An exciting project enhancing the kiwi population at Lake Rotoiti

 Photo- Tracey Grose

Photo- Tracey Grose

The future of great spotted kiwi (GSK) at Lake Rotoiti has been greatly enhanced by the launching of a Friends of Rotoiti (FOR) project. Kiwi calls are only occasionally heard  in the Park and we hope to increase this unique experience.

FOR has been granted $55,000 from the Department of Conservation (DOC) Community Fund towards a 3 year project, in partnership with DOC, to enhance the existing GSK population.

16 GSK scourced from the Goulan Downs in Kahurangi National Park were introduced by DOC to the Mainland Island via 2 translocations in 2004 and 2006. Breeding activity was not as high as expected so 13 additional birds from Operation Nest Egg (ONE) have been added over the last 5 years with limited success.

Currently there are about 30 GSK in the Mainland Island and the project aims to increase the genetic biodiversity making the founder population more sustainable. It has been determined that at least 40 individuals are necessary for a viable founding population. This genetic diversity increase will be achieved by locating, capturing and introducing a further 20 birds.

FOR has been working in partnership with DOC for 16 years and has developed an excellent working relationship however we will need increased public support over the next 3 years to assist with this intensive work.

The initial stage of the project involves the training of FOR members in all aspects of kiwi location, capture, translocation and management. We are working towards developing a dedicated “hands on” group of kiwi enthusiasts to make this project successful. Persons wishing to join and/or support this group can contact FOR through the website www.friendsofrotoiti.co.nz.

“What New Zealand conservationists have done is to demonstrate that you have to be active, you have to be imaginative, decisive – you have to do something”.

Sir David Attenborough

Rotoiti Nature Recovery Project opening, Lake Rotoiti, February 1997

 

Great spotted kiwi acoustic monitoring

 

Context:

Great spotted kiwi (GSK) were first introduced to the Rotoiti Nature Recovery Project (RNRP) in 2004. Intensive monitoring of these translocated kiwi occurred over the next ten years with territories mapped and breeding success monitored. Monitoring of kiwi within the RNRP has shown that productivity is low, about 1 chick per year, and that adult mortality is low. As a result, we expect the population to be growing very slowly. To supplement this population and to increase the number of founder adult kiwi to the required 40 individuals, twenty adult GSK will be translocated into the RNRP over the next three years. Prior to these translocations it is necessary to establish where GSK territories currently are within the RNRP so these can be monitored for change with the introduction of new kiwi. It is also important to begin long term monitoring to monitor the population trend of GSK within the RNRP. Both of these activities will be undertaken using acoustic recorders due to the low call rate of GSK in the RNRP. Acoustic recorders will be deployed in March 2018 to determine current GSK territories and then in March 2019 and 2020 to determine how territories change. Following the completion of translocations recorders will be deployed annually in March to monitor long term changes in the GSK population. GSK peak calling is between November and March. While peak period of calling during the night is often the two hours before dawn for GSK it is unknown whether this is the case for GSK within the RNRP. As most GSK call rate monitoring occurs in the four hours after dusk, rather than before dawn, the RNRP will also carry out its monitoring during this time.

 

 

Purpose:

1.     Establish locations of existing GSK territories within the RNRP prior to translocation of new adult kiwi into the population.

2.     Determine how territories and distribution changes with introduction of new adults.

3.     Carry out long-term population trend monitoring using acoustic recorders annually.

Method:

For long-term monitoring, the recorders must be deployed at exactly the same location (site and position on a tree or post) in the same month of the year, and at the same start and finish time each time. Monitoring should be carried out in the period a week either side of the new moon as the relationship between calling rate and phase of the moon is complex and varies between species, and possibly between habitats and situations. This standardisation reduces the number of variables, making it easier to detect any real differences in call rate. Monitoring will be carried out before the translocation (March 2018) and then once translocations have been completed at annually in March.

 

 

 

Fifteen recorders will be deployed within and around the RNRP in March for 15 nights. Recorders will be deployed one week before the new moon, and retrieved a week after the new moon. FOR volunteers will deploy as many recorders as possible. Depending on how many volunteers are available and ability DOC staff will likely have to deploy recorders also. Recorder sites will be GPS marked, a yellow labelled triangle put up on the closest tree, two pieces of orange flagging attached to the branch where the recorder was hung and a photo taken. This will ensure recorders are placed in the exact location each year.

 

In 2018 recorders monitoring will run from the 10th of March to the 25th of March. Recorders can be put out before and collected after these dates but only nights from 10-25th will be included in monitoring. In 2018 from the 15 nights of recordings the 13, 15,22,23 and 24th will be the five nights excluded due to high disturbance.

 

Recorder Set Up

1.     Programme all the recorders the day prior to monitoring with following:

a.     Check time and date are all correct

b.     Programme 1 recording session to start at 2030 and finish at 0030 on the low setting

c.     Check SD card

 

Fieldwork

1.     Remove paper tabs from batteries on the morning of the operation before issuing so that recorders are activated before leaving the office.

2.     Navigate to each pre-marked location point by GPS, at the site is a yellow triangle attached to a tree with the site ID and then two pieces of tape hanging from a branch. Attach the recorder to the branch where the tape is attached.

3.     Record the recorder ID for each site.

4.     When retrieving recorders remove from branch and check that yellow triangle is still present and that tape on branch is in correct location. Record the recorder id from each site.

5.     When back at the office return recorders to the designated downloader.

6.     Downloader is to download all recordings on the day of collection and store on the RNRP harddrive and backed up onto the FOR harddrive.

 

Analysis Management

1.     Before data is analysed the 15 nights of recordings will be quickly scanned by a staff member and the 5 nights with the greatest noise interference, based on the colour of the background noise will be set aside.

2.     Data will be analysed by volunteers both on site and at home.

3.     Volunteers will be issued with recordings to analyse via USBs storage devises from the RNRP harddrives, and then analysed on Audacity.

4.     Data will be recorded by volunteers onto excel spreadsheets that will then need to be collated. Hard copies will be stored in the bio office.

 

Analysis of recordings

1.     Each site will have a folder containing subfolders of nightly recordings. Within sub-folders recordings are stored in 15 minute blocks.

2.     Go through each 15-minute recording and for each record:

a.     The number of male and female calls, and their strength on a 1–3 scale (1 being strong with a very clear outline, 3 being very faint).

b.     The number of duets (where a bird responds within 10 seconds (but usually much less) after the end of a call sequence by a bird of the opposite sex).

c.     In cases where a call is interrupted mid-sequence (as often occurs during great spotted kiwi duets), record it as one call if the bird resumes calling mid-sequence and two calls if the birds restart their call from the beginning.

d.     Record background noises on a 0–3 scale (wind = calm to strong; rain = none to heavy; and other (e.g. sea, rivers, insects, other animals, aircraft) = no interference to very noisy). Note that although some of these other noises would ordinarily affect human listening, the kiwi calls will likely still be clearly visible on the spectrogram because their frequency ranges are often very different.

3.     Only record complete 15-minute recording periods. If a count is halted part-way through a 15-minute block (e.g. if heavy rain starts and obliterates any chance of seeing kiwi calls), that complete block should be set aside. Record why the period could not be analysed.

4.     Make notes about any recordings that you would like double checked.