Hidden in the wetlands : evaluating playback effectiveness and wetland preferences of the Spotless Crake : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Zoology at Massey University, Manawatū, New Zealand

Abstract

The current knowledge about the cryptic wetland bird Spotless Crake (Zapornia tabuensis) is very limited, particularly in relation to its habitat preferences and optimal survey methods. This study aimed to address these gaps by conducted targeted acoustic surveys alongside detailed vegetation mapping and analysis across a range of wetlands in the Manawatū-Whanganui region, New Zealand. Call playback surveys were conducted to investigate factors influencing detection probability and calling rates using generalised linear mixed models to evaluate the effects of environmental and survey variables. Vegetation composition and structure were analysed to investigate associations between habitat characteristics and crake presence. Findings indicate that spotless crake are more likely to occur in wetlands supporting dense fringing vegetation that is dominated by tall emergent species, and also that some habitat flexibility was observed. Detection probability was influenced by both temporal and environmental factors, which underscores the requirement for standardised survey protocols. This study provided invaluable insight into the ecology and monitoring of Spotless Crake, and broader implications for the conservation of other cryptic, wetland-dependent species.