds in forest remnants on the Port Hills was likely the result of mammalian pest control but the lack of ‘no-treatment’ areas means we cannot rule out other causes of the increase such as changing habitat and food availability.
Calls and playback-response behaviour of breeding wedge-tailed shearwaters (Puffinus pacificus) were studied at Muttonbird Island, Coffs Harbour, New South Wales, Australia. Burrow calls were recorded from 45 females and 60 males. Male calls averaged higher in fundamental frequency and longer in note lengths than female calls, although ranges overlapped. Playback experiments demonstrated sexual recognition, with incubating females mostly responding to female playbacks. Males responded to both female and male calls. Ratios of between- to within-subject variation suggested that individual vocal signatures could be encoded in timing and some frequency parameters. Playback experiments demonstrated a “dear enemy” effect, where shearwaters in burrows were more responsive to stranger rather than neighbour calls. Wedge-tailed shearwater calls are informative and further studies are encouraged for other southern hemisphere breeding shearwaters.
Royal spoonbill (Platalea regia) nestlings (n = 158) were colour-banded between 1990 and 2005 at Green Island, Otago and Wairau lagoons, Marlborough. A total of 75% and 84% of Otago and Wairau birds, respectively, were resighted between 1991 and 2012. The pattern of independent resightings (n = 737) indicates that adult royal spoonbills in New Zealand undertake repeated seasonal inter-island migration, moving north to wintering sites (mainly Parengarenga, Rangaunu and Whangarei, up to 1200 km away), then relocating to the south again in summer to breeding sites. Most juveniles move as far north as adults, although a third of juveniles from Wairau were seen in winter in the Nelson region, a distance of < 100 km away. Juveniles and immatures (< 2 year old) remain in northern locations in summer, and return as adults (2 years and older) to their natal area. In summer all adult birds banded in Otago were resighted only in Otago, which indicates a high degree of philopatry. In contrast, a third of nestlings banded at Wairau were resighted as adults in the Otago area, indicating a southward natal dispersal. The annual survival rate is estimated to be 0.89 and 0.92 for Otago and Wairau birds, respectively. The oldest bird seen alive was 18 years and 3 months.
It is difficult to locate and monitor populations of the New Zealand falcon (Falco novaeseelandiae) because the terrain they occupy is frequently inhospitable and the traditional method of walking transects lines to locate nest sites is arduous and time consuming. For this reason we developed and trialled a low-priced broadcasting system that amplifies pre-recorded vocalisations to attract falcons, which we then used to locate their nest sites. We tested the system on 20 falcons in the Kaingaroa and Pan Pac forests on the North Island. Both sexes responded but males responded more frequently. We conclude that the system can rapidly and accurately locate falcons in a large plantation forest during the summer breeding season.