Aeʻo (Hawaiian Stilt, Himantopus mexicanus knudensi) Reproduction and Survival

Abstract

With global biodiversity declining, research in reproductive biology is necessary to understand population dynamics and develop strategies for the conservation of threatened and endangered species. Following listing as ‘endangered’ under the Endangered Species Act (ESA) in 1970, the Aeʻo (Hawaiian Stilt, Himantopus mexicanus knudensi) population has steadily increased due to the designation and protection of wetland areas across the main island chain, and conservation actions such as predator control, habitat restoration, and educating the public. However, the species continues to be conservation-reliant, with continued human intervention necessary to maintain populations. This study filled gaps in knowledge regarding survival and reproduction dynamics for Aeʻo. In Chapter 1, I: (1) compiled and evaluated data pertaining to Aeʻo reproduction and survival since they were ESA-listed in 1970; and (2) determined and assessed reproductive trends over time. In Chapter 2, I: (1) calculated chick survival rates; and (2) explored chick home range sizes in relation to patch size and survival. Key results of this thesis were that: (1) overall Aeʻo reproductive success has not changed over the last 50 years, though there have been increases in nesting and fledging success; (2) chick movement is restricted by barriers such as roads, fences, and developed areas; and (3) chick mortality is high, with 86% of chicks perishing in the first seven days of life. This information, amongst other results and outputs within this thesis, may be useful in decision-making, future analyses, and implementing management actions. Also included in this thesis are recommended management actions based on the results of this study.