MEMO

To: Andy Hicks From: Keiko Hashiba Date: 5 November 2018 RESULTS OF CRYPTIC SURVEY AT WHAKAKI, RAHUI Subject: CHANNEL, TE PAEROA, AND WAIRAU File Ref: Bernie Kelly, Hand Rook, Helen Jonas, Malcolm Smith, Matt Brady, Cc: Nicolas Caviale-Delzescaux, Rod Dickson

BACKGROUND

Since 2017 HBRC’s Hot Spot Funding has been allocated to the Whakaki Lake and surrounding areas to make further progress on addressing water quality issues.

While the overall goal is to improve the water quality of the Whakaki Lake, more holistic approach is taken to address wider biodiversity issues. Actions include habitat improvements for wildlife who utilises a series of wetlands within the catchment.

The bird survey targeting wetland obligate were requested by the HBRC and Whakaki Lake Trust in order to help gauge the success of a variety of restoration initiatives in the area.

PURPOSE OF THE SURVEY AND THE REPORT

Purpose of the survey was to collect baseline information on spotless crake and fernbird. These species are recognised as indicator species for overall wetland conditions, such as the wetlands habitat provision function, level of predation, and health of other flora and fauna (e.g. fish and insects that depend upon).

Australasian bittern is qualitatively surveyed alongside with fernbird and spotless crake due to its highest threat status granted by the Department of Conservation, and also our region is one of the strongholds of this species. Total national population of this species is estimated to be 750 – 1000, and Hawke’s Bay supports 10 – 15% of the national population. Therefore any information on this species will contribute to its conservation effort nationally.

Note that the DOC coordinated the evening survey of bittern booming on the nights of 23rd and 24th October 2018. Results from this evening surveys will be reported by the DOC. The bittern results shown in this report is from the day-time incidental observations as described above and also in the method.

We noted many existing values in regards to the habitats. However the current report does not cover the characterisation of these wetlands.

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SURVEY AREA

Survey area includes Whakaki, ephemeral wetland between Whakaki and Te Paeroa (“Ephemeral (2N)”, Rahui Channel, Te Paeroa and Wairau.

SURVEY METHOD

Survey was carried out on the mornings of 24th (Whakai) and 25th (Rahui Channel, Whakaki - Ephemeral “2N”, Te Paeroa and Wairau) October 2018. Survey team consisted of below (alphabetical order);

 Bernie Kelly  Hans Rook  Helen Jonas  Keiko Hashiba  Malcolm Smith  Matt Brady  Nicolas Caviale-Delzescaux  Rod Dickson

We formed four 2-person teams to survey.

The survey method developed by the Department of Conservation (O’Donnell, n.d.) (see Appendix 1 for details) was followed. Key procedures was as follows;

1. We commenced the survey at 6 am (recommended timeframe is 6 am to 10 am). 2. At each count station, 5 minute play-back of a pre-recorded calls (interspersed by pauses) supplied by DOC was used to detect spotless crake. All birds either heard (Hd) or observed (Ob) were recorded in the survey form. If fernbirds were heard or seen during this initial 5 minutes, birds were recorded in the sheet. 3. After the initial 5 minutes, passive listening for fernbirds were carried out for 5 minutes. All birds either heard (Hd) or observed (Ob) were recorded in the survey form. If observer deemed the bird to be the same bird as recorded in the previous 5 minutes, they were not recorded (this is to avoid double counting). If spotless crake were heard or seen during this second 5-minute period, they were recorded in the sheet.

Australasian bittern was recorded when heard or observed throughout the survey. The purpose was to capture the presence/absence, rather than counting to understand the population1.

Number of count stations are shown in Table 1. Each count station is located at 200 m apart (Figure 1). Count stations at Whakaki was established by DOC in 2011, where we conducted the current survey except stations 3 – 9 and the 300 series. For the 3 – 9, surveyors have set up the points closest to the original locations due to the fact that the team had to use GPS which didn’t have the original way points pre-loaded. For the 300 series, surveyors move many of the way points closer to the water’s edge as the original points were mostly on dryland (because originally were set up for fernbird survey), and would unlikely to support any spotless crakes in the future.

The rest of the count stations were newly established for this survey.

1 As mentioned above, the same survey team plus a few local volunteers helped DOC to conduct evening survey of bittern booming listening on the nights of 23rd and 24th October but this results are not covered in this report and will reported separately by DOC.

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Table 1. Number of count stations surveyed in October 2018.

Wetland Name # of count stations

Whakaki 33

Rahui Channel 10

Whakaki ‐ ephemeral (2N) 9

Te Paeroa 15

Wairau 9

Grand Total 76

Survey was concluded between 9 am to 11:30am each day (each team covered varying number of count stations and terrains).

RESULTS

Most of the birds were recorded at Whakaki. There were very few records at the rest of the wetlands surveyed.

Total of 4 spotless crake were heard at 3 count stations at Whakaki (Figure 2). One was heard between count stations 902 and 903 at Wairau. No spotless crake was recorded at Rahui Channel, Te Paeroa, and Whakaki – ephemeral (2N).

24 fernbirds were recorded at 13 count stations (Figure 3), all of which were at Whakaki.

Bitterns were recorded at a few count stations around Whakaki, and also at one count station at Wairau (Figure 4). Three different birds were observed (i.e. visually seen) by surveyors at 3 locations. Other booming birds were also recorded simultaneously at these locations. This indicates that there could be 7 birds recorded by surveyors during the survey. However this is only an indicative figure and location. , and accurate understanding of the population size.

DISCUSSION

Most of the cryptic species were recorded from the Whakaki. This may be reflecting the habitat structure suited to these species.

Spotless crake require habitat consisting of shallow open water with reeds, rushes and sedges. Fernbird favours habitats where thick and bushy low-line (e.g. sedges, raupo, flaxes) vegetation with some high vegetation (e.g. manuka, kanuka).

Lack of records of fernbird and spotless crake from Te Paeroa, Wairau, Ephemeral (2N) and Rahui Channel may be explained by the lack of habitats suited to/favoured by fernbirds and spotless crake. It may also be due to the presence of predators in these wetlands which are relatively smaller in habitat sizes compared to the main Whakaki Lake. For example, some

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PAGE 4 OF 14 sign of predators along the Rahui Channel (presumably feral cats) were noted, which may explain the absence of these birds from these wetlands.

RECOMMENDATIONS

Below are some recommendations which may make a big difference to the wildlife as well as help improve the water quality of the lakes and wetlands:

 Enhancement planting with species that are native (or should be native) to the area. Particularly Cyperus ustulatus (giant umbrella sedge)  Enhance the recovery of existing sedgeland (Bolboschoenus sp., Carex geminata, Cyperus ustulatus), rushland (Juncus krausii) and reedland (). This could be achieved by a range of actions including but not limited to; a) stop grazing, b) improve hydrological connectivity (e.g. wetlands along the Rahui Channel could be connected with the main channel), c) control weeds such as Pampas grass.

Predator control targeting feral cats and mustelids where it hasn’t been put in place will likely to support the wildlife and improve their survival. Rodent control is preferable for protection of eggs and chicks. Rodent control will also improve other wildlife such as lizards.

It is also recommended to carry out detained vegetation mapping of these wetlands using drone. Vegetation may be changed depending on the hydrology and opening of the mouth, which will then affect the distribution and number of these cryptic birds. Therefore it is critical to monitor the vegetation pattern going forward.

ACKNOWLEDGEMENT

Special thanks to Bernie Kelly and Hans Rook who provided invaluable help to this survey and gave the rest of us the depth of knowledge of these birds and wetlands.

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Figure 1. Location of bird count stations.

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1 heard between 902 & 903

Figure 2. Result of spotless crake. All records are ‘heard’. One bird was heard at Wairau between count stations 902 and 903.

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Figure 3. Result of fernbird count. Birds were either heard or observed.

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Presumably 2 bitterns (1 booming, 1 observed)

Presumably 2 bitterns (1 booming, 1 observed) Presumably 1 bittern

Presumably 2 bitterns (1 booming, 1 observed)

Figure 4. Result of incidental bittern observation. Birds were either heard or observed. Indicative number of birds and their approximate locations recorded during the survey are shown. 3 bitterns were observed at 200’s, 300’s and #8 while there were other birds booming. Multiple bitterns were recorded at Wairau in the past by the landowner, however one was heard recorded booming on the survey day.

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APPENDIX 1

Standardised call‐playback protocol for monitoring FERNBIRD at Whangamarino wetland

1. OBJECTIVE A. To estimate population trends in fernbird using indices of relative abundance in areas with and without predator trapping at Whangamarino wetland. B. To establish a baseline index against which to monitor future trends.

2. COUNT PROTOCOLS a. Five‐year performance measure: No significant declines in indices of fernbird abundance after 5‐ yearsof continuous trapping. b. Count type: Passive listening at point stations. c. Count length: 5 minutes per count. d. Sample size: 100 counts per sampling session (50 in treatment area, 50 in non‐ treatment). e. Distance between stations: 200 m. f. Frequency: Annual. g. Location of stations: Random distribution of sampling points is ideal but unachievable in Whangamarino. Systematic sampling from accessible transects that are representative of typical of fernbird have been chosen (Figure 1‐ Mathew has draft). These are not set in stone until the field survey verifies that each station is suitable and there should be some flexibility about precise location of stations so they are in sensible listing positions and adjacent the most suitable habitat within 50 m of the station (e.g., if there is a pond with surrounding sedges close to the station, use that position). Record all locations with GPS and map.

PAGE 10 OF 14 h. Time of year: Three sessions initially (November 2012, February and late September/early October 2013). Once these sessions have been analysed we will decide on the optimum time for future monitoring. i. Time of day: Counts need to avoid the middle of the day when birds are naturally quiet. Focus sampling on dusk and dawn: 0600 hrs‐1000 hrs and 1500 hrs‐1900 hrs. j. Survey conditions: In order to minimise some of the variability in counts, standardising environmental conditions as much as possible. Generally avoid strong winds (> 10 knots) and rain or other noisy conditions that limit hearing. k. Count protocol: Count all fernbird seen or heard during the count.

 Fill in the field sheet (below) completely, including current weather conditions.  Estimate distance to each different fernbird when it first calls in metres with a range finder if possible (We are trialling distance sampling, but fernbird often move towards the speaker so later observations of the same bird may be biased). Observers should indicate how well they think they can estimate distance.  Record other native species seen and heard just like in a normal 5‐minute bird count because monitoring may yield useful information for them as well. l. Field sheet: Use the draft datasheet (DOCDM‐xxxx), filling in all boxes, including drawing estimated locations of calls. The diagram helps the observer keep track of where birds are calling from. Record the direction you are facing with a compass bearing. m. Data input: Enter data into an Excel spreadsheet (for format see (DOCDM‐xxxx),

3. EXPLANATION Responses of swamp birds to predator control have not been measured in . Predator control at Whangamarino is intended to halt further declines in populations of threatened swamp birds (Australasian bittern, marsh crake, spotless crake, fernbird). However the extent to which numbers may then increase is uncertain.

Our approach to monitoring is that we will gather 2 types of data for analysis: calculation of an index of relative abundance and a trial using distance sampling. Distance data can be collected

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PAGE 11 OF 14 simultaneously with no additional effort and if the data are reliable we can correct indices taking into account detection probability, which provides a better population index.

Measures will be:  An index of calls/unit time  Estimate of the total number of different individuals recorded  Presence/not detected data per station  Estimated distance to bird.

4. EQUIPMENT  Map of stations  GPS  Compass  Playback speaker and MP3player with calls  Timer/stopwatch or watch  Standard field data sheets

Standardised call‐playback protocol for monitoring spotless crake at Whangamarino wetland

5. OBJECTIVE C. To estimate population trends in spotless crake using indices of relative abundance in areas with and without predator trapping at Whangamarino wetland. D. To establish a baseline index against which to monitor future trends.

6. COUNT PROTOCOLS a. Five‐year performance measure: No significant declines in indices of spotless crake abundance after 5‐yearsof continuous trapping. b. Count type: Call‐playback and listening at point stations. c. Count length: 5 minutes per count. d. Sample size: 100 counts per sampling session (50 in treatment area, 50 in non‐ treatment).

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e. Playback protocol: On arrival at the count station use a standard call playback MP3 (provided by DOC/Emma Williams) to elicit calls on the counts. The playback contains a series of call sequences as well as pre‐recorded periods of silence. It plays:

 Play=30sec + Listen=30s + P=15s + L=30s + P=15s + L=30s + P=15s + L=30 + P=15s + L=2 minutes (End) f. Distance between stations: 200 m. g. Frequency: Annual. h. Location of stations: Random distribution of sampling points is ideal but unachievable in Whangamarino. Systematic sampling from accessible transects that are representative of typical of spotless crake have been chosen (Figure 1‐Mathew has draft). One of the non‐treatment lines will be at Black Lake. These are not set in stone until the field survey verifies that each station is suitable and there should be some flexibility about precise location of stations so they are in sensible listing positions and adjacent the most suitable habitat within 50 m of the station (e.g., if there is a pond with surrounding sedges close to the station, use that position). Record all locations with GPS and map. i. Time of year: Three sessions initially (November 2012, February and late September/early October 2013). Once these sessions have been analysed we will decide on the optimum time for future monitoring. j. Time of day: Spotless crake appear to respond to calls throughout the day. However, counts need to avoid the middle of the day when birds are naturally quiet. Focus sampling on dusk and dawn: 0600 hrs‐1000 hrs and 1500 hrs‐1900 hrs. k. Survey conditions: In order to minimise some of the variability in counts, standardising environmental conditions as much as possible. Generally avoid strong winds (> 10 knots) and rain or other noisy conditions that limit hearing. l. Count protocol: Count all spotless crake heard during the count.

 Set up the speaker facing the wetland and commence playback once organised.

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 The observer should stand 2 metres from the speaker.  Record total number of calls and the time they were elicited.  Fill in the field sheet (below) completely, including current weather conditions.  Estimate distance to each different bird when it first calls in metres with a range finder if possible (We are trialling distance sampling, but crake often move towards the speaker so later observations of the same bird may be biased). Observers should indicate how well they think they can estimate distance.  NOTE: Listen for other swamp birds at the same time (e.g., bittern, fernbird) and record their numbers. m. Field sheet: Use the draft datasheet (DOCDM‐xxxx), filling in all boxes, including drawing estimated locations of calls. The diagram helps the observer keep track of where birds are calling from. Record the direction you are facing with a compass bearing. n. Data input: Enter data into an Excel spreadsheet (for format see (DOCDM‐xxxx),

7. EXPLANATION Responses of swamp birds to predator control have not been measured in New Zealand. Predator control at Whangamarino is intended to halt further declines in populations of threatened swamp birds (Australasian bittern, marsh crake, spotless crake, fernbird). However the extent to which numbers may then increase is uncertain.

Our approach to monitoring is that we will gather 2 types of data for analysis: calculation of an index of relative abundance and a trial using distance sampling. Distance data can be collected simultaneously with no additional effort and if the data are reliable we can correct indices taking into account detection probability, which provides a better population index.

Measures will be:  An index of calls/unit time  Estimate of the total number of different individuals recorded  Presence/not detected data per station  Estimated distance to bird.

8. EQUIPMENT  Map of stations  GPS

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 Compass  Playback speaker and MP3player with calls  Timer/stopwatch or watch  Standard field data sheets

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