Factors Affecting the Nest Survival of Painted Stork (Mycteria leucocephala) at Khao Kheow Open Zoo in Eastern Thailand

Abstract

Background and objectives: The painted stork is a large wading bird that once considered as rare but now distributed across many regions in Thailand. However, suitable nesting sites remain limited, while, Khao Kheow Open Zoo is the most significant location where painted storks frequently establish nests. This study aimed to analyze the monthly age classes of painted stork chicks and to identify the factors influencing nest survival at Khao Kheow Open Zoo during 2020 and 2021.

Methodology: The nesting site survey involved recording various details, including nest coordinates, number     of nests, start date of nest construction, egg incubation date, number of chicks, date of parent abandonment, chick age, fledging date, and factors affecting chick survival. The analysis utilized the following methods; Mayfield to estimate the nest survival rate, Kaplan-Meier to estimate survival probability over time, Generalized Linear Model (GLM) to analyze factors affecting nest survival, such as temperature, wind speed, relative humidity, rainfall, nest age, and nest height.

Main results: The painted stork began nesting in early August and varied periods among individuals, resulting age differed between the chicks. The highest nesting activity was observed in January. The study found that the daily survival rate of the nests was 0.997, and the overall nest survival rate was 74%. Survival rates declined during the nesting and incubation periods but stabilized after the eighth weeks, coinciding with chicks older than 16 days. The age of the chicks is the most critical factor affecting survival, with older chicks exhibiting higher survival rates.

Conclusion: The survival rate of nests during the early nesting and incubation periods was found to be low. Successful nests were often associated with chicks older than 16 days.