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.
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.
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.
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.
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.