Stoats

Source Author Year Title Quote
TV3News online 29/01/14 Simon Wong 2014 Expanded 1080 drop to curb ‘plague’ of rats “Dr Smith says it is “particularly urgent” this year because there is a one-in-10 year beech mast in which beech trees will drop a million seeds in autumn. “This flood of food will trigger a plague of an additional 30 million rats and tens of thousands of stoats,” Dr Smith says. “When the seeds germinate in spring, these starved predators will annihilate populations of our endangered birds””
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “This includes new standards to achieve effective control of stoats with all aerial 1080 operations, so that any potential kea deaths are offset by improved productivity and survival.”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “By designing operations to control stoats, we can reverse the decline of kea at managed sites”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “Kea were re-classed from ‘Not threatened’ to “Nationally endangered” by Robertson et al. (2012); the criteria for this classification are a population estimate of 1000-5000 and an ongoing or predicted decline of 50-70% in the total population over the next 10 years due to recruitment failure. In order to prevent this failure, effective predator control is critical.”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “Kemp et al. (2014 [unpublished]) identified the key predators of kea using a combination of nest cameras, corpse necropsy and inference from predator density fluctuations during nest survival monitoring. Nest cameras recorded visits by stoats, possums, ship rats, house mice and weka. Stoats were identified as the predator in 3 of the 16 nest failures…Two predation events were confirmed by corpse necropsy; one death by stoat predation was confirmed by DNA analysis and the other was predated by a falcon or a stoat…control needs to take place on a landscape scale to protect kea predation by stoats”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “However stoats are a far more important predator, particularly following mast events when kea nest failure and predation of juveniles and adults are at their greatest.”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat, dispersal “Kea breeding pairs and nests are found at low density (Jackson 1960) so broad scale control is needed to cover even a small number of nests…Stoats have a large home range and dispersing young are capable of long distance travel…so localised small scale control measures are quickly undone by immigration…an extensive area must be controlled to [sic] when stoats are targeted”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “Aerial application of 1080 baits…can be effective for reducing stoat numbers…data on mouse kill from aerial 1080 cereal pellet operations appears to be variable, although we don’t know if this will affect stoat kill…if rats aren’t present in a forest, such as at high altitudes or in pure beech forests we are unsure of the extent of the stoat by-kill.”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “In order to make up for the few adult kea sometimes killed in aerial 1080 cereal operation, all operations should be designed to achieve stoat control”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “What if we plan our operation for June or July, but sustained poor weather means that we miss this deadline? The intention is to achieve stoat control prior to kea nesting…but if this deadline is still not met, the operation should proceed as early as possible.”
Scoop Independent News 22/5/14 Murray Dench 2014 Why is there an argument over 1080? “We know that stoats eat rats, lots of rats, but their population recovery after a poison operation is delayed by a process called delayed implantation…Mating occurs in early summer, but births do not occur until the spring of the following year…This extremely long lag phase in the stoat population growth curve gives the rats a huge head start in developing a population.”
Tbfree New Zealand Ltd AEE TBFree 2014 Assessment of Environmental Effects for Possum Control in the Barton Arthur Area May 2014 “Nationally threatened bird species recorded in or near the operational area are kaka, kea, and New Zealand falcon…These threatened species are potentially at risk from the operation considering the risk that the number of non-target deaths might push the total numbers into a decline from which recovery is difficult…The possible impacts of this operation on the kea population are considered to be negligible compared to the potential benefits accruing from the reduction in rat, stoat and possum predation.”
Otago Daily Times Online News 06/04/14 Rebecca Fox 2014 Research aids kea conservation “Nationally endangered, keas have a population of fewer than 5000 that is in decline due to predation by pests such as rats, mice and stoats.”
Otago Daily Times Online News 13/10/14 Matthew Haggert 2014 Health of kea studied “A drop in kea population numbers has left Doc Wanaka biodiversity manager Stu Thorne “slightly” concerned…There had been no aerial drops of 1080 in their habitat around Wanaka, he said. Seven kea were given blood tests during the recent monitoring programme and the results all indicated “low to very low” levels of lead. Mr Thorne ruled out contact with people visiting the skifield as a possible cause of a decline in kea numbers. “There’s probably not any one single cause contributing to a decline, but I do think a growth in predator numbers could be significant. The presence of stoats in the alpine areas and “vulnerable” kea nesting habitats could be having an effect, he said”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “A previous standard has been removed, which prevented baits from being sown in areas of low structural vegetation cover (eg alpine herb fields and tussock) above the tree line. This was intended to protect kea by keeping baits out of open areas that could be easily avoided. Subsequent kea deaths at Okarito and Otira suggest that most kea ignore 1080 pellets but a small number will find and eat them whether they are highly visible or not”. This draws into question the effectiveness of the alpine exclusion standard. At the same time, a need for predator control in alpine environments is emerging (O’Donnell 2013). Stoats and mice are prevalent predators in the alpine zone and possums are significant predators of snails.”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “Standard 4: Toxic bait application can occur when either (a) or (b) are met: (a) Within 6 months prior to the operation, the tracking index for rats is 20% or higher…(b) Within 6 months prior to the operation, the tracking index for mice is 20% or higher…Stoats do not eat 1080 baits but can be poisoned when they prey on rats (and possibly mice and possums) that have taken bait.”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “…stoats are the main predators of kea.”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “Do we need to comply with the ‘performance standards to ensure kea benefit from stoat control?…Any decision to exempt a DOC permission from the Code is at the discretion of the approving manager…”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “Operations need to occur when rodents are widespread…At Mt Arthur, the operation took place in May 2009, when rodent numbers were still climbing…Monitoring showed that the stoat irruption was not prevented…several adult kea disappeared and no kea nests were found despite extensive searches”
DoC 07/05/2014 DoC 2014 DOC code of practice for aerial 1080 in kea habitat “Effective stoat control appears more likely where rats are widespread in the operational area…The transition from prevalent to low rat densities is likely to happen somewhere between 500m and 700m in mixed forests depending on the site and season.”
Scoop Independent News 22/5/14 Murray Dench 2014 Why is there an argument over 1080? “A hint of the problem was given to me by John Innes of Landcare Research many years ago during a lecture on tui habitat enhancement. John used a whiteboard to list the three most important predators of our native bird species and he wrote them up on the board in the following order of importance:- RATS RATS RATS. What he was explaining, in a very effective way, was that although cats take some birds, as do possums, stoats, myna and a variety of other species, they don’t come close to rats as the major predator of native birds.”
Scoop Independent News 22/5/14 Murray Dench 2014 Why is there an argument over 1080? “These results suggest that the huge sustained increase in rat abundance following initial possum control in 1994 was reversed by further control in 2000. Since then rat populations have increased rapidly. This increase may have serious consequences not only for native species preyed on by rats but also for native species threatened by stoats or cats as both these predators may increase when rats (a major element in their diet) are very abundant. (Quote from He Korero Paihama, June 2002)”
Kea Conservation Trust updates 16/12/13 Kea Conservation Trust 2013 Kea Conservation Trust (KCT) Update “…released at Canaan Downs (named Asterix) has died as the result of getting caught in a stoat trap. Aterix’s body was found by trapping volunteers (who were obviously most upset) on the 13th November. It appears that he managed to pry the screwed down lid off the trap to gain access. A warning has been sent out to other trapping groups in kea habitat to check their lids are secured firmly.”
Kea Conservation Trust updates 16/12/13 Kea Conservation Trust 2013 Kea Conservation Trust (KCT) Update “At Nelson Lakes, “Ceejay” is still sitting on 1 chick (pictured to the right)…and Rachel is sitting on 2 chicks. If both nests are successful, it will be the first time that more than one nest per year has avoided predation. Both nests are surrounded by a network of stoat and possum traps…which may be contributing to this success”
Kea Conservation Trust updates 16/12/13 Kea Conservation Trust 2013 Kea Conservation Trust (KCT) Update “Bucket died in a stoat trap – she was a victim of her own intelligence and curiosity and we were devastated when we lost her. She was the matriarch of the colony – I will never forget the year she fledged two of the healthiest young I have ever seen…”
DoC G. Harper et. Al. 2013 Rotoiti Nature Recovery Project Annual Report 2011-12 “On-going mustelid trapping in the Mainland Island kept the mustelid tracking indices below 4% during 2011-12, whist tracking at the non-treatment site at Lake Rotoroa exceeded 22%.”
DoC G. Harper et. Al. 2013 Rotoiti Nature Recovery Project Annual Report 2011-12 “During 2011-12, mustelid tracking rates were again below 5%…highlighting the ability of the form of trapping programme being used to maintain pressure on an invasive predator population”
www.keaconservation.co.nz 22/11/2013 T. Orr-Walker 2013 Nest Monitoring “…the reason for lack of fledglings was attributed to predation of nests by introduced stoats and possums.”
Otago Daily Times Online News 02/07/2012 Mark Price 2012 Kea using sticks as tools “…kea in Fiordland had been observed grasping sticks in their powerful beaks and triggering stoat traps with them. That way, the “cheeky” mountain parrots were able to get their beaks on the egg used as bait in the trap…The unfortunate irony is that the traps are set to protect kea nests from predation by stoats.”
Kea Conservation Trust Updates Dec 2012 T. Orr-Walker 2012 Field Projects – Nest monitoring updates “Photos: Hawdon Valley Nests: A stoat is caught on the scout camera outside Hows nest and 2 chicks remaining in Queen Powpows nest from and original 3 chicks.”
NZ J Ecology 36: 131-140 C. O’Donnell & J. Hoare 2012 Quantifying the benefits of long-term integrated pest control for forest birds populations in a New Zealand temperate rainforest “Stoats were caught in relatively high numbers in four of the 10 years…Three of these years coincided with partial or full beech mast…but captures were low after the partial mast of 2003.”
Kea Conservation Trust Updates Dec 2012 T. Orr-Walker 2012 “Research with Impact – KCT winners at Unitec “A piece of research supported and funded by the KCT recently won the prize for the “Research with Impact” at the recent Unitec Research Symposium. The presentation…highlighted the likely effect of introducing bird repellents to reduce mortality of kea during aerial 1080 poison drops to control stoats, possums and rat populations…this was the research that was most clearly identified to have an impact on practice.”
NZ J Ecology 36: 131-140 C. O’Donnell & J. Hoare 2012 Quantifying the benefits of long-term integrated pest control for forest birds populations in a New Zealand temperate rainforest “An inventory of the forest bird population of the Landsborough Valley was conducted in 1985…The inventory noted significant bird populations in the valley, including the largest population of mohua…in the region…The site was recommended for protection…At the time, research indicated that predation by stoats (Mustela erminea) was a major cause of decline in mohua populations throughout the South Island, and that, for populations to be maintained or recover, predator control at those sites would be required.”
www.1080science.co.nz 2011 A scientific evaluation of the Parliamentary Commissioner for the Environment’s Views on 1080 “Expected effects of aerial 1080 poison on pests include abundant mice, and cats and mustelids switching their prey from rats (or rabbits) to invertebrates, birds and reptiles.”
DoC Operational Report DoC 2011 Operational Report for Possum, Ship rat Control in the Otira Possum Control 16 Jun 2011 – 30 Jun 2011 “The reduction in rats, the main prey of stoats, may lead to an increase in stoat predations on birds. The increase in mice may counter this to some degree if stoats switch to mice as their main prey item. In the short term resident stoats will die from feeding on dead possums and rats but this benefit will not be sustained, as stoats will rapidly re-invade the area. The abundance of introduced birds is more likely to form the bulk of stoat prey until rats become more plentiful again”
Arthur’s Pass Wilderness Lodge 12/12/11 2011 The Wilderness Lodges – A great place to view New Zealand’s parrots “At Arthur’s Pass, our own pest control programme over 1000 hectares…has dramatically reduced the number of rats, stoats and possums. We see yellow-crowed kakariki feeding on beech forest seeds and flowers all around the lodge. As at Lake Moeraki, Kea are abundant around the lodge and in the wider Arthur’s Pass”
Otago Daily Times Online News 12/09/11 Otago Daily Times Online News 12/09/11 2011 Seven keas dead in the wake of 1080 work “Then conservation minister Steve Chadwick maintained the poison was still the best tool for protecting native forests from the ravages of possums, rats and stoats”.
Otago Daily Times Online News 12/09/11 Otago Daily Times Online News 12/09/11 2011 Seven keas dead in the wake of 1080 work “The recent aerial 1080 operation was three years in planning and jointly run by the Animal Health Board and DoC. It covered 30,000 ha, including the South Okarito kiwi sanctuary, North Okarito forest, and a large forested buffer zone around Franz Josef township. The operation intended to protect New Zealand’s rarest kiwi – the rowi – from rats, stoats and possums, as well as protecting local farms from the threat of bovine tuberculosis”
www.1080science.co.nz 2011 A scientific evaluation of the Parliamentary Commissioner for the Environment’s Views on 1080 “Aerially spread 1080 poison will only reduce numbers of rats for a few months, beyond which a steep increase in numbers is expected. Repeated aerial poisonings of rats are likely to become less effective. Stoat numbers are not likely to be reduced by aerial 1080 for any significant amount of time. Rats and stoats need continuous, rather than pulsed control and a variety of control techniques.”
NZ J Ecology 34: 272-273 D. Armstrong et al. 2010 Impacts of pathogenic disease and native predators on threatened native species. “mice are so far the Achilles heel of many programmes, with mouse numbers irrupting following rat and/or stoat removal.”
The adventures of PK Maebo & Jimjam 9/2/09 Jaimie Stewart 2009 A day out in Okarito “She gave us a map and some instructions to follow some old stoat trap lines and find these little ink pad things which record nasty voracious predators have been passing by….The map is fascinating, and graphically shows what a unique area the Okarito forest is…The dense rimu forest has provided sanctuary to the final population of Rowi and people have helped buffer the defences in the last ten years or so…Interestingly the article states that the ‘stoat trapping operation in this sanctuary is thought to be the largest in the world’. The extensive network of tracks and dots (representing traps) enabling this operation can be seen on the map we used….A decision has been made now to mothball the trapping programme, relying instead on strategic use of 1080, which is why Franny and Brent are here…But what is left is an amazing network of tracks”
Forest & Bird The Green Room Forest & Bird 2009 Keas for Keeps “the presence of these young birds seen today shows that without the disastrous impact of stoats and possums that kill most kea chicks on their nests, our Southern South Westland keas here are prospering”
Forest & Bird The Green Room forum 2009 Forest & Bird 2009 Keas for Keeps “…the presence of these young birds seen today shows that without the disastrous impact of stoats and possums that kill most kea chicks on their nests, our Southern South Westland keas are prospering.”
NZ J Ecology 29: 69-82 D. Kelly et al. 2005 Can stoat (Mustela erminea) trapping increase bellbird (Anthornis melanura) populations and benefit misteltoe (Peraxilla tetrapetala) pollination? “…the Department of Conservation carried out a small experimental programme in the treatment area using cholecalciferol-poisoned eggs”
NZ J Ecology 29: 69-82 D. Kelly et al. 2005 Can stoat (Mustela erminea) trapping increase bellbird (Anthornis melanura) populations and benefit misteltoe (Peraxilla tetrapetala) pollination? “…saturation of predators and consequent reduced predation rates on birds is now thought to occasionally occur when mice reach extremely high densities (C.M. King, pers. comm., Waikato University, Hamilton, N.Z.).”
NZ J Ecology 29: 69-82 D. Kelly et al. 2005 Can stoat (Mustela erminea) trapping increase bellbird (Anthornis melanura) populations and benefit misteltoe (Peraxilla tetrapetala) pollination? “Several studies on other forest birds have found that trapping can reduce the high predation pressure during stoat irruptions. O’Donnell et al. (1996) found that a very intensive trapping programme significantly reduced stoat predation on breeding mohua during a stoat irruption.”
NZ Dept of Conservation Internal Science Series 181 Graeme Elliot & Josh Kemp 2004 Effect of hunting and predation on kea, and a method of monitoring kea populations “…there is no reason to suppose that stoat numbers have changed”
Science for Conservation 237 J. Parkes & E. Murphy 2004 Risk assessment of stoat control methods for New Zealand “Kill-trapping is currently the main stoat control method used by DOC covering c. 100 000 ha in 51 mainland operations…”
Science for Conservation 237 J. Parkes & E. Murphy 2004 Risk assessment of stoat control methods for New Zealand “The advantages of traps are that they are a proven technique that can reduce stoat numbers sufficiently to protect native biota, e.g. In mainland…”
Science for Conservation 237 J. Parkes & E. Murphy 2004 Risk assessment of stoat control methods for New Zealand “The main risk in the use of traps is that the most commonly used ones (Fenn Mk 4 and Mk6) do not meet the national Animal Welfare Advisory Committee (NAWC) draft guidelines for humaneness…”
Science for Conservation 237 J. Parkes & E. Murphy 2004 Risk assessment of stoat control methods for New Zealand “The toxins currently used in New Zealand are only registered for the target pest, generally possums, so the deliberate use of them to target stoats is illegal. Although a high percentage of stoats may be killed initially by secondary poisoning, the effect is likely to be short-lived because control aimed at the primary pest is often too infrequent to provide anything but short-term control of stoats given their ability to reinvade treated areas”
NZ Dept of Conservation Internal Science Series 181 Graeme Elliot & Josh Kemp 2004 Effect of hunting and predation on kea, and a method of monitoring kea populations “Eggs and chicks disappeared from 35% of the nests we monitored and at two of these nests definite sign of stoat predation was found”
NZ Dept of Conservation Internal Science Series 181 Graeme Elliot & Josh Kemp 2004 Effect of hunting and predation on kea, and a method of monitoring kea populations “The main   potential predators of kea nests in montane beech forests in the northern South Island are stoats and possums…The only nest failure we can confidently attribute to a specific predator was caused by a stoat”
Science for Conservation 237 J. Parkes & E. Murphy 2004 Risk assessment of stoat control methods for New Zealand “Controlling primary prey can cause stoats to alter their diet to consume more secondary prey (often native species) and so, at least in the short term, cause more harm than good.”
Rarebits 52 DoC 2004 Newsletter “The stoat control line in the Landsborough Valley has recently been extended down to Harper Flat, just above the confluence with the Clarke River. There are now 189 tunnels with two traps per tunnel in the valley, with 41 of these on the recent extension…Following a beech mast in 2000 and corresponding stoat plague in 2001, stoat numbers have steadily declined in 2002/03. Seven stoats were caught over a 10 week period this year compared with 23 from the same period in 2001”
Rarebits 44 DoC 2002 Newsletter “Four months after an effective possum and rat knock-down by a 20,000-ha aerial 1080 operation over Tongariro Forest, stoats reappeared in the centre of the forest and began killing kiwi chicks. So far five of the 11 chicks have been predated, and all in the centre of the treatment area…Rodent numbers remain surprisingly low, with the same tracking index recorded in February as in December (< 2.0%).”
Rarebits 44 DoC 2002 Newsletter “Over the last six seasons, mohua productivity and numbers were increasing as a result of stoat control, however rat plagues are a new phenomenon for DOC in the South Island with swift and catastrophic impacts… This season, two breeding pairs produced three fledglings each, and one pair produced one fledgling. This nearly doubles the population of survivors – a small victory for mohua in the face of such adversity”
Rarebits 46 DoC 2002 Newsletter “Okarito Kiwi Zone: The results from the rodent lines in March show that there has been a huge increase in rat abundance between March (3.5% tracking index) and August (80% tracking index). This correlates with our casual observations from the stoat trapping program which have indicated a much higher rat trapping rate than previously. We have also been noticing the capture of lactating female rat’s right throughout the winter months. It seems that rat numbers are higher within the sanctuary (80% tracking rate) as opposed to in the two areas in which do not have stoat trapping (38.6%)…Since May 2001 there have been a total of 605 stoats caught.”
DOC Science Internal Series 107: 16 pp D. Smith & I. Jamieson 2003 Movement, diet, and relative abundance of stoats in an alpine habitat “A prey switch to ground weta occurred as mice numbers declined, and not to birds, as is often expected or feared by conservation managers.”
DOC Science Internal Series 107: 16 pp D. Smith & I. Jamieson 2003 Movement, diet, and relative abundance of stoats in an alpine habitat “As mice numbers rise after beech masts, the stoat population also increases and uses mice to maintain population growth. When mouse numbers crash, stoat numbers also decline, with the small number of remaining stoats in the Murchison Mountains apparently relying primarily on ground weta for their survival.”
DOC Science Internal Series 107: 16 pp D. Smith & I. Jamieson 2003 Movement, diet, and relative abundance of stoats in an alpine habitat “…peaks in stoat activity seem to be in late summer and autumn.”
Tuberculosis 81: 191-202 J.D. Coleman, M.M. Cooke 2001 Mycobacterium bovis infections in wildlife in New Zealand “Tuberculosis has been recorded in a small number of stoats …Disease prevalences are unknown, and estimates of them are difficult, due to the rapid turnover of stoat populations and difficulty in trapping them.”
Tuberculosis 81: 191-202 J.D. Coleman, M.M. Cooke 2001 Mycobacterium bovis infections in wildlife in New Zealand “All of these species are potential hosts of M. Bovis, and the disease has been recorded in at least 14 of them, including free-living possums, hedgehogs, a rabbit, hares, stoats, ferrets, cats, pigs, cattle, goats, sheep, red deer, sika deer, and fallow deer”.
Tuberculosis 81: 191-202 J.D. Coleman, M.M. Cooke 2001 Mycobacterium bovis infections in wildlife in New Zealand “The mode of transmission between possums and livestock is poorly understood and difficult to study. However, dominant cattle and deer have been observed to approach semi-sedated (“sick”) possums, and sniff and mouth them. Such exploratory behaviour is likely to expose both livestock species and presumably also wild deer to infection. It is likely that possums are also an important source of infection for ferrets, feral cats, stoats, hedgehogs, feral pigs, and other possums, which have all been recorded scavenging the carcasses of infected possums.”
Conservation Advisory Notes 318, 9pp. B. Studholme 2000 Ship rat (Rattus rattus) irruptions in South Island beech (Nothofagus) forest In 1985 a remnant population of mohua (yellowhead) was discovered in silver beech (Nothofagus menziesii) forest on Mt Stokes in the Marlborough Sounds. Over recent years, intensive pest control has been carried out on the mountain for possums, stoats, weasels, goats and pigs…However, over the winter of 1999, more than half of these birds went missing. Only 32 birds could be found in October 1999…Stoats and ship rats were caught on Mt Stokes traplines in October 1999…Few ship rats had been caught in these traplines previously…this high-altitude beech forest was thought to be unsuitable habitat for ship rats…Low numbers of stoats were caught on the mountain in 1997/98…and a beech mast seedfall occurred in autumn 1999. Reduced predation pressure and an increased food supply, coupled with a mild winter, may have contributed to increased ship rat numbers on the mountain.”
Conservation Advisory Notes 318, 9pp. B. Studholme 2000 Ship rat (Rattus rattus) irruptions in South Island beech (Nothofagus) forest “It is likely that seeedfall is only one of the factors regulating ship rat numbers in beech forest. There are some examples where ship rat numbers do not increase after beech seedfall. A partial mast in the Dart and Caples Valleys last autumn (1999) did not result in high rat numbers…King (1983) recorded an increase in rat numbers in the Hollyford and Eglinton valleys after seed fall in 1996 but found no increase after a beech mast in 1979.”
Conservation Advisory Notes 318, 9pp. B. Studholme 2000 Ship rat (Rattus rattus) irruptions in South Island beech (Nothofagus) forest “…ship rats were not an important food for stoats in the Hollyford and Eglinton Valleys even in years of relatively high rat abundance (King & Moller 1997).”
Conservation Advisory Notes 318, 9pp. B. Studholme 2000 Ship rat (Rattus rattus) irruptions in South Island beech (Nothofagus) forest “In January 2000, P. Gaze (pers. Comm.) found the abundance of mice of Mt Stokes to be thirty times greater in those areas subject to stoat control, indicating stoats were a major limiting factor on mouse numbers.”
Conservation Advisory Notes 318, 9pp. B. Studholme 2000 Ship rat (Rattus rattus) irruptions in South Island beech (Nothofagus) forest “Stoat trapping on Mt Stokes and at Craigieburn Forest Park has not lowered the threshold to ship rats on its own, because otherwise ship rats would have established in the area by now. However, in conjunction with other factors, i.e. an increase in food supply, stoat trapping might have lowered the threshold significantly to allow rats to survive in areas of marginal habitat.”
Conservation Advisory Notes 318, 9pp. B. Studholme 2000 Ship rat (Rattus rattus) irruptions in South Island beech (Nothofagus) forest “Elliot (1990) observed that Mohua have survived for over 100 years of rat and stoat predation in beech forest where rat abundance is generally low with only occasional peaks”
Rarebits 36 DoC 2000 Newsletter “The Mt Stokes mohua population has dropped dramatically. At the end of the 1998-99 summer there were around 90 birds, but now numbers are estimated at 27, of which only 6 are female. Predation by ship rats is thought to be the cause of the sudden decline… Intensive trapping of stoats had been sufficient to protect the birds because rats had almost never been recorded at this altitude on Mt Stokes.”
Rarebits 36 DoC 2000 Newsletter “As introduced predators are displaced it would appear native predators are making the most of the opportunity, e.g. a pair of NZ falcon known to have nested in the reserve.”
Rarebits 38 DoC 2000 Newsletter “low intensity stoat control has been undertaken using Mk VI Fenn traps…It appears that stoat control carried out at this low intensity provides sufficient protection to markedly reduce stoat predation on breeding mohua and kaka… This summer we may not have lost any nests to stoats, but the huge increase in rat numbers and the associated rat predation is a major concern… If a permanently higher rat population were a result of continual stoat trapping, there would be serious consequences for many bird species. It could be suggested that stoat trapping be initiated only following beech mast years, but for kaka, at least, stoat control would need to occur during the previous summer when beech flowering initiates widespread breeding…To keep the stoat population at a low level with a low density of traps probably requires continual trapping. Further work is needed here on rat population dynamics in beech forests to determine whether lack of predators means a larger irruption in mast years or if climate is the major influence.”
Rarebits 38 DoC 2000 Newsletter Blue Mountains mohua: 12 stoats were caught in 35,280 corrected trapnights (CTN). Over the five summers that the lines have been operated the number of stoats caught tallied 13, 6, 12, 5, and 12 respectively. Because of the extremely heavy beech seedfall of the preceding autumn and the predicted consequent mouse and stoat plague, a further three trap lines were installed in and about an area with a particularly high Mohua population. These lines were operated over November and December only and accounted for 11 stoats in 13,556.5 CTN. Given that the mouse index trapping undertaken in November 1999 resulted in a 33-fold increase in numbers caught compared with any of the preceding 5 years, the lack of a significant increase in the number of stoats caught was somewhat unexpected. Therefore one tends to the conclusion that for reasons unknown in the Blue Mountains there is a low population of stoats and/or that a stoat irruption does not necessarily follow a major beech mast year and a subsequent significant increase in mouse numbers.”
Rarebits 38 DoC 2000 Newsletter “At Otamatuna, stoat control has resulted in 70% of monitored kiwi chicks surviving to over 1000 g (the ‘stoat-proof’ weight) during the past 4 years of management. This compares to a 5% survival rate in other unmanaged North Island sites. A breakthrough in stoat control developed by NTUERP may have been achieved using freeze-dried rats as a lure to trap stoats. When placed under a plastic cover these rats have remained effective in trapping stoats for up to 6 weeks under field conditions. Two hundred and eighty tunnels each containing two Fenn traps were set along 42 km of lines on ridges, spurs and streams covering 1500 ha. The tunnels were alternately lured with a freeze-dried rat and plastic egg (which, along with hen eggs, are currently the best longlasting stoat lure) in one tunnel, followed by a plastic egg in the next. Over a 3- month period 57 stoats were caught. Fifty (88%) were caught in tunnels containing the freeze-dried rats, which is significantly higher than the number caught using plastic eggs alone (p<0.001, Fischer’s exact test).”
Rarebits 39 DoC 2000 Newsletter Whio: Two of the three videoed nests have been visited by stoats and one also by a possum. A stoat destroyed one of the nests and the female survived, while the other female managed to defend her nest from a stoat and a possum although the stoat stole one egg. A third female was thought to have just begun incubating when she was killed, she was found pulled under a rock with stoat scats surrounding her.”
Rarebits 39 DoC 2000 Newsletter “Mohua/predator control: Rat captures in the Makarora and Dart Valleys are up on previous years, and rodents now appear to be a permanent feature of these permanent trap lines. Also, in the Dart stoat numbers are increasing as a result of the mast event last spring. This is the third season in a row for high stoat numbers in the Dart.”
Rarebits 40 DoC 2000 Newsletter “The apparent loss of the Mt Stokes mohua has been devastating. Numbers increased spectacularly with stoat control over the past 10 years, but an unprecedented irruption of ship rats during the winter of 1999 spelt their doom.”
Rarebits 40 DoC 2000 Newsletter “Trap lines for stoats in the Makarora Valley continue to catch stoats. Recently numbers are dropping off, and the rate of rat captures is increasing slightly.”
NZ J Ecology 23: 95-100 E.C. Murphy & J.E. Dowding 1995 Ecology of the stoat in Nothofagus forest: Home range, habitat use and diet at different stages of the beech mast cycle “Seedfall in Nothofagus forest is synchronous and periodic. Following seedfall, mouse density rises dramatically, followed by a sharp rise in stoat numbers. It has been suggested that mice feed on the abundant seed and that stoats in turn increase because of the large numbers of mice available to them. We suggest that the situation is more complex and that increases in not only mouse, but also bird (and possibly invertebrate) densities may contribute to the high productivity of stoats in the year following a Nothofagus seedfall.”
NZ J Ecology 23: 95-100 E.C. Murphy & J.E. Dowding 1995 Ecology of the stoat in Nothofagus forest: Home range, habitat use and diet at different stages of the beech mast cycle “Our finding that a juvenile female (probably pregnant) dispersed at least 65 km within four weeks is of particular concern from a conservation perspective. Clearing stoats from sensitive areas (and even from large buffer zones around them as well) is only an effective strategy while trapping is continued; stoats may re-invade within a few weeks after trapping stoats.”
NZ J Ecology 23: 95-100 E.C. Murphy & J.E. Dowding 1995 Ecology of the stoat in Nothofagus forest: Home range, habitat use and diet at different stages of the beech mast cycle “Stoats did not eat birds less frequently when mice were abundant, a result also found by King (1983).”
NZ J Ecology 23: 95-100 E.C. Murphy & J.E. Dowding 1995 Ecology of the stoat in Nothofagus forest: Home range, habitat use and diet at different stages of the beech mast cycle “…it is likely that most possum eaten by stoats is carrion”
NZ J Ecology 23: 95-100 E.C. Murphy & J.E. Dowding 1995 Ecology of the stoat in Nothofagus forest: Home range, habitat use and diet at different stages of the beech mast cycle “In addition, stoats may pose a threat without heavy beech seedfall. Mouse and stoat numbers can rise after poor mast years…so assessing potential impacts on threatened species may require a better predictor than heavy beech seeding alone.”
MSC Thesis, Linoln University R. Brejaart 1994 Aspects of the Ecology of kea, Nestor notabilis (Gould) at Arthur’s Pass and Craigieburn Valley. “Introduced predators such as stoats (Mustela erminea) are known to prey on the kea’s only conspecific species, the kaka (Nestor meridionalis) (P.Wilson, pers. Comm., 1994), but it is not known if or how predators affect kea”
NZ J Ecology 5: 59-66 C.M. King & C.D. McMillan 1982 Population structure and dispersal of peak-year cohorts of stoats (Mustela erminea) in two New Zealand forests, with especial reference too control “Two important implications of these data for conservation are (a) kill-trapping over large areas at considerable effort (400m trap spacing) may only hasten an inevitable post-peak decline in stoat density, because the chances of capture are low and not the same for all stoats; and (b) those killed may be replaced by immigrants from over 20km away”
NZ J Ecology 5: 59-66 C.M. King & C.D. McMillan 1982 Population structure and dispersal of peak-year cohorts of stoats (Mustela erminea) in two New Zealand forests, with especial reference too control “Of the 134 stoats marked, 56 were never recaptures, and one died during tagging.”
Notornis 16: 33-44 J R Jackson 1969 What do keas die of? “During the last hundred years Keas have shared their environment with rats Rattus spp. And stoats Mustela erminea. I have found no evidence of these animals affecting Keas. ..Twice I have found a dead possum Trichosaurus vulpecula within five yards of a Kea nest. The opossum frequently chooses holes similar to a kea nest as a den and perhaps these two opossums prospected the Kea nests.