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   Rattus norvegicus (mammal)  français   
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         Management Information

    Preventative measures: Research has shown that it can often be difficult to eradicate rats from islands in the early stages of invasion, hence it is better to prevent rodents arriving on islands in the first place. Eliminating a single invading rat can be disproportionately difficult because of atypical behaviour by the rat in the absence of conspecifics, and because bait can be less effective in the absence of competition for food (Russell et al., 2005). Weihong et al. (1999) provide useful information regarding the detection of rodent species using different trapping methods and bait, Dilks and Towns (2002) published by New Zealand’s Department of Conservation discusses how to detect and respond to rodent invasions on islands.

    Physical: Trapping is often used on a local scale, however it generally fails to remove all individuals, as trap-shy animals can survive and repopulate the island (DoC, 2004).

    Chemical: Use of anticoagulant poisons is the most common method of control. On islands, eradications have been achieved by the use of poisons. However, strict quarantine is required to prevent further spread of this species to additional islands. One of the world's largest successful eradication operations was on the 3,100 hectare Langara Island in British Columbia, Canada. The eradication campaign was begun (after preparation and trials) in July 1995 and the island was declared free of rats in May 1997 (Kaiser et al., 1997). Another example of a successful rat eradication was on Kapiti Island, New Zealand (1970 ha) where "second-generation" anticoagulant poisons have been used (Empson and Miskelly, 1999). The world's largest rat eradication project to date is on Campbell Island (11,300 ha), where eradication was declared in 2003.

    Fisher et al. (2004) suggest that diphacinone especially, and also coumatetralyl and warfarin, should be evaluated in field studies as alternative rodenticides in New Zealand. Brodifacoum, the most widely used rodenticide in New Zealand currently, can acquire persistent residues in non-target wildlife. Mineau et al. (2004) discussed a risk assessment of second generation rodenticides at the 2nd National Invasive Rodent Summit. O'Connor and Eason (2000) discusses the variety of baits which are available for use on offshore islands in New Zealand.

    An investigation Spurr et al. (2007) was carried out to assess the behavioural response of ship rats to four different bait station types. Yellow plastic pipe, wooden box (‘rat motel’), and wooden tunnel bait stations were found all suitable for surveillance of ship rats and the first two at least for Norway rats (all were readily entered and had a similar amount of bait eaten from them).

    Biological: Contraceptive methods of control are currently experimental, but the potential for effective control using contraceptive methods is promising. National Wildlife Research Center (USA) scientists are working on several possible formulations that may make effective oral immunisation possible (Nash and Miller, 2004). français   



         Location Specific Management Information
    Ailsa Craig
    R. norvegicus were eradicated from Ailsa Craig (104 ha) in 1991, after a warfarin poisoning programme led by the Ailsa Craig Working Group (J. Hughes pers. comm, Zonfrillo 2002, B. Zonfrillo, pers. comm.). Monitoring with chew sticks has proven that the island remains rat-free. Seabird breeding success has increased since the eradication, and rare plants, other mammal species and reptiles are reportedly flourishing since the removal of the rats (Williams, 2003).
    Alberta
    Since 1950, Alberta Agriculture has supervised and co-ordinated a rural-based Norway rat control program that has essentially kept the province rat-free. Success is achieved by eliminating invading rats within a control zone 600 km long and 30 km wide along the eastern border of the province. A systematic detection and eradication system is used throughout the zone to keep rat infestations to a minimum. Strong public support and, citizen participation was developed through public education and a sound awareness effort. Although rat infestations within the interior are minor, a rat response plan is in place to deal with a large or difficult case. Government preparedness, legislation, climate, geography, effective rat baits and close co-operation between provincial and municipal governments have contributed to program success (Bourne, 2006). For more detailed information on the control programme, please see Norway Rat Exclusion in Alberta
    Belgium
    The Flemish Region has published a brochure about the control of three species of rodents, the black rat (Rattus rattus), the Norway rat (R. norvegicus) and the musk rat (Ondatra zibethicus). The brochure Ratten in de val, was published by the Water Division of the Ministry of the Flemish Community, in November 2002.
    Black Rocks Is. (Bay of Islands)
    Rattus norvegicus was eradicated from Black Rocks in 1992.
    Bono
    Rattus norvegicus was eradicated from Bono Island (22ha) in 1994, in a programme led by INRA/LPO. The methods used were trapping (30 x 30 m grid, over twelve days) and chlorofacinone (50 ppm, hand broadcast over 18 days). There is one non-target mammalian species on the island (Pascal et al., 1996; Pascal, 1999).
    Breaksea Is. (Breaksea Islands)
    Rattus norvegicus was eradicated from Breaksea Island by the New Zealand Wildlife Service in 1988. Brodifacoum bait stations were used (Veitch and Bell 1990, Taylor and Thomas 1993, Thomas and Taylor 2002). Follow-up monitoring was carried out for two years following the poisoning operation, and confirmed that rats had been eradicated (Thomas and Taylor, 2002).
    Browns Is. (North Island)
    Mice and Norway rats were eradicated from Browns Island in September 1995 by the Department of Conservation. One aerial application of bromadiolone (20ppm) was carried out at a rate of 10kg/ha. In the following weeks mouse and rat traps were set out on a grid. There has been no sign of rats or mice since October 1995. 50 Rentokil bait stations are maintained on the island and checked periodically for rodent sign (Veitch, 2002).
    Campbell Is./Motu Ihupuku (sub-Antarctic) (New Zealand sub-Antarctic Islands)
    Campbell Island is the largest island so far in which an attempt is to be made to eradicate Norway rats using aerial bait drops. In contrast to previous eradications which consist of two bait drops totalling 12kg/ha, Campbell Island will receive a single drop totalling 6kg/ha, but with a 50% overlap to eliminate the risk of gaps. This technique was tested in 1999 over a 600ha field trial carried out on the island. All rats in the baited area ate the bait and would have been killed. Non-target issues are minimal. The drop was to be carried out in July-September 2001, and only one attempt will be made.

    Norway rats were eradicated from Campbell Island following aerial applications of brodifacoum, thirty days apart in 2001(J. Russell, pers. comm.; P. McLelland, pers. comm.). Eradication was confirmed in 2003.

    Canna Is.
    Plans have been developed to eradicate Rattus norvegicus from Canna Island. 3500 warfarin bait stations will be laid along the sheer cliffs of the island.
    Cayman Brac
    Environmental Health Section of the Government maintains a rodent control program (Morgan, 1994 in Varnham, 2006) in populated areas only. The Blue Iguana Recovery Programme carries out additional control to protect hatchling iguanas in the QE II Botanc Park on Grand Cayman (Burton, 2003 in Varnham, 2006). Long-term supression (or eradication) in areas supporting re-established populations of 'Critically Endangered (CR)' endemic Cayman island ground iguana (see Cyclura lewisi in IUCN Red List of Threatened Species) is ongoing (Burton, 2003 in Varnham, 2006).
    Chatellier Is. (Rimains)
    Rattus norvegicus was eradicated from Chatellier Island (1 ha) in 1994, in a programme led by INRA. The methods used were trapping (over twelve days) and hand broadcast of chlorofacinone (50ppm, over 18 days), on a 30 x 30m grid (Pascal, 1999).
    David Rocks (North Island)
    Rattus norvegicus was eradicated from David Rocks A in 1964, in a programme undertaken by the New Zealand Wildlife Service (led by Don Merton). The method used was warfarin (Rid-rat) bait stations over a one year period (Moors, 1985; Thomas and Taylor, 2003; Merton, pers. comm.). The eradication was undertaken to protect the white-faced storm petrel (see Pelagodroma marina in IUCN Red List of Threatened Species) during its breeding season (Thomas and Taylor, 2002).
    Denmark
    Rat control in Denmark is under the control of local municipalities. Since 1907, a special act on rats and their control has been in force. All rat infestations must be reported, and around 100,000 rat notifications are received annually. Property owners are required to ensure that their buildings and premises are rat proof, and that edible food is not available. The total costs of rat control in Denmark is US$7.8 million. Since 1969, some resistance to bromadiolone and difenacoum has been detected. The use of rodenticides in Denmark is now restricted in order to prevent the rapid development of resistance among rat populations. Pest control operators are required to use the weakest rodenticides first.
    East Atoll
    Rattus norvegicus was eradicated from East Atoll (1ha) between 1992 and 1997, in a programme led by D. Taylor (Shaw, 1997; D. Veitch, pers. comm.).
    Enez ar C'hrizienn
    Rattus norvegicus was eradicated from Enez ar C'hrizienn (1.3 ha) in 1996, in a programme undertaken by INRA/SEPNB (led by Michel Pascal). The methods used were trapping over 12 days, on a 30 x 30m grid, and hand broadcast of chlorofacinone (50ppm) over 18 days (Pascal, 1999).
    Falkland Islands (Malvinas) (sub-Antarctic)
    Eradication projects have been carried out on 9 islands in 2001. Some educational work has been carried out and data collected on bird numbers on these islands (Brown et al., 2001a in Varnham, 2006). A guiding document has been produced to assist with prioritising islands for rat eradication (Brown et al., 2001b in Varnham, 2006). Selected control programme are ongoing (Falklands Conservation).Further rat eradications, are planned including eradication from high-priority 305ha North-East Island (Brown et al., 2001a in Varnham, 2006; Brown et al., 2001b in Varnham, 2006). Further selective control is recommended, also eradication from all sensitive sites (mainly islands).
    Fregate Is.
    Initial attempts to eradicate the rats while the population was still small were abandoned when some Seychelles magpie-robins (see Copsychus sechellarum in IUCN Red List of Threatened Species) were poisoned by the rodenticide used. In June of 2000, a second attempt was made. Three aerial applications of brodifacoum (20ppm) were carried out, at a rate of 35 kg/ha, with five and 24 days between the applications. This programme was undertaken by the Seychelles Ministry of Environment (led by Don Merton), and cost US$54,000. Prior to the application of bait, 39 magpie-robins, 330 Seychelles fodys (see Foudia sechellarum in IUCN Red List of Threatened Species), and Aldabran giant tortoises (see Geochelone gigantea in IUCN Red List of Threatened Species) were taken into captivity. Rats were declared eradicated in June 2002. Since then, no mortality has been recorded in recently fledged Seychelles magpie-robins. It is now important to implement strict quarantine procedures, and enhance community awareness, to maintain the rat-free status of Fregate Island. There is a rodent-proof fence in place around the harbour, but this must be maintained in order to remain rodent-proof (Millet, 2001; Thornsen et al. 2000; www.pestoff.co.nz; Merton et al. 2002; Merton, pers. Comm.). (See Hill et al. (2003) and Thorsen et al. (2000) for more details).
    Grand Cayman
    Environmental Health Section of the Government maintains a rodent control program (Morgan, 1994 in Varnham, 2006) in populated areas only. The Blue Iguana Recovery Programme carries out additional control to protect hatchling iguanas in the QE II Botanc Park on Grand Cayman (Burton, 2003 in Varnham, 2006). Long-term supression (or eradication) in areas supporting re-established populations of 'Critically Endangered (CR)' endemic Cayman island ground iguana (see Cyclura lewisi in IUCN Red List of Threatened Species) is ongoing (Burton, 2003 in Varnham, 2006).
    Grass Is. (sub-Antarctic)
    Rattus norvegicus was eradicated from Grass Island (30 ha) in November 2000, in a programme undertaken by the Government of South Georgia and the South Sandwich Islands with support from New Zealand's Department of Conservation. Eradication was confirmed in April 2002.

    In December 2003, the first sighting of the South Georgia pipit (see Anthus antarcticus in IUCN Red List of Threatened Species) was reported. The island is inspected annually to monitor any possible reinvasion by rats from the mainland 350m away.

    Gunner's Quoin Is.
    Rattus norvegicus was eradicated from Gunner's Quoin in 1995, in a programme undertaken by Wildlife Management International Ltd (led by Brian Bell). The eradication was achieved using hand broadcast of brodifacoum (20ppm) and bromadiolone (50ppm) over a one year period (Bell, 2002; A. Khadun, pers. comm.). Although the usual grid size for Norway rat eradications is 100 m, a 25 m grid was used, enabling the rat to gain access to bait more quickly and therefore reducing the overall time of the programme. The bait was lain on the ground rather than placed in bait stations; this is practical only if the weather and soil are dry, and there are no important non-target species. Since eradication, vegetation has responded well, numbers of skinks (Scelotes bojeri and Cryptoblepharus boutonii have appeared to increase, and the night gecko (see Nactus coindemirensis in IUCN Red List of Threatened Species) has been rediscovered. Monitoring has recorded strong seedling growth of Dracaena concinna, Latania loddigesii and Pandanus vandermeerschii (Bell, 2002).
    Handa is.
    Rattus norvegicus was eradicated from Handa Island (363 ha) in 1997 (J. Hughes, pers. comm.; SWT, undated). Since the eradication, puffins have started to recolonise the main island again (SWT, undated).
    Hawea Is.
    Rattus norvegicus was eradicated from Hawea Island in 1986 by the New Zealand Wildlife Service (led by R. Taylor and B.Thomas), using brodifacoum bait stations (Thomas and Taylor, 1989; Taylor, 1992; Thomas and Taylor, 2002; D.Veitch, pers. comm.; J. Russell, pers. comm.). Eradication was achieved in less than two weeks (Thomas and Taylor, 2002).
    Ille aux Chevaux
    Rattus norvegicus was eradicated from Ille aux Chevaux (3 ha) in 2002, in a programme undertaken by INRA, CEL, and SEPNB (led by Michel Pascal). The eradication was achieved using traps on a 30 x 31 m grid over twelve days, and bromadiolone (50ppm) over 18 days (M. Pascal, pers. comm.).
    Ille aux Moines
    Rattus norvegicus was eradicated from Ille aux Moines in 1994, in a programme undertaken by INRA and LPO (led by Michel Pascal). The eradication was achieved by trapping over twelve days on a 30 x 32m grid, and by hand broadcast of chlorofacinone (50ppm) over 18 days (Pascal, 1999; Pascal et al. 1996; M. Pascal, pers. comm.).
    Ille aux Rats
    Rattus norvegicus was eradicated from Ille aux Rats (0.2 ha) in 1994, in a programme undertaken by INRA and LPO (led by M. Pascal). The eradication was achieved using trapping on a 30 x 33m grid over twelve days, and hand broadcast of chlorofacinone (50ppm) over 18 days (Millet, 2001; Thorsen et al. 2000; Pascal, 1999; Pascal et al. 1996; M. Pascal, pers. comm.).
    Intermares
    Eradication of the Norway rat along a 2.3 km section of the nesting area was planned, using anticoagulant brodifacoum, lethal to rats even in small concentrations. Care was taken to reduce risk of poisoning of non-target species. The project has been declared a success as no nests were attacked in the 2005/2006 and 2006/2007 nesting season. Monitoring is ongoing. For more details on the project please follow this link to pages 5 and 6 Zeppelini et al. 2007.
    Kapiti Is.
    Rattus norvegicus was eradicated from Kapiti Island between 1996 and 1998, following an aerial application of brodifacoum (Empson et al. 1989; Empson and Miskelly, 1999; Brown and Sherley, 2002). Offshore stacks were treated by either aerial or hand broadcast of baits, and bait stations were used on three small adjacent islands (Thomas and Taylor, 2002). Weka (see Gallirallus australis in IUCN Red List of Threatened Species ) were adversely affected by the rat poisoning operation, but recovered to pre-eradication levels by 1999, and by 2001 at least four other bird species had increased since the eradication (Miskelly and Robertson, 2002). Non-toxic bait trials revealed that kiore (Rattus exulans) would not use bait stations that Norway rats had used (Cromarty, 2002).
    Karamuramu Is. (North Island)
    Norway rats were eradicated from Karamuramu Island (7.5 ha) in 1999, but reinvaded in 2005 (J. Russell, pers. comm.).
    Kayangel Is.
    A feasibility study was planned for June 2006 as part of a PII (Pacific Invasives Initiative) project, which should lead to a management and eradication plans. Target species for eradication include Norway rats (Rattus norvegicus), ship rats (Rattus rattus), cats (Felis catus) and mice (Mus musculus).
    Langara Is. (Queen Charlotte Islands)
    Rattus norvegicus was eradicated from Langara Island in 1995. The eradication was achieved using brodifacoum (50ppm) bait stations over a two year period (Kaiser et al. 1997). The island was divided into five units. 4000 bait stations were used, and the whole island was poisoned simultaneously. Eradication was essentially achieved in less than four weeks (Thomas and Taylor, 2002). The population of ancient murrelets (see Synthliboramphus antiquus in IUCN Red List of Threatened Species) has since been reported to be increasing (Drever, 2000).
    Little Barrier (Hauturu) Is. (North Island)
    Rattus norvegicus was eradicated from Hauturu Island between 1992 and 1994, in a programme undertaken by the Department of Conservation (led by P. Thomson). The eradication was achieved using bait stations on a 25 x 25m grid over a one year period (P. Thomson, pers. comm.; D. Veitch, pers. comm., J. Russell, pers. comm.).
    In June 2006, Little Barrier Island in the Hauraki Gulf was declared rat free. This follows a two-year pest eradication programme by the Department of Conservation and means endangered species will now have a fighting chance of survival there. It is hoped the same success will also be experienced on the island's of Motutapu and Rangitoto where more than NZD 500,000 has been allocated for similar pest eradication programmes. The New Zealand Department of Conservation's Island Biodiversity Manager, Richard Griffiths, says having no rats on Little Barrier island is already making a big difference, with 90% of Cook's petrel (see Pterodroma cookii in IUCN Red List of Threatened Species) now producing chicks. Griffiths, says tuatara (see Sphenodon punctatus in IUCN Red List of Threatened Species), currently held in cages on the island, will be released into the wild at the end of the year (TVNZ, 2006).
    Little Cayman
    Environmental Health Section of the Government maintains a rodent control program (Morgan, 1994 in Varnham, 2006) in populated areas only. The Blue Iguana Recovery Programme carries out additional control to protect hatchling iguanas in the QE II Botanc Park on Grand Cayman (Burton, 2003 in Varnham, 2006). Long-term supression (or eradication) in areas supporting re-established populations of 'Critically Endangered (CR)' endemic Cayman island ground iguana (see Cyclura lewisi in IUCN Red List of Threatened Species) is ongoing (Burton, 2003 in Varnham, 2006).
    Lucy Is.
    Rattus norvegicus was eradicated from Lucy Island (40 ha) using brodifacoum (Buck, 1995).
    Lundy Is.
    Rattus norvegicus was eradicated from Lundy Island in 2005, in a programme undertaken by the National Trust, RSPB, English Nature and Wildlife Management International Ltd (led by Biz Bell). The eradication was achieved using difenacoum (51ppm) bait stations on a 50 x 51m grid, over a two year period (K. Varnham, pers. comm.). For more information please see Lundy Seabird Recovery Project.
    Malta
    Eradication of rats (Rattus rattus and R. norvegicus) is one of a series of actions being undertaken by the EU LIFE Yelkouan Shearwater Project. The overall aim of the project is to increase breeding pairs from 1500 to 2000 pairs nationally, and from 500 pairs to 700 pairs at Rdum tal-Madonna Special Protected area (75.3 hectares) (BirdLife Malta, undated).
    Maria Is. (North Island)
    Rattus norvegicus was eradicated from Maria Island in 1960, by the New Zealand Wildlife Service (led by Don Merton). The eradication was achieved using warfarin (Rid-rat) bait stations over a two year period, at a cost of US$50 (Moors, 1985; Towns and Broome, 2003; D. Merton, pers. comm.; J. Russell, pers. comm.). The eradication was undertaken to protect the white-faced storm petrel (see Pelagodroma marina in IUCN Red List of Threatened Species) during its breeding season (Thomas and Taylor, 2002).
    Matakohe (Limestone) is.
    Rattus norvegicus has been the subject of ongoing control on Matakohe Island, but constantly reinvades. The island has 800 brodifacoum bait stations on a 25 x 25m grid, 40 box traps, and tracking tunnels to attempt to maintain rat numbers at low levels.
    Mauhaka Rocks
    Rattus norvegicus was eradicated from the Mauhaka Rocks in 1984, in a programme undertaken by the Department of Conservation (led by McFadden and Wilke). The eradication was achieved using two bromadiolone (0.005%) bait stations, over a one year period (Veitch and Bell, 1990; J. Russell, pers. comm.).
    Mayor (Tuhua) Is.
    Rattus norvegicus was eradicated from Mayor Island (Tuhua, 1277 ha) in 2000. The eradication was achieved using an aerial application of brodifacoum (Williams et al. 2002; www.pestoff.co.nz; D. Veitch, pers. comm.).
    Mokoia Is.
    Rattus norvegicus was eradicated from Mokoia Island in 1989, using brodifacoum (Veitch and Bell, 1990; K. Owen, pers. comm.), and the workplan used for the eradication of rats from Breaksea Island (Thomas and Taylor, 2002). It was carried out by the Department of Conservation (led by P. Jansen). Rats were not seen again until 1995, by which time they had recolonised in low numbers (Armstrong, 1999.)
    Motiti Is.
    Rattus norvegicus was eradicated from Motiti Island (1 ha) in 1990, in a programme led by A. Walker. The method used is unknown, but may have involved warfarin (McKenzie, pers. comm.; D. Veitch, pers. comm.).
    Motuhoropapa Is. (North Island)
    Attempts to eradicate Rattus norvegicus from Motuhoropapa Island have been carried out in 1978, 1981, 1984 (New Zealand Wildlife Service, using 1080 and brodifacoum), 1991 (Department of Conservation, using trapping and brodifacoum), 1997, 2001 and 2002 (Department of Conservation, using brodifacoum only). The most recent attempt appears to have been successful so far (J. Russell, pers. comm.; Moors, 1985; Thomas and Taylor, 2002; I. McFadden, pers. comm.; Cameron, 1998; G. Wilson, pers. comm.).
    Motuihe Is. (North Island)
    In 1997 an eradication attempt was made, using two aerial drops of Talon 7-20, containing brodifacoum and bitrex (a bittering agent). There was an eight-day interval between the two drops. A total of 29 birds from ten species were found dead following the poison drop. Trapping for rats and mice in 1999 and 2000 failed to find any rodent sign. A total of 29 birds from ten species were found dead following the poison drop (Veitch, 2002; D. Veitch, pers. comm. in Island Conservation and Ecology Group, 2004).
    Motungara Is.
    Rattus norvegicus was eradicated from Motungara Island (3 ha) between 1996 and 1998, using brodifacoum (Empson and Miskelly, 1999; D. Veitch, pers. comm.).
    Motu-o-kura
    Rattus norvegicus was eradicated from Motu-o-kura (13 ha) between 1990 and 1991 (Adams, 1997; D. Veitch, pers. comm.).
    Moturemu Is.
    Rattus norvegicus was first eradicated from Moturemu Island in 1992, using brodifacoum bait stations (led by I. McFadden of the Department of Conservation) (I. McFadden, pers. comm.; D. Veitch, pers. comm.). Presumably reinvasion occurred as a subsequent eradication was carried out in 2004, this time using trapping as well as brodifacoum, and led by T. Wilson of the Department of Conservation (Russell and Abdelkrim, in prep.; D. Veitch, pers. comm.). Eradication cannot be confirmed until 2006, but DoC Island Biosecurity SOP are in place to prevent reinvasion occurring.
    Moturoa Is.
    Rattus norvegicus was eradicated from Moturoa Island (157 ha) in 1993. Constant reinvasions occur but individuals are trapped or poisoned by various landowners (P. Asquith, pers. comm.; J. Russell, pers. comm.).
    Motutapu Is. (North Island)
    Rattus norvegicus was eradicated from Motutapu Island in 1990 (Brown, 1993).
    Motuterakihi Is.
    Rattus norvegicus was eradicated from Motuterakihi Island (1 ha) in 1985, in a programme led by D. Taylor (Veitch and Bell, 1990; D. Veitch, pers. comm.).
    Ohakana Is.
    An attempt to remove R. norvegicus from Ohakana Island (48 ha) was made in 2006.
    Otata Is. (North Island)
    Rattus norvegicus was eradicated from Otata Island in 1979, 1981 (using 1080, brodifacoum, led by P. Moors of the New Zealand Wildlife Service), 1991 (brodifacoum, I. McFadden, Department of Conservation), 2001 and 2002 (brodifacoum, G. Wilson, Department of Conservation). The most recent eradication remains successful, and tracking tunnels and bait stations are monitored every six months to ensure reinvasion does not occur (Moors, 1985; Veitch and Bell, 1990; I. McFadden, pers. comm.; J. Russell, pers. comm.; G. Wilson, pers. comm.).
    Outer Is. (sub-Antarctic)
    Rattus norvegicus was eradicated from Outer Island in 2001, by Falkland Conservation. The eradication programme used hand broadcast of brodifacoum (20ppm), at a rate of 5kg/ha. Experimental "eradications" were conducted on five other islands (Harpoon, Horse, Rat, Calf Island, and Calf Islet) to test rat re-invasion ability. Please see Report on the Falklands Conservation Rat Eradication Project for details.
    Pakatoa Is. (North Island)
    R. norvegicus was eradicated from Pakatoa Island (29 ha) in 1993, but reinvaded in 1997 (M. Lee, pers. comm.).
    Pakihi Sandspit (North Island)
    R. norvegicus was eradicated from Pakihi (114 ha) in the 1980s, but reinvaded in 1991 (J. McCallum pers. comm.).
    Patiti (Banded)
    Rattus norvegicus was eradicated from Patiti Island in 2004.
    Pearl Is. (Stewart Is.)
    An attempt to remove R. norvegicus from Pearl Island (512 ha) was made in 2005.
    Plate is. (Sept-Ile)
    Rattus norvegicus was eradicated from Plate Island (5 ha) in 1994, in a programme undertaken by INRA and LPO (led by Michel Pascal). The eradication was achieved using hand broadcast of bromadiolone (50ppm) and trapping on a 30 x 36m grid, over a three year period (Pascal, 1999; Pascal et al. 2004).
    Pribilof Islands
    A prevention programme was set up in 1993 to prevent the accidental introduction of rats. This consists of trap and poison stations, community education, outreach to vessels, local shipwreck response capabilities, and regulations. Several rats have been killed on the St Paul docks but there is no evidence of establishment. Snap traps appear to be more effective than poison, but cause minor loss to non-target species.
    Puangiangi Is.
    Rattus norvegicus was eradicated from Puangiangi Island in 1999.
    Puffin is.
    An attempt was made to eradicate Rattus norvegicus from Puffin Island (32 ha) in 1998 (J. Hughes, pers. comm.).
    Rakino Is. (North Island)
    An attempt to eradicate Rattus norvegicus from Rakino Island was made in 1992 by the Auckland Regional Council, but was not successful (I. McFadden, pers. comm.; J.Russell, pers. comm.). A further attempt was made in 2002 by the Rakino Ratepayers Association (led by George Wilson and John McKenzie), using brodifacoum, successfully eradicated Norway rats from Rakino Island. Non-target species included some passerines and scavengers. Residents maintain tracking tunnels and gnaw sticks on the island to prevent reinvasion (J. Russell, pers. comm.).
    Ramsey Is.
    An attempt to eradicate Rattus norvegicus from Ramsey Island (253 ha) was made in 2000 (J. Hughes, pers. comm.).
    Raoul Is. (Kermadec Islands)
    Norway rats are to be eradicated from Raoul Island in the near future, along with cats (Felis catus) and Pacific rats (Rattus exulans).

    Norway rats were eradicated from Raoul Island in 2002 (M. Ambrose, pers. comm.).

    Rasa Is.
    An attempt was made to eradicate Rattus norvegicus from Rasa Island (60 ha) in 1994, in a programme undertaken by Island Conservation and Instituto Nacional de Ecologia (led by Jesus Ramirez). The methods used were brodifacoum (50ppm, wax blocks) bait stations and trapping on a 25 x 25m grid over a one year period (J. Ramirez, pers. comm.; Tershy et al. 2002).
    Rdum tal-Madonna
    Eradication of rats (Rattus rattus and R. norvegicus) is one of a series of actions being undertaken by the EU LIFE Yelkouan Shearwater Project. The overall aim of the project is to increase breeding pairs from 1500 to 2000 pairs nationally, and from 500 pairs to 700 pairs at Rdum tal-Madonna Special Protected area (75.3 hectares) (BirdLife Malta, undated).

    Work on rat control began in December 2006 until March 2007. The aim of the project was to remove rats from the main part of the site and then, using a network of regularly inspected permanent bait stations, detect and destroy any rats moving into the area. Please follow this link Varnham and Meier, 2007 for more details on methods used, results, recommendations and future of the project (Varnham and Meier, 2007).

    Rimains
    Rattus norvegicus was eradicated from Rimains Island (2 ha) in 1994, in a programme undertaken by INRA (led by M. Pascal). The methods used were trapping (over twelve days) and hand broadcast of bromadiolone (50ppm, over 18 days), on a 30 x 38m grid (Pascal, 1999; Pascal et al., 1996).
    Rocher de Cancale
    Rattus norvegicus was eradicated from Rocher de Cancale (0.2 ha) in 1994, in a programme undertaken by INRA (led by M. Pascal). The methods used were trapping (over twelve days) and hand broadcast of bromadiolone (50ppm, over 18 days), on a 30 x 39m grid (Pascal, 1999; Pascal et al., 1996).
    Rotoroa Is. (North Island)
    Rattus norvegicus was eradicated from Rotoroa Island (90 ha) in 1992, but later reinvaded (Lee, 1999; J. Russell, pers. comm.).
    Rotoroa Stack (North Island)
    Rattus norvegicus was eradicated from the Rotoroa Stack (1 ha) in 1992 (Lee, 1999; J. Russell, pers. comm.).
    Rouzic Is.
    Rattus norvegicus was eradicated from Rouzic Island (3.3 ha) in 1951, using hand broadcast of strychnine (50 ppm). The programme was undertaken by LPO and led by Michel Pascal (Pascal, 1999; Lorvelec and Pascal, 2004).
    Saint Helena
    Poisoning campaigns were carried out in the 1990s to control rats in towns (Ashmole and Ashmole, 2000 in Varnham, 2006).
    St Riom Archipelago
    An eradication programme for Rattus norvegicus was carried out on six islets (1.7 ha) of St Riom in 2000, led by CEL, but was not successful. The methods used were trapping and poisoning with bromadiolone. The trap grid was 30m x 30m over a duration of 12 days. The baiting duration was 18 days, using toxin concentrations of 50ppm (M. Pascal, pers. comm.).
    St. Riom
    An eradication programme for Rattus norvegicus was carried out on St Riom (14.5 ha) in 2000, led by CEL, but was not successful. The methods used were trapping and poisoning with bromadiolone. The trap grid was 30m x 30m over a duration of 12 days. The baiting duration was 18 days, using toxin concentrations of 50ppm (M. Pascal, pers. comm.).
    Stewart Is.
    Hickson et al. (1986) describes the use of rat poison at four places near Port Pegasus in southern Stewart Island. These places are visited by fishing boats en route to the Snares Islands, an internationally significant, rodent-free nature reserve in the subantarctic. Controlling rats in remote anchorages is expensive and logistically difficult, so it is important to determine whether or not poisoning significantly reduces the probability of rats boarding boats and how resources should best be deployed.

    Poison was used at remote anchorages of southern Stewart Island in spring and summer of 1984/85 to reduce the likelihood of ship rats (Rattus rattus), Norway rats (R. norvegicus) and kiore (R. exulans) boarding fishing boats heading for the Snares Islands. Poison baits were removed at successively slower rates, probably because poisoning had reduced rat numbers. The effectiveness of poisoning was tested by (i) live-capturing and tracking marked rats at a simulated anchorage near Halfmoon Bay, (ii) poisoning there as in southern Stewart Island, and (Hi) monitoring the survival and responses of the marked population. Population density approximated 2.0-2.5 ship rats per hectare before poisoning. The minimum monthly home range of ship rats averaged 0.54 ha (mean range length 142 m), which is much larger than previously recorded for ship rats in New Zealand. Neither Norway rats nor ship rats were restricted to the shoreline or along creeks. Poisoning caused a 93% reduction in an index of rat numbers in a 0.69 ha poisoning zone over 16 days, and a 76% reduction over the larger 10.4 ha effective trapping area including the poison zone. Poisoning reduces the risk of rats boarding boats, and can protect endangered plants and animals on infested islands (Summary from Hickson et al. 1986).

    SW Crater Rim (Bay of Islands)
    Rattus norvegicus was eradicated from the SW Crater Rim (1 ha) in the Bay of Islands in 1992, in a programme led by D. Taylor (Shaw, 1997; D. Veitch, pers. comm.).
    Takangaroa Is.
    Rattus norvegicus was eradicated from Takangaroa (6 ha) in 1988, in a programme led by T. Clarkson (Taylor, 1989).
    Tarahiki Is. (North Island)
    Rattus norvegicus was eradicated from Tarahiki Island (5 ha) in 2000, in a programme undertaken by the Department of Conservation (led by G. Wilson). The eradication was achieved using brodifacoum (G. Wilson, pers. comm.; D. Veitch, pers. comm.; J. Russell, pers. comm.).
    Taranaki Is. (Bay of Islands)
    Rattus norvegicus was eradicated from Taranaki Island (1 ha) in 1990, in a programme led by D. McKenzie (D. McKenzie, pers. comm.; D. Veitch, pers. comm.).
    Te Haupa/Saddle Island (North Island)
    Rattus norvegicus was eradicated from Te Haupa/Saddle Island in 1989, in a programme led by R. Gilfillan. The eradication was achieved using hand broadcast of brodifacoum and trapping. Traps remained in place following eradication and were checked regularly to ensure no rats remained on the islandn (Veitch and Bell, 1990; Tennyson and Taylor, 1999; J. Russell, pers. comm.).
    Tinui Is. (Rangitoto Group)
    Rattus norvegicus was eradicated from Tinui Island in 1999.
    Titi Is.
    A control programme was initiated in 1970, aiming to reduce rat numbers during the chick fledging period for breeding seabirds, using the warfarin-based Prodide. The rat population was initially reduced, but rats continued to be recorded. Follow-up poisoning was carried out in 1973, but by 1975 rats were still present, and further poisoning was carried out. No follow-up was undertaken until 1981/82, when it appeared that rats were no longer present after six months of continuous trapping. Since the eradication of the Norway rat from Titi Island, there have been reports of increases in the numbers of yellow crowned parakeet (see Cyanoramphus auriceps in IUCN Red List of Threatened Species) and the common gecko (Hoplodactylus maculatus) (Gaze, 2000).
    Tome
    Rattus norvegicus was eradicated from Tome (30 ha) in 2002, in a programme undertaken by CEL and INRA (led by M. Pascal). The eradication was achieved using hand broadcast of bromadiolone (50ppm) over 18 days, and trapping over 12 days on a 30 x 30 m grid (M. Pascal, pers. comm.).
    Trielen
    Rattus norvegicus was eradicated from Trielen Island (17 ha) in 1996, in a programme undertaken by INRA and SEPNB (led by Michel Pascal). The eradication was achieved using traps on a 30 x 30 m grid over twelve days, and hand broadcast of chlorofacinone (50ppm) over 18 days (Pascal, 1999; Kerbiriou et al., 2003; M. Pascal, pers. comm.).
    Ulva Is.
    The use of a 'rolling front' regime to eradicate rats was trialled on Ulva Island in 1992, by the Department of Conservation (led by L. Chatterton) (Island Conservation and Ecology Group, 2004). The island was divided into three blocks which were poisoned sequentially, using Talon WB 50 (brodifacoum) bait distributed in bait stations. Each block received a different loading of poison in order to study optimum baiting levels. However, Talon WB 50 baits had been used for controlling rats on the island over the past decade, and it appeared that some rats were either bait-shy or poison-resistant. The remaining rats were caught by trapping or by using bromadione-impregnated maize (Thomas and Taylor, 2002).

    Rats reinvade Ulva Island on average every two years, and each time they have been removed by intensive trapping (Taylor, 1993; Joyce, pers. comm.; D. Veitch, pers. comm.; J. Russell, pers. comm.; in Island Conservation and Ecology Group, 2004).

    United Kingdom (UK)
    The main management tools for controlling Rattus norvegicus populations in the UK are rodenticide baits. Surveys of farm rat populations have revealed widespread resistance to warfarin, and by inference other first-generation anticoagulants. Reports of resistance to second-generation anticoagulants arose shortly after their introduction in the 1970s.
    Wainui Is. (Bay of Islands)
    Rattus norvegicus was eradicated from Wainui Island (2 ha) in 1991 (D. McKenzie, pers. comm.; D. Veitch, pers. comm.).
    Wenderholm Regional Park
    Intensive control of alien species commenced at Wenderholm in 1992, when annual rodent poisoning began from spring to late summer, alternating between Talon 50 WB pellets (brodifacoum) and Storm Rodenticide (Flocoumafen), to avoid selection for toxin resistance. Initially, drainpipe bait stations were used, but in 1999 these were replaced with Philproof bait stations to reduce bait wastage, and Pestoff Rodent Blocks were used (brodifacoum) as the bait. Rat numbers have been reduced to very low levels, and there is no evidence of predation on translocated robin (see Petroica australis in IUCN Red List of Threatened Species) nests. There is some concern about the residual effects of second-generation anticoagulants, and future poisoning operations may require a more environmentally acceptable toxin.
    West Atoll (Bay of Islands)
    Rattus norvegicus was eradicated from West Atoll (1 ha) between 1992 and 1993 (Shaw, 1997; J. Russell, pers. comm.).
    Whakaterepapanui Is.
    Rattus norvegicus was eradicated from Whakaterepapanui Island (74 ha) in 1999. The eradication was led by Peter Gaze, and used brodifacoum (B. Cash, pers. comm.; J. Russell, pers. comm.).
    Whale (Moutohora) Is.
    Widespread intermittent rat poisoning was undertaken on Whale Island between 1972 and 1977 to reduce rat numbers (Imber et al., 2000). Rattus norvegicus was eradicated from Moutohora/Whale Island between 1985 and 1986, in a programme undertaken by the New Zealand Wildlife Service (led by P. Jansen). The eradication was achieved using an aerial drop of brodifacoum (Jansen, 1993; D. Veitch, pers. comm.; J. Russell, pers. comm.).
    Whale/Tuputupungahau Is.
    Rattus norvegicus has been eradicated from Whale/Tuputupungahau Island (173 ha). The eradication was achieved using brodifacoum, and was led by P. Jansen (Veitch and Bell, 1990; P. Jansen, pers. comm.; J. Russell, pers. comm.).
    Whenuakura Is. (Whangamata)
    Rattus norvegicus was eradicated from Whenuakura Island in 1984, in a programme undertaken by the Department of Conservation (led by McFadden and Wilke). The eradication was achieved using bromadiolone (0.005%) bait stations on a 25 x 25m grid over a one year period (Veitch and Bell, 1990; D. Veitch, pers. comm.; J. Russell, pers. comm.). No rat sign was found in a 2003 survey (Russell, 2003).


         Management Resources/Links

    8. Cunningham, D.M. and Moors, P.J., 1993. Guide To The Identification And Collection Of New Zealand Rodents. Department of Conservation, NZ.
            Summary: A Guide To The Identification And Collection Of New Zealand Rodents, information on trapping methods.
    10. Doty, R. E. 1945. Rat control on Hawaiian sugar cane plantations. Hawaiian Planters Record 49(2): 71–241.
    11. Empson, R. A. and Miskelly, C. M. 1999. The risks, costs and benefits of using brodifacoum to eradicate rats from Kapiti Island, New Zealand. New Zealand Journal of Ecology 23: 241-254.
    12. Hill, M. J.; T. Vel, N. J. Shah., 2003. The morphology, distribution and conservation implications of introduced rats, Rattus spp. in the granitic Seychelles. African Journal of Ecology 41 (2) , 179–186
    13. IUCN/SSC Invasive Species Specialist Group (ISSG)., 2010. A Compilation of Information Sources for Conservation Managers.
            Summary: This compilation of information sources can be sorted on keywords for example: Baits & Lures, Non Target Species, Eradication, Monitoring, Risk Assessment, Weeds, Herbicides etc. This compilation is at present in Excel format, this will be web-enabled as a searchable database shortly. This version of the database has been developed by the IUCN SSC ISSG as part of an Overseas Territories Environmental Programme funded project XOT603 in partnership with the Cayman Islands Government - Department of Environment. The compilation is a work under progress, the ISSG will manage, maintain and enhance the database with current and newly published information, reports, journal articles etc.
    14. Kaiser, G. W., Taylor, R. H., Buck, P. D., Elliott, J. E., Howald, G. R. and Drever, M. C. (1997) The Langara Island Seabird Habitat Recovery Project: Eradication of Norway Rats – 1993–1997. Technical Report Series No. 304, Canadian Wildlife Service, Pacific and Yukon Region, British Columbia.
    20. Moors, P. J., Atkinson, I. A. E. and Sherley, G. H. 1992. Reducing the rat threat to island birds. Bird Conservation International 2: 93–114.
    33. Taylor R. H. & Thomas B. W. 1989. Eradication of Norway rats (Rattus norvegicus) from Hawea island, Fjordland, using brodifaceum. New Zealand Journal of Ecology 12: 23 - 32.
    34. Taylor R. H., Kaiser G. W. & Drever M. C. 2000. Eradication of Norway rats for recovery of seabird habitat on Langara Island, British Columbia. Restoration Ecology 8: 151 - 160.
    38. Thorsen, M.; R. Shorten, R. Lucking and V. Lucking., 2000. Norway rats (Rattus norvegicus) on Frégate Island, Seychelles: the invasion; subsequent eradication attempts and implications for the island's fauna. Biological Conservation Volume 96, Issue 2, December 2000, Pages 133-138
    39. Tompkins J. 2001. Eradication of Rattus norvegicus from Seabird habitat in Canada. CWS, British Columbia, Canada.

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