Wildlife Monitoring

Monitoring is carried out to assess the effects of pest control on the native wildlife species we want to protect. Annual kiwi listening is carried out at night to assess kiwi populations and bird counts are carried out during daytime to assess other bird species. The Trust commenced monitoring of invertebrates during 2008. Volunteers are wanted to help with all aspects of monitoring.

Kiwi Monitoring

North Island Brown KiwiKiwi call monitoring is carried out annually by volunteers and Department of Conservation staff sitting out at established listening points scattered throughout the Trustís management area in Puketi Forest. Listening is undertaken in May and June, when kiwi calling is at its peak. Calls are recorded during the first two hours of darkness on at least two nights, preferably fine calm nights without a moon. By recording the time, direction, estimated distance and sex of each call, the number of kiwi calling within the area can be measured. Although not all birds call, a useful index of the kiwi population is obtained.

Juvenile kiwi donít start calling until they are 3 or more years old, so the effects of predator control on breeding success are not immediately obvious.

Monitoring was first carried out in 2000, with further listening in 2004, and 2006 to 2009. Because of their distance, it is necessary to camp out at the more remote sites, and the Trust is grateful to members of Far North Search and Rescue for monitoring these two sites.

A summary of the numbers of kiwi heard calling from 2000 to 2009 is shown in the table below. There was a decline in call numbers from 2000 to 2004, which might reflect the effect of predation before the start of pest control. From 2004 to 2006 the number of female kiwi calling increased by about 70% and males calling increased by 24%. Numbers remained similar in 2007 and 2008, and there is a suggestion of further increase in 2009. The results are hopeful, but must be interpreted cautiously because several uncontrolled variables affect call rates.

Kiwi Listening Results 2000 - 2009:

SiteMean calls per hour
Pond - Bramley's Ridge-
Totara Ridge-3.755.75-0.757.1
Bramley's Ridge
(near end)
Pirau Road (central)1.000-01.0
Takapau/ Pirau Road-
Raingauge Pirau Road3.03.752.
Walnut/ Pirau Road-0.334.
Pudding Bowl Hill-
Kokako Track1.250.753.
Waihoanga/ Takapau junction6.01.752.0-3.755.4
Forest Pools4.50----

SiteTotal birds calling (female)
Pond - Bramley's Ridge-4(1)8(3)4(1)5(1)6(2)
Totara Ridge-7(2)7(3)-2(1)8(4)
Bramley's Ridge
(near end)
Pirau Road (central)2.5(1)00-02(0)
Takapau/ Pirau Road-21115(2)
Raingauge Pirau Road9(2)5(1)44(2)6(1)7(3)
Walnut/ Pirau Road-15(1)8(4)3(1)8(3)
Pudding Bowl Hill-24(1)3(1)06(3)
Kokako Track43(1)3(2)45(2)4(2)
Waihoanga/ Takapau junction10(2)2(1)3(1)-4(1)6(3)
Forest Pools5(1)0----

Bird Counts

New Zealand fantailThe presence of birds active in the forest during daytime is monitored by experienced birdwatcher/ornithologist volunteers during spring and autumn. At the same points in the forest each time, the total number and species of birds seen or heard in 5 minutes are recorded.

The effects of rat removal are shown dramatically in a comparison between April 2005 and April 2006, before and after the first season of rat control. The total number of birds recorded from the eight bird count locations within the core area of rat control increased from 53 in 2005 to 98 in 2006 - an increase of 85%. By contrast, at seven bird count locations outside the rat control area there was an increase of only 8% in bird numbers. This reinforces the devastating impact that rats have on the smaller bird species.

Total Birds Seen and Heard: 16 April 2005 and 20 April 2006:

bird count table

Invertebrate Monitoring

Invertebrate monitoring began in May 2008, with pitfall traps used to compare populations of ground dwelling invertebrates in the areas of pest control.

A pitfall trap is a plastic container, approximately 10 cm diameter by 10 cm deep, set in the ground with its rim flush with the ground surface. A small amount of ethylene glycol is placed in the base of the container and a raised cover is provided to keep rain out. Wandering insects and other small invertebrates that fall into the container are preserved by the ethylene glycol. After one month, the containers are retrieved and the contents sorted, identified and counted.

For this monitoring, two lines of 10 traps at 10 metre spacing were set out, one in the core area receiving control of rats, stoats, possums and cats, and one outside the core area receiving stoat and cat control only. The pitfall traps from the first monitoring period have been retrieved and results will be available when sorting and identification is complete.

This page last updated: 11 August 2009

© 2006-2009 Puketi Forest Trust