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BCBC2020-05a: King shag population census by Toroa Consulting (PDF, 575K)

Summary

During the 2021 kawau pāteketeke/New Zealand king shag breeding season breeding at two colonies was asynchronous. In order to estimate the breeding population, we combined data from aerial surveys, boat based observations and a drone survey to estimate the total breeding population for kawau pāteketeke/ New Zealand king shag in 2021 of 253 pairs.

Aerial surveys continue be a cost-effective tool for monitoring the numbers of kawau pāteketeke/New Zealand king shag. Although surveys must account for variation in the time of breeding between colonies. The quality of aerial images significantly affected the results and is was one source of variation among assessors.

Further refinements to the methodology, execution and supply of aerial images are warranted, including the possibility of using drones to acquire the necessary imagery. Variation in counts among assessors could perhaps be reduced by refining and standardising the criteria on which birds in the colonies are classified when aerial images are analysed.

Publication information

Bell, M.; Frost, P; Schuckard, R. 2022. Breeding population assessment of kawau pāteketeke/New Zealand king shag in the Marlborough Sounds: 2021 breeding season. Unpublished client report for Marine Species Team, Biodiversity Group, Department of Conservation, Wellington.