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Pest mammals in

Hamilton city

Dai Morgan

Email: dai1@waikato.ac.nz

Phone: 8384466 extn 8123

Introduction

• Introduced mammalian pests are bad news

• Comparatively little research on urban predators

• Limited knowledge on which pests are in Hamilton

– Practically nothing known on their distributions

Videoed predators in podocarp-broadleaved

forest

REF harrier ship

rat

possum stoat more-

pork

Flux Mapara kokako 2 8 3 2 0

Innes Rotoehu kokako 5 1 4 0 0

Innes Motatau kereru 0 1 3 0 0

James W’holm kereru 0 0 1 0 0

Flux T/riro fantail 0 2 0 0 0

P’land W’naki kaka 0 0 1 0 0

Brown Kaharoa tomtit 0 7 0 0 0

Brown Kaharoa robin 0 3 0 0 2

TOTAL 7 22 12 2 2

Videoed predators in rural areas (Waikato)

magpie

Predator

ship rat harrier cat

pukeko

blackbird

thrush

goldfinch

greenfinch

mallard

TOTAL

1

1

1

5

1

7

3

3

1

1

8

3

2

5

1

1

total nests monitored= 38

no. fledged= 9 (24%)

Videoed predators in Hamilton City

• 21 nests monitored (mostly in residential gardens)

• Blackbird, song thrush, fantail, silvereye nests

• 10 nests successful (48%)

• 5 predation events filmed

species stage when

event occurred

predator

blackbird

blackbird

song thrush

fantail

fantail

chicks

chicks

eggs

chicks

eggs

cat

cat

ship rat

ship rat

ship rat

Pest mammal

inventory

Hamilton city

• Six gullies

• Six parks

• Six residential

areas

• Two of each

habitat types

surveyed per

week

• Survey

conducted in

March-April 2007

Survey methods

Device / method Target species

Tracking tunnel

WaxTag

Live catch traps

Scat/ animal sign survey

Public survey

rodents, hedgehog, mustelids

possum, rat

ship rat, Norway rat

rabbit, possum, cat, hedgehog

mainly cat

Tracking tunnel results

• NO MUSTELIDS DETECTED

Mean % of tunnels tracked by pests in each habitat

* = the number of areas per habitat that each species was detected

Species

Gullies

Parks

Residential

rat

hedgehog

mouse

15% (5/6)*

22% (5/6)*

30% (4/6)*

5% (2/6)*

25% (6/6)*

14% (3/6)*

0%

12% (3/6)*

0%

WaxTag results

Species

Gullies

Parks

Residential

possum

rat

19% (5/6)*

5% (3/6)*

0%

2% (1/6)*

0%

0%

* = the number of areas per habitat

that each species was detected

Footprint images courtesy of kiwifoundation.org.nz

rat possum

Ship rat vs. Norway rat

• Different behaviours

– Ship rats more

important predators

Hamilton survey

• 404 trap nights

• 2 Norway rats

• 19 ship rats Norway

Ship

Ship Norway

Ship

Norway

Monitoring pest mammals

• DOC established rodent and mustelid

protocols

• For gullies, presence/absence probably

most appropriate

• NPCA established possum protocols

• For gullies, presence/absence probably

most appropriate

Kill traps

WHY DO YOU WANT TO REDUCE MAMMALIAN

PESTS?

- need to determine what you want to achieve

Many types of traps; e.g.,

- Multi traps- mustelids and also rodents

- Snap traps for rodents

- Timms and Sentinel traps for possums (WRC

have Timms traps for borrowing)

• Comply with Wildlife Act

• Minimise non-target catch

Live capture traps

Good because of low non-

target species issues

Bad because you have to deal

with a live animal

Conclusions

• Most pests in Hamilton live in Gully habitat, and are

dominated by ship rat and possums (and cats)

• Identify predators in you gully before and after control

– Some easy and relatively cheap methods

• Establish why you want to control pest species in your

gully

• Determine an appropriate course of action and ask for

help if you need it!

Some useful contacts

Connovation (www.connovation.co.nz) – Tracking tunnels, possum

traps

Pest Control Research (www.pestcontrolresearch.co.nz) – Baits,

WaxTags, multi-traps and other traps (just about everything). Also,

bite-mark identification sheets etc

Pest Management Services (www.nopests.co.nz) – Live traps

Phil Proof (www.philproof.co.nz) – Baits, traps, stations, tracking

tunnels

NZ Kiwi Foundation (www.kiwifoundation.org.nz) – monitoring protocols

and footprint identification

Waikato Regional Council- advice and Timms traps