MEMO To: Andy Hicks From: Keiko Hashiba Date: 5 November 2018 RESULTS OF CRYPTIC BIRD 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 species 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 birds 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. PAGE 2 OF 14 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. M:\E_Science\Projects\340 Land Monitoring\340-206 Wetland Monitoring\20181023 Whakaki cryptic bird survey\Memo_Whakaki cryptic bird survey results October 2018_revised.docx PAGE 3 OF 14 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 M:\E_Science\Projects\340 Land Monitoring\340-206 Wetland Monitoring\20181023 Whakaki cryptic bird survey\Memo_Whakaki cryptic bird survey results October 2018_revised.docx 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 (Typha orientalis). 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. M:\E_Science\Projects\340 Land Monitoring\340-206 Wetland Monitoring\20181023 Whakaki cryptic bird survey\Memo_Whakaki cryptic bird survey results October 2018_revised.docx Figure 1. Location of bird count stations. PAGE 6 OF 14 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. M:\E_Science\Projects\340 Land Monitoring\340-206 Wetland Monitoring\20181023 Whakaki cryptic bird survey\Memo_Whakaki cryptic bird survey results October 2018_revised.docx PAGE 7 OF 14 Figure 3. Result of fernbird count. Birds were either heard or observed. M:\E_Science\Projects\340 Land Monitoring\340-206 Wetland Monitoring\20181023 Whakaki cryptic bird survey\Memo_Whakaki cryptic bird survey results October 2018_revised.docx PAGE 8 OF 14 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.