Predation at Sooty Shearwater Puffinus griseus colonies on the New Zealand mainland: is there safety in numbers?

1999 ◽  
Vol 5 (4) ◽  
pp. 347 ◽  
Keyword(s):  
New Zealand ◽  
Conceptual Model ◽  
Breeding Success ◽  
Rattus Norvegicus ◽  
Breeding Birds ◽  
Breeding Failure ◽  
Safety In Numbers ◽  
Breeding Seasons ◽  
Norway Rats ◽  
Extinction Vortex

Burrow occupancy, survivorship, and breeding success were assessed at eight Sooty Shearwater Puffinus griseus colonies along the southeastern coast of New Zealand during the 1994/95 and 1995/96 breeding seasons. An average 46% and 47% of burrows contained breeding birds, but only three colonies had chicks survive to fledge. Most breeding failures were at the egg and early-chick phase. A large proportion of adults were killed at some places, causing the extinction of two of our study colonies. Predation by Stoats Mustefa erminea was the main cause of breeding failure and adult loss at most mainland colonies, but Norway Rats Rattus norvegicus were the principal predator at one colony. Protection of adults, eggs and young chicks from predators is crucial if mainland colonies are to persist. A conceptual model predicts that predation becomes part of the extinction vortex as the size of a colony dwindles because the depredations of a few rogue predators have catastrophic impacts on the few remaining birds.

Effects of habitat and introduced mammalian predators on the breeding success of Yellow-eyed Penguins Megadyptes antipodes, South Island, New Zealand

1999 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Hiltrun Ratz ◽  
Brian Murphy
Keyword(s):  
New Zealand ◽  
Breeding Success ◽  
East Coast ◽  
Marked Effect ◽  
Forest Edge ◽  
Introduced Predators ◽  
Mammalian Predators ◽  
Predator Abundance ◽  
Breeding Seasons ◽  
Predator Guild

The endemic Yellow-eyed Penguin Megadyptes antipodes is threatened by habitat loss and introduced predators on mainland New Zealand. Nine colonies in the Catlins (south-east coast of South Island) were studied to measure breeding success, penguin abundance, and predator abundance in three successive breeding seasons (1991/92 to 1993/94). Nest numbers increased in all nine colonies in the three years despite predation (probably by Stoats Mustefa erminea) being the most important cause of breeding failure. Larger colonies with higher breeding success were in small gullies with limited shrubs and bushes rather than in the most intact mature forest colonies hitherto assumed to be optimal habitat for the birds. Penguin nests were concentrated near the forest edge, but predators were not, so the predation risk was not elevated near the forest edge. Fragmentation of the original forest habitat had no observable adverse effect on breeding success. Stoats dominated the predator guild, while Ferrets M. furo and Feral Cats Felis catus were rare. Trapping to kill predators early in the season had no marked effect on subsequent predation losses, but trapping intervention when a predation outbreak occurred curtailed further chick deaths. A simple population model predicts that Yellow-eyed Penguins populations will grow provided the average total chicks loss is less than 43% per season, or at least 0.85 chick per nest fledges each year. This requires predation losses to be less than 34%.

Population ecology of Norway rats (Rattus norvegicus) and interference competition with Pacific rats (R. exulans) on Raoul Island, New Zealand

2006 ◽  
Vol 33 (7) ◽  
pp. 539 ◽  
Author(s):  
Grant Harper ◽  
Dick Veitch
Keyword(s):  
New Zealand ◽  
Population Ecology ◽  
Rattus Norvegicus ◽  
Interference Competition ◽  
Species Abundance ◽  
Late Summer ◽  
Baseline Data ◽  
Individual Species ◽  
Competitive Interference ◽  
Norway Rats

Norway rats (Rattus norvegicus) are sympatric with, and more often trapped, than the smaller Pacific rat (R. exulans) on Raoul Island, New Zealand. Rats were removed from a four-hectare grid by trapping and poisoning in the winters of 1994, 1995 and 1996. Pacific rats were trapped in increasing numbers only after Norway rats were removed. Norway rats also ate significantly more bait than Pacific rats. Competitive interference of Pacific rats by Norway rats was apparent, which casts doubt on the ability to accurately monitor individual species abundance within assemblages of rat species and to effectively manage them in control grids. Snap-trapping lines provided baseline data on the abundance of the two species before, during and after the removal grids were operated. Maximum abundances of rats were recorded in late summer and autumn following spring and summer breeding.

Differences in Susceptibility to Predation during Nesting Between Pied and Black Stilts (Himantopus spp.)

The Auk ◽  
1986 ◽  
Vol 103 (2) ◽  
pp. 273-280 ◽  
Author(s):  
Raymond J. Pierce
Keyword(s):  
New Zealand ◽  
Breeding Success ◽  
Site Fidelity ◽  
Indirect Evidence ◽  
Nesting Success ◽  
Nest Failure ◽  
Foraging Patterns ◽  
High Site ◽  
Breeding Seasons ◽  
The Impact

Abstract The nesting success of the Pied Stilt (Himantopus himantopus leucocephalus) and the endangered Black Stilt (H. novaezealandiae) was studied for three consecutive breeding seasons (1977-1979) in New Zealand. Black Stilts had a breeding success of less than 1%, compared with over 8% for Pied Stilts. Predation by feral mammals was the main cause of nest failure for both species, but the impact was greater on Black Stilts. Direct and indirect evidence (including trapping predators) suggests that these introduced ground predators kill many chicks. Several factors made Black Stilts vulnerable, particularly their nesting along stream banks that were often frequented by predators; Pied Stilts nested in swamps where predators were few. Black Stilt chicks took up to 2 weeks longer to fledge and their foraging patterns made them more vulnerable than Pied Stilt chicks. Other factors that possibly increased predation risk of Black Stilts include nesting at times of high predator activity, solitary nesting, high site fidelity, ineffective distraction displays, and lack of a disruptive camouflage pattern in adults. Introduced ground predators probably have contributed greatly to the decline of Black Stilts. Pied Stilts have not been affected similarly, because their evolutionary past has included long exposure to ground predators.

scholarly journals Comparative effects of brodifacoum on rats and possums

2000 ◽  
Vol 53 ◽  
pp. 310-315 ◽  
Author(s):  
K.E. Littin ◽  
C.E. O'Connor ◽  
C.T. Eason
Keyword(s):  
New Zealand ◽  
Rattus Norvegicus ◽  
Blood Clotting ◽  
Species Differences ◽  
Trichosurus Vulpecula ◽  
Pathological Changes ◽  
Clotting Factors ◽  
Norway Rats ◽  
Blood Clotting Factors

The anticoagulant brodifacoum is widely used overseas as a rodenticide and in New Zealand to control rodents and brushtail possums (Trichosurus vulpecula) The efficacy behavioural and pathological changes and times to death were compared between Norway rats (Rattus norvegicus) and brushtail possums poisoned with brodifacoum Caged animals were given brodifacoum in wax or cereal baits observed for signs of toxicosis and changes in behaviour then autopsied after death Brodifacoum caused haemorrhaging and death in both species and although each showed marked changes in behaviour and pathology they differed in character time of onset and duration Results may be explained in part by species differences in behaviour and halflives of blood clotting factors

scholarly journals Immediate and long-term effects of translocations on breeding success in Takahe Porphyrio hochstetteri

2003 ◽  
Vol 13 (4) ◽  
pp. 299-306 ◽  
Author(s):  
Ian G. Jamieson ◽  
G. Craig Wilson
Keyword(s):  
New Zealand ◽  
Breeding Success ◽  
Habitat Suitability ◽  
Conservation Management ◽  
Model System ◽  
Breeding Birds ◽  
Long Term Effects ◽  
Island Populations ◽  
Number Of Individuals

Translocations of threatened species play an increasingly important role in conservation management. However, few studies have examined what effects, if any, the translocation process itself (i.e. catching, handling, confining, transferring and releasing an animal into an unfamiliar environment) has on subsequent breeding success. Takahe Porphyrio hochstetteri living on offshore “predator-free” islands in New Zealand are a model system for examining such effects because pre-breeding birds have been frequently translocated between established island populations before they pair up and breed at 2-3 years of age. We postulated that “translocated” breeders (i.e. breeders that had been raised on another island) would delay first breeding attempts and/or have lower reproductive success compared with “resident” birds (i.e. bred on the same island that they were raised). The results indicated that translocated birds did not delay breeding and had similar mean hatching and fledging success as resident pairs in their first breeding season and subsequent seasons combined. The results suggest that at least for large or long-lived birds such as Takahe, the effects of any stress from the translocation itself, or the release into an unfamiliar environment, might be either short-lived or not significant enough to hinder subsequent breeding success. We recommend that further research be carried out on other species to determine the baseline effects, if any, of translocations, so that they can be taken into account when considering other determinants of translocation success such as habitat suitability, number of individuals and timing of releases.

Causes of mortality of Black-fronted Terns Sterna albostriata on the Ohau River, South Island, New Zealand

2002 ◽  
Vol 8 (3) ◽  
pp. 170 ◽  
Author(s):  
Rachel J. Keedwell ◽  
Mark D. Sanders ◽  
Maurice Alley ◽  
Caroline Twentyman
Keyword(s):  
New Zealand ◽  
Road Traffic ◽  
Population Decline ◽  
Predator Control ◽  
Predator Species ◽  
Video Footage ◽  
Physical Evidence ◽  
Causes Of Mortality ◽  
Breeding Seasons ◽  
Norway Rats

We examined the carcasses of 148 Black-fronted Terns Sterna albostriata found during the 1998-2000 breeding seasons on the Ohau River, South Island, New Zealand. Predation was the primary cause of mortality of adults, juveniles and chicks, resulting in 47% of all deaths. Video footage showed Feral Cats Felis catus were responsible for 6% of all predator-caused deaths, and physical evidence at carcass remains linked cats to another 19% of predations. Further evidence suggested Norway Rats Rattus norvegicus and Stoats Mustela erminea were responsible for 51% and 6% of predator-caused deaths, respectively. The prey remains left by the different predator species are described. Other causes of mortality included starvation (4%), power lines (1%), road traffic (1%) and various natural causes of mortality (5%). Causes of mortality could not be assigned to 41 % of Black-fronted Terns, but most of these were young chicks that died at the nest soon after hatching. We suggest that predators are potentially the main cause of population decline in black-fronted terns and that predator control targeting cats and Norway Rats during the breeding season should be trialled.

scholarly journals Field trials of flocoumafen against warfarin-resistant infestations of the Norway rat (Rattus norvegicus Berk)

1986 ◽  
Vol 96 (3) ◽  
pp. 467-473 ◽  
Author(s):  
A. P. Buckle
Keyword(s):  
Rattus Norvegicus ◽  
Field Trials ◽  
Anticoagulant Rodenticide ◽  
Complete Control ◽  
Norway Rat ◽  
Norway Rats ◽  
Farm Buildings

SUMMARYThe anticoagulant rodenticide flocoumafen was tested against warfarin-resistant Norway rats (Rattus norvegicus Berk.) infesting farm buildings. Complete control was obtained in 10–21 days (mean 14·2 days) in six treatments in which baits poisoned with 0·005% flocoumafen were maintained, in surplus, until rats ceased to feed from them. A further six treatments, in which the application of poisoned bait was restricted to periodic placements of 50 g, were also completely successful in 15–30 days (mean 21·0 days). Less poisoned bait was used in the restricted flocoumafen treatments than in the unrestricted treatments but the time taken to control the rat infestations was significantly longer.

Do Norway rats (Rattus norvegicus) synchronize their estrous cycles?

2001 ◽  
Vol 72 (1-2) ◽  
pp. 129-139 ◽  
Author(s):  
Jeffrey C Schank
Keyword(s):  
Rattus Norvegicus ◽  
Estrous Cycles ◽  
Norway Rats

scholarly journals Factors that Encourage Student Engagement: Insights from a Case Study of ‘First Time’ Students in a New Zealand University.

2011 ◽  
Vol 8 (1) ◽  
pp. 81-96
Author(s):  
Barbara Russell ◽  
◽  
Gloria R L Slater ◽  
Keyword(s):  
New Zealand ◽  
Student Engagement ◽  
Conceptual Model ◽  
Tertiary Education ◽  
Research Question ◽  
Education Programme ◽  
Active Citizenship ◽  
Structured Interviews ◽  
First Time

This case study reports on the findings from one of nine tertiary institutions that took part in a project funded by the Teaching and Learning Research Initiative (TLRI) in New Zealand. The research question explored how institutional and non institutional learning environments influence student engagement with learning in a higher education, university setting. Data was collected initially by means of a questionnaire; subsequently more in-depth data was gathered through semi-structured interviews with students randomly selected from those who indicated, on the questionnaire, that they were willing to be interviewed. Respondents were enrolled for the first time in this institution, but not necessarily for the first time in a tertiary education programme. A conceptual model with four strands: motivation and agency; transactional engagement; institutional support and active citizenship was used to organise the data. Findings were analysed against a synthesis of current literature and suggest that factors identified in the first three strands of the conceptual model played a significant role in student engagement with learning; active citizenship, however, did not feature highly in student responses and is an aspect of engagement that could benefit from further research.

scholarly journals Breeding success and causes of breeding failure of curlewNumenius arquatain Northern Ireland

1999 ◽  
Vol 36 (1) ◽  
pp. 59-74 ◽  
Author(s):  
Murray C. Grant ◽  
Chris Orsman ◽  
Jon. Easton ◽  
Chris Lodge ◽  
Malcolm Smith ◽  
...  
Keyword(s):  
Northern Ireland ◽  
Breeding Success ◽  
Breeding Failure
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