Scientific publications from the NZ Penguin Initiative

Erect-crested penguins on the Bounty Islands: population size and trends determined from ground counts and drone surveys

Thomas Mattern, Kalinka Rexer-Huber, Graham C Parker, Jacinda Amey, Paige Green, Alan J D Tennyson, Paul Sagar, David R Thompson
Published March 2021

In October 2019, an expedition to the subantarctic Bounty Islands provided the opportunity to conduct comprehensive ground counts of erect-crested penguins to assess population size and compare numbers to previous surveys. The entirety of Proclamation Island, an erect-crested penguins’ stronghold, was surveyed and number of active penguin nests was determined via ground counts. Drone surveys aiming at assessing seal numbers, provided high-resolution aerial photography allowing spatial analysis of penguin nest densities on four islands, i.e. Proclamation, Tunnel, Spider, and Ranfurly Islands. A total of 2,867 penguin nests were counted on Proclamation Island between 24 and 29 October. Adjusting for the earlier timing of the survey compared to counts conducted since 1997, nest numbers were only marginally lower (~2.4%) than in 1997 and 2004 suggesting that the penguin population has remained stable for the past 20 years; a ~10% reduction in penguin numbers in 2011 seems to be related to warmer than average ocean temperatures that year. Density analysis from drone imagery showed highly heterogenous distribution of penguin nests, with birds preferring areas sheltered from prevailing south-westerly winds. This also means that a previous estimate from 1978 which relied on uniform extrapolation of nest densities to what was assumed to suitable breeding areas substantially overestimated the true population size, thereby contributing to the species current ‘endangered’ threat ranking.

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New Zealand penguins Current knowledge and research priorities

Thomas Mattern & Kerry-Jayne Wilson
Published April 2019

“In this report, we collate the information available on all six New Zealand penguin species. This includes published accounts (scientific papers, reports), grey literature (unpublished reports and data sets), and personal observations made by researchers that have worked with New Zealand penguins.

Based on our findings, we compile a list of research priorities that should aid closing many of the knowledge gaps that prevent effective evidence-based conservation management.”