October 2016
This report describes the results of continued population monitoring of black petrels at Great Barrier Island, Little Barrier Island and Moehau Range, Coromandel in 2015/16.

These are the final reports for the black petrel population study on Great Barrier Island, Little Barrier Island and Moehau Range 2015/16. This ongoing population study now sits with MPI, the 2016/17 report can be found here, the 2017/18 report is currently being drafted.


Part 1) Great Barrier Island
During the 2015/16 breeding season, 433 numbered burrows within the 35-ha study area near Mount Hobson/Hirakimata were checked and intensively monitored. Of these 419 are used as study burrows and 286 were used by breeding pairs, 75 by non-breeding adults and the remaining 59 burrows were non-occupied.

By 10 May 2016, 191 chicks were still present in the study burrows, corresponding to a breeding success of 66.8%. Nine census grids were monitored within the study area and accounted for 164 of the inspected burrows and 154 of the study burrows, with 103 burrows being used for breeding.

There were 108 chicks from earlier breeding seasons recaptured within the Mount Hobson/Hirakimata colony area this season (a total of 254 'returned chicks' have been caught since the 1999/2000 season).

Over 1550 hours of recordings were collected by automated acoustic recording units showing black petrels began calling between 2100 and 2252 hours and that activity was highest near the summit (Mt Hobson/Hirakimata). Mean clacking rate varied between 1.1 to 12.7 clacks per minute.

Analysis of the stratified census grid and mean transect data estimated that there were 1947 to 2197 birds present in the 35-ha area around Mount Hobson/Hirakimata Unfortunately the tracking and diving behaviour work could not be completed due to technical failure of both the GPS and TDR devices. 

Part 2) Little Barrier Island
On Hauturu-o-Toi/Little Barrier Island, 149 study burrows were monitored, of which 92 were original study burrows established in 1997 by Mike Imber.Only 56% were being used by breeding pairs, but those pairs had 85.2% breeding success with 69 chicks fledging this season.

Twenty automated acoustic devices were placed out across Hauturu-o-Toi/Little Barrier Island in December 2015 and were retrieved in March 2016. Black petrel calls were recorded at five locations: Thumb Ladder (LC7), Summit (LC11), Track 7 junction (LC15), Track 8 highpoint (LC16) and Track 8 halfway to Mt Kiriraukawa (LC17.

Thirty-six transects were completed with a total of 49 breeding, 18 non-breeding and 50 unoccupied burrows found (n = 117 burrows).

Surveys with a seabird-detector dog covered 52.5 km (approximately 73 ha) finding 121 breeding burrows. Analysis of the acoustic recorder units and surveys estimated that there were approximately 620 breeding pairs of black petrels present on Hauturu-o-Toi/Little Barrier Island.

Part 3) Moehau range
An important factor for addressing the estimation of the total black petrel (Procellaria parkinsoni) population is to identify any additional breeding sites away from Great Barrier Island/Aotea and Hauturu-o-Toi/Little Barrier Island.

The Moehau Range, Coromandel was identified as one possible area for black petrel as shown by historical presence. Nocturnal seabirds are ideal candidates for acoustic monitoring because they are highly vocal at their colonies, particularly during the breeding season.

Black petrels call on the ground when trying to attract mates to their burrows between October and February, with peak activity between November and January. Seventeen automated acoustic recording units were deployed on the Moehau range between 30 November 2015 and 31 January 2016. No black petrel calls were recorded, but Cook's petrel (Pterodroma cookii) flight calls were recorded. 

Publication information

Bell, E.A.; Mischler, C.P.; MacArthur, N.; Sim, J.L.; Scofield, R.P. 2016. Population parameters of black petrels (Procellaria parkinsoni) on Great Barrier Island/Aotea, 2015/16. Report by Wildlife Management International Ltd for the New Zealand Department of Conservation. Wellington. 58p.

Bell, E.A.; Mischler, C.P.; MacArthur, N.; Sim, J.L. 2016. Black petrel (Black petrel (Procellaria parkinsoni) population study on Hauturu-o-Toi/Little Barrier Island, 2015/16. Report prepared by Wildlife Management International Ltd for the New Zealand Department of Conservation, Wellington. 24p 

Bell, E.A.; Stewart, P. 2016. Black petrels (Procellaria parkinsoni) population study on Moehau Range, Coromandel, 2015/16. Report prepared by Wildlife Management International Ltd for the New Zealand Department of Conservation, Wellington. 10p.


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