Rat control programme for Le Roys Bush community

Pest Management Programme for homes and other property adjoining Le Roys Bush – 2016 Rat Blitz

Details of rat programme

Goal

The goal of this programme is to reduce pest animal numbers to 12-15% in the Reserves by controlling populations in the surrounding private bush in 2015-2017

The main focus for 2016 is to continue with and improve the rat control blitz programme. Neighbours can also borrow possum traps (Timms Traps or Trapinator) or a stoat trap from Beyond the Fence or Le Roys Bush Management Committee. No stoat control is planned at this point. Groups can also get help for weed management under the Beyond the Fence programme.

Background

Since 2011 rats have been controlled in Le Roys Bush (LRB) and surrounding private property. 124 rat bait stations were mapped out by Te Ngahere, both within and surrounding the Reserves, and were actively managed by volunteers. The bait used was second generation Bromadialone (“Contrac” / “TomCat”), and the stations (Protector Sidekick) were supplied by Auckland Council.

In the second half of 2014, NZ Biosecurity Services was employed by Auckland Council – Parks to manage the pest animals on the Reserve (public) land. NZ Biosecurity Services met with the LRB volunteers and some Auckland Council staff and explained they would be using Pindone bait, in 13 Pied Piper stations located from Highbury to Little Shoal Bay.

Even though the Reserves are now being actively managed, the surrounding bush on private land actually has a more active rat population. It continues to need active pest animal control, and the local volunteers are keen to ensure this happens.

Participation

There are approximately 160-180 households bordering the Reserves. Ideally 80% of the neighbours (approx 130-145 people) would be involved in the rat management programme.

Participants will be offered:

· Free bait (through Auckland Council)

· Bait stations “Protecta Sidekicks” or “TomCats” (participants bordering Reserve will be lent a station to use, others can buy their own station at cost $19) or traps if they enquire/prefer.

Each station/trap to include a sticker with a warning and contact details for local people. Bait stations will be numbered where possible.

· Free gloves and marker tape are available

· Best practice advice and support – effective baits, best stations, Rat Blitz baiting programme – as they are part of the programme.

Baiting Programme

Two types of bait (one first generation, one second generation) will be used, in four “rat blitzes” per year. That is, volunteers will fill and monitor their bait stations for a couple of weeks, four times a year only. This approach known as “pulsing” the bait reduces bait shyness, reduces wastage and the amount of toxin in the area.

The first two rat blitzes (May/June and September – either side of winter) will be done with brodifacoum (Pestoff) or a similar second generation bait, then the second two rat blitzes (end November / beginning December, and February) will use diphacinone (RatAbate). By switching between the two, we maximise effectiveness and minimise potential build-up of brodifacoum in the area.

During a rat blitz, please check stations every 1-2 days for diphacinone (RatAbate) or every four days for brodifacoum (Pestoff) and keep bait levels topped up (this is very important for the diphacinone (RatAbate) rat blitzes - don’t let the station go empty as the bait needs to be consumed multiple times on successive nights). If little/no bait is taken during the first rat blitz, try reducing the amount of bait being used in subsequent rat blitzes to avoid wastage.

For those who don’t want to use bait, rat traps can be used in a similar way. Put traps out at the same time as the bait rat blitzes (four times a year) and check every two days. Traps can be set inside ice-cream containers with a rat sized hole cut into it, which is a cheap option to help exclude larger animals/non-target touching the trap. Alternatively, tracking tunnels can be used (with one end blocked off so they only have one way in if it is a one direction trap).

Participants should know that “we don’t get rats down with traps alone” (advice from Auckland Council biosecurity) – on Motutapu Island recently, a rat was found on the island and despite best attempts it wouldn’t go near a trap – toxins had to be used to eliminate it.

Best practice baiting

Use gloves to both protect your own health and to prevent human scent transferring to the bait and station.

Check bait every 1-2 days for diphacinone (RatAbate) or every four days for brodifacoum (Pestoff) and keep stations topped up as required as outlined above. If little/no bait has been taken after three weeks, remove the bait.

Only fresh bait should be used, do not re-use old bait. Old bait can be wrapped carefully and placed in the rubbish to be sent to landfill.

The best idea is to reduce the amount of bait put out to reduce wastage (e.g. if four blocks are put out and not taken, reduce it to two).

Bait station placement

Stations should be distributed approximately 50m - 75m apart. This will mean that an average 600-700sqm property will have 1-2 stations depending on bush cover and type (e.g. more fruiting trees like puriri = more rats = more stations required).

Attach stations to the dry side of trees/posts with the opening 25-30cm above the ground. This optimises their use by rats and avoids rain water splashing off the ground affecting bait quality. Stations should be at least 50m from any waterways.

Ensure that any station is easily accessed. Hard to access stations are less likely to be checked frequently.

More information about the bait

Brodifacoum (Pestoff)

· Second generation anticoagulant bait for rats but will also kill possums.

· Second generation baits are stronger so more effective, but they are also more persistent in food webs,

· Low water solubility but still eco-toxic, no raw product should be entering a water system.

· Pros: Proven successful in many eradication campaigns. Its well-known effects means there is a clearer idea of the mitigation actions necessary to minimize non-target risks. An antidote is available (for pets and humans). Slow acting allowing secondary poisoning of cats.

· Cons: Significant non-target risks to wildlife and pets. Can remain in liver of sub lethally poisoned animal for months which can cause secondary poisoning for animals further up the food chain (e.g. harriers and morepork).

Diphacinone (RatAbate)

· First generation anticoagulant bait designed to be highly palatable for rats.

· The active ingredient is diphacinone and is significantly less persistent than other rat poisons (98.4% less persistent than brodifacoum). Has little or no secondary poisoning effects.

· Eco-toxic, no raw product should be entering a water system.

· Pros: Diphacinone has successfully eradicated ship rats on some small islands. It’s also readily metabolized.

· Cons: Generally require rodents to feed on them multiple times on successive nights to be effective. Significant non-target risks to wildlife and pets.

Monitoring

Tracking tunnels and the like are rendered ineffective as monitoring tools unless hundreds are used (as the same animal can walk through multiple times), however they are useful to show presence/absence and for educational purposes. This programme will undertake basic, effective monitoring to determine if the programme is working and desired results are being achieved:;

· Bait take – neighbourhood co-ordinators to collect bait take information at the end of each rat blitz and send through to LRB

· Photos of bush (each participant to take a photo of their general bush area before the programme commences and send to leroysbush@gmail.com)

· If a local school or similar group gets involved, we may do some tracking (e.g. invertebrates) or use wax tags or chew cards for educational purposes.

Chew cards are available from http://www.connovation.co.nz/pest-monitoring

Pest plants and other bush care

The Beyond the Fence project also aims to help local groups of people to control pest plants in and around Le Roys Bush and to prevent damage to the bush.
For more information about this, please go to beyondthefence.org.nz or leroysbush.org.nz
To get regular news from Le Roys Bush and Beyond the Fence, please join Le Roys Bush on Facebook and/or subscribe by email to leroysbush@gmail.com

Kauri die-back

- Before working near kauri trees, please wash/scrub your boots thoroughly to remove all dirt that may have come from other sites.
- We can supply Trigene if you wish.

Health and Safety – volunteers to agree to this before receiving a bait station

All volunteers for the LRB Pest Animal Management Programme must be aware of the hazards detailed below and sign their agreement to follow the hazard minimisation advice given.